WO2016002917A1

WO2016002917A1 - Vibration-type actuator, lens barrel, image-capturing device, and automatic stage

Info

Publication number: WO2016002917A1
Application number: PCT/JP2015/069218
Authority: WO
Inventors: 関　裕之
Original assignee: キヤノン株式会社
Priority date: 2014-06-30
Filing date: 2015-06-26
Publication date: 2016-01-07
Also published as: JP2016027780A

Abstract

A vibration-type actuator 100 is provided with: vibrating elements 3 configured by having a piezoelectric element 2 and a vibrating plate 1 joined together; support members 6 for supporting the vibrating element 3; a rotor 4 that is a driven body contacting the vibrating elements 3 and moving correspondingly therewith; and a pressurizing mechanism having a pressurizing member 5 that comes in contact with the vibrating elements 3, said mechanism pressing the pressurizing member 5 against the vibrating elements 3, and thereby applying pressure to the vibrating elements 3 against the rotor 4. Two support arm parts 6c joined with the vibrating elements 3 are provided to the support member 6 so that there is high rigidity in the direction in which the rotor 4 moves, but little rigidity in the direction in which the pressurizing force acts. A structure is adopted in which the pressurizing member 5 coming into contact with a prescribed region of the piezoelectric element 2 causes the orientation of the vibrating elements 3 to align with the pressurizing member 5, whereby the orientation of the vibrating elements 3 with respect to the rotor 4 is kept stable and the accuracy with which the vibrating elements 3 is positioned is kept high.

Description

Vibration actuator, lens barrel, imaging device, and automatic stage

The present invention relates to a vibration type actuator, a lens barrel having a vibration type actuator, an imaging device, and an automatic stage.

A predetermined vibration mode is excited in a vibrator formed by joining an electro-mechanical energy conversion element such as a piezoelectric element to an elastic body such as a metal to cause an elliptical motion on the surface of the elastic body and contact the elastic body. A vibration type actuator for driving a driven body is known. The vibration type actuator is also called an ultrasonic motor or a vibration wave motor, and various structures have been proposed. For example, as an actuator for rotationally driving a lens barrel such as a camera, a ring-shaped ultrasonic motor, a rod-shaped rotary ultrasonic motor, or a rotary ultrasonic motor having a plurality of chip-shaped vibrators arranged on the circumference Various types of structures have been proposed.

Vibrating actuators such as ultrasonic motors that use vibrators have features that output torque per unit volume is larger than electromagnetic motors, and can be reduced gearless (direct drive), thus reducing size It is suitable for driving sources such as lens barrels that are becoming lighter. In particular, the vibration-type actuators that combine chip-shaped vibrators have the advantage of being able to achieve both space saving and low cost, as well as high design flexibility with respect to the dimensions and shape of the applied lens barrel, etc. There are benefits.

For example,

Patent Documents

1 and 2 disclose vibration type actuators that combine chip-shaped vibrators. In Patent Document 1, there are two contact portions on one surface, each contact portion generates an elliptical vibration, and contacts (pressurizing contact) with the contact portion of the vibrator. An ultrasonic motor having a rotor (driven body) driven by elliptical vibration is described. In this ultrasonic motor, a support shaft is provided at a portion that becomes a node of vibration when vibration is excited in the vibrator, and the vibrator is pressed against the rotor by a pressure spring through the support shaft. The part is brought into contact with the rotor, so that the rotor can be friction driven by the contact part. In addition, a guide groove extending in the pressurizing direction is provided in the housing so that the pressurizing spring bends and the vibrator can move in the pressurizing direction when the rotor is friction driven, and the support provided on the vibrator is provided. The shaft is fitted in the guide groove. In addition, by supporting the vibrator so as to be rotatable around the support shaft so that the contact surface of the rotor and the contact portion of the vibrator can stably contact, the vibrator follows the contact surface of the rotor. It has a structure that can be tilted.

Patent Document 2 includes a rectangular vibrator having at least one vibration node, a support member that is fixed in the vicinity of the joint of the vibrator and supports the vibrator, and a rotor that is rotatably disposed. An ultrasonic motor is described. In this ultrasonic motor, a support member is formed by bending a part of a ring-shaped base in a direction in which pressure is applied to the rotor to form a cantilever, and the vibrator is disposed at the end of the support member. Yes. In this way, a function as a pressure spring that urges the applied pressure between the rotor and the vibrator is imparted to the support member.

In the ultrasonic motors described in

Patent Documents

1 and 2, by adopting the above-described vibrator support structure, when the flatness of the contact surface of the rotor with the vibrator is low or the support member and the rotor are parallel to each other. Even when the degree is low, an appropriate contact state between each vibrator and the rotor can be maintained.

JP 2006-158053 A Japanese Patent Application Laid-Open No. 11-235062

In the support structure of the vibrator described in

Patent Documents

1 and 2, the support rigidity of the vibrator is set small so that the vibrator can easily follow the contact surface of the rotor. Therefore, when the driving of the ultrasonic motor is stopped, the vibrator and the rotor can be stably maintained in a good contact state.

However, when the ultrasonic motor is driven, the vibrator is driven in the driving direction (the contact portion of the vibrator and the rotor) by the frictional driving force exerted on the contact surface of the rotor and the support reaction force generated in the support section of the vibrator. A moment that tilts in the direction in which the relative position of the contact portion changes) is generated. Therefore, when the support rigidity of the vibrator is small, the vibrator easily tilts with respect to the frictional sliding surface of the rotor due to a moment that tilts the vibrator in the driving direction. As a result, an operation sound (abnormal sound) called output reduction or squealing occurs.

The ultrasonic motor described in Patent Document 1 has a structure in which a support shaft fixed to a vibrator and the vibrator are integrated into a guide groove provided in the housing. In this structure, there is a backlash corresponding to the dimensional tolerance between the support shaft and the guide groove, which reduces the positioning accuracy of the vibrator, and thus reduces the controllability of the ultrasonic motor.

An object of the present invention is to provide a vibration type actuator that can stably hold the posture of a vibrator with respect to a driven body and can maintain high positioning accuracy of the vibrator.

The vibration-type actuator according to the present invention includes an electro-mechanical energy conversion element, a vibrator having an elastic body to which the electro-mechanical energy conversion element is bonded, and a target that comes into contact with a drive unit provided in the vibrator. A driving body and a pressing member that supports the vibrator, and a pressing means that presses the vibrator against the driven body by pressing the pressing member against the vibrator; The vibrator and the driven body are configured such that a relative position between the vibrator and the driven body is changed by vibration excited by the vibrator, and the relative position is changed. In a plane including a pressing direction in which the pressing unit presses the vibrator against the driven body, the posture of the vibrator is configured to follow the pressing member rather than the driven body. It is characterized by.

Another vibration type actuator according to the present invention is applied to an electro-mechanical energy conversion element, a vibrator having an elastic body to which the electro-mechanical energy conversion element is joined, and a drive unit provided in the vibrator. A pressurizing unit having a driven body to be in contact with and a pressurizing member for supporting the vibrator; and pressing the vibrator against the driven body by pressing the pressurizing member against the vibrator The vibrator and the driven body are configured such that a relative position between the vibrator and the driven body is changed by vibration excited by the vibrator, and the pressure member is One or a plurality of parts that contact the vibrator, the vibrator includes one or a plurality of parts that contact the driven body, and the pressurizing unit drives the vibrator When viewed from the direction of pressure applied to the body, Of the region where the pressure member is in contact with the vibrator or the region formed by connecting the plurality of portions where the pressure member is in contact with the vibrator (in one case, the region), the region having the largest area is the first. Area of the region where the vibrator contacts the driven body or a region formed by connecting a plurality of portions where the vibrator contacts the driven body (in the case of one area) When the region having the largest value is the second region, the first region is larger than the second region, and the first region and the second region include the vibrator and the driven body. In order not to rotate, at least a part overlaps when viewed from the pressurizing direction.

Still another vibration actuator according to the present invention includes an electro-mechanical energy conversion element, a vibrator having an elastic body to which the electro-mechanical energy conversion element is joined, and a drive unit provided in the vibrator. A pressure member that has a driven body that abuts and a pressure member that supports the vibrator, and presses the vibrator against the driven body by pressing the pressure member against the vibrator; And the vibrator and the driven body are configured such that a relative position between the vibrator and the driven body is changed by vibration excited by the vibrator, and the vibrator is A surface of a portion where the vibrator receives a force from the pressurizing means when supported by the pressurizing means without coming into contact with the driven body is a first surface, and the vibrator is the pressurizing means. When supported by the driven body without contacting with The surface of the portion where the vibrator receives a force from the driven body is the second surface, and when a force perpendicular to the first surface is applied to the second surface, it acts on the first surface. The sum of absolute values of rotational moments about the centroid of the second surface due to the reaction force is defined as the first moment, and the force and magnitude perpendicular to the first surface are equal to and perpendicular to the second surface. The sum of absolute values of rotational moments about the centroid of the first surface due to the reaction force acting on the second surface when a large force is applied to the first surface is defined as the second moment. Sometimes, the vibrator, the driven body, and the pressurizing means are in a plane including a direction in which the relative position changes and a pressurizing direction in which the pressurizing means presses the vibrator against the driven body. The first moment is configured to be larger than the second moment. To.

According to the present invention, the vibrator can be accurately positioned with respect to the frictional sliding surface of the rotor and can be firmly held while keeping the support rigidity of the vibrator large. As a result, the vibrator can be stably held even when an external force or an impact force at the time of reversal is applied when the vibration actuator is driven, and a stable drive characteristic (output characteristic) can be obtained.

It is a top view which shows schematic structure of the vibration type actuator which concerns on 1st Embodiment of this invention. It is a front view which shows schematic structure of the drive unit which comprises the vibration type actuator of FIG. 1A. It is sectional drawing corresponding to FIG. 1B. It is a top view (plan view) showing a structure of a vibrator constituting the drive unit of FIGS. 1B and 1C. It is a side view corresponding to FIG. 2A. It is a front view corresponding to FIG. 2A. It is a 1st schematic diagram explaining the rotational moment of the vibrator | oscillator in the vibration type actuator of FIG. 1A. It is a 2nd schematic diagram explaining the rotational moment of the vibrator | oscillator in the vibration type actuator of FIG. 1A. It is a perspective view which shows the structure of the supporting member which comprises the drive unit of FIG. 1B and 1C. It is a front view which shows the state which attached the vibrator | oscillator to the supporting member of FIG. 4A. 1B is a top view (plan view) schematically showing a state in which a conventional method is applied as a pressurizing method for pressing a vibrator against a rotor in the vibration type actuator of FIG. 1A. FIG. It is a side view corresponding to the top view of FIG. 5A. It is a front view corresponding to the top view of FIG. 5A. FIG. 6 is a diagram schematically showing a state in which a good contact state between the convex portion of the vibrator and the rotor cannot be obtained in the pressurization method of FIG. 5. FIG. 6B is a first side view corresponding to the top view of FIG. 6A. FIG. 6B is a second side view corresponding to the top view of FIG. 6A. It is a front view which shows schematic structure of the drive unit which comprises the vibration type actuator which concerns on 2nd Embodiment of this invention. FIG. 7B is a top view (plan view) schematically showing the contact state of the pressure member with the vibrator in the drive unit of FIG. 7A. FIG. 7B is a diagram for explaining the relationship between the contact region where the pressure member contacts the vibrator and the structure of the vibrator in the drive unit of FIG. 7A. FIG. 7B is a side view showing a state where the pressing member presses the vibrator against the rotor in an ideal state in the drive unit of FIG. 7A. FIG. 7B is a side view schematically showing the contact state between the vibrator and the rotor when it is assumed that the pressure member and the rotor are not installed in parallel in the drive unit of FIG. 7A. It is a front view which shows the state which joined the vibrator | oscillator to the supporting member which comprises the vibration type actuator which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the structure of the supporting member shown to FIG. 9A. It is a front view which shows schematic structure of the drive unit which comprises the vibration type actuator which concerns on 4th Embodiment of this invention. It is sectional drawing of the drive unit of FIG. 10A. It is a front view which shows the partial structure of the pressurization member which comprises the vibration type actuator which concerns on 5th Embodiment of this invention. It is a top view which shows schematic structure of the vibrator | oscillator which comprises the vibration type actuator which concerns on 5th Embodiment of this invention. It is a side view corresponding to the top view of FIG. 11B. It is a front view corresponding to the top view of FIG. 11B. It is a top view which shows schematic structure of the vibration type actuator which concerns on 6th Embodiment of this invention. It is a front view corresponding to FIG. 12A It is a top view which shows schematic structure of the vibration type actuator which concerns on 7th Embodiment of this invention. It is a front view corresponding to FIG. 13A. It is a fragmentary sectional view corresponding to FIG. 13A. It is a top view which shows schematic structure of an imaging device provided with the vibration type actuator which concerns on embodiment of this invention. It is an appearance perspective view of a microscope which has an XY stage provided with a vibration type actuator concerning an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, “the posture of the member A follows the member C from the member B” means “when the surface of the member B and the member C facing the member A is non-parallel, the member A is more than the member B. “To be in a posture along the inclination of C” or “When member B and member C move by the same amount, member A takes a posture that is more strongly influenced by member C than member B”.

A first embodiment of the present invention will be described. FIG. 1A is a plan view (top view) showing the overall structure of the vibration type actuator 100 according to the first embodiment of the present invention. FIG. 1B is a front view showing a schematic structure of the drive unit 200 constituting the vibration type actuator 100, and FIG. 1C is a cross-sectional view showing a schematic structure of the drive unit 200. The front view of FIG. 1B shows a schematic structure of the drive unit 200 when the inner diameter side is viewed from the outer diameter side of the vibration type actuator 100 shown in FIG. 1A, and the cross-sectional view of FIG. 1C is shown in FIG. It is sectional drawing in arrow LL.

The vibration type actuator 100 includes a cylindrical fixing member 8, a rotor 4 that is an annular driven body, and a plurality of balls 7 disposed between the fixing member 8 and the rotor 4. The fixing member 8 includes a cylindrical main body 8a, and a flange portion 8b that is formed integrally with the main body 8a so as to protrude to the outer diameter side of the main body 8a. A V-groove is formed in a surface of the flange portion 8b facing the rotor 4 so as to be concentric with the main body 8a, and a surface of the rotor 4 facing the flange portion 8b is also formed in the V-shaped portion 8b. A V-groove is formed at a position facing the groove (see FIG. 1C). The plurality of balls 7 are sandwiched between the flange portion 8 b and the V groove of the rotor 4 at substantially equal intervals in the circumferential direction of the V groove. As a result, a bearing (ball bearing) in which the rotor 4 is rotatable (movable) relative to the fixed member 8 is configured.

The drive unit 200 of the vibration type actuator 100 includes a support member 6 that is fixed to the fixing member 8 with screws 11, a vibrator 3 that is joined to the support member 6, and a pressure that presses the vibrator 3 against the rotor 4. Mechanism. The vibrator 3 includes a diaphragm 1 that is an elastic body that contacts a surface of the rotor 4 on which no V-groove is formed, and a piezoelectric element 2 that is an electro-mechanical energy conversion element that excites predetermined vibration on the diaphragm 1. Have A flexible printed circuit board (not shown) that applies a predetermined alternating voltage (drive voltage) is attached to the piezoelectric element 2. The support member 6 is fixed to the outer peripheral wall of the main body 8a of the fixing member 8 with a screw 11 in a state where the vibrator 3 is bonded. The pressure mechanism includes a pressure spring 9, a spring holding member 10 that is fixed to the main body 8a of the fixing member 8 and holds the pressure spring 9, and between the pressure spring 9 and the piezoelectric element 2 (vibrator 3). And a pressurizing member 5 disposed on the surface. The pressure member 5 presses the vibrator 3 against the rotor 4 by the biasing force of the pressure spring 9.

2A, 2B and 2C are a top view (plan view), a side view and a front view showing the structure of the vibrator 3, respectively. The diaphragm 1 constituting the vibrator 3 includes, for example, a rectangular diaphragm main body 1a and a diaphragm arm 1b extending from the end of the diaphragm main body 1a in the longitudinal direction of the diaphragm main body 1a. Have The diaphragm 1 is formed, for example, by punching a metal thin plate or the like. As will be described later, the two diaphragm arm portions 1b of the diaphragm 1 are joined to the two support arm portions 6c provided on the support member 6 by spot welding or the like.

A piezoelectric element 2 is bonded to one surface (upper surface) of the diaphragm main body 1a by adhesion or the like, and bosses 1c are provided at two locations on the other surface (lower surface) of the diaphragm main body 1a. Yes. At the center of the tip of each of the two boss portions 1 c, a convex portion 1 d that is a contact portion with the rotor 4 and serves as a drive portion that drives the rotor 4 is provided. The two convex portions 1d are in contact with the surface (friction sliding surface) on which the V-groove of the rotor 4 is not formed by the urging force of the pressurizing mechanism (see FIG. 1B).

A flexible printed board (not shown) is bonded to the piezoelectric element 2 by adhesion or the like. When an alternating voltage is applied from the power source to the piezoelectric element 2 through the flexible printed circuit board, two different standing wave vibrations are excited by the vibrator 3, thereby exciting an elliptical vibration at the convex portion 1 d of the diaphragm 1. . Thereby, the rotor 4 in contact with the convex portion 1d is frictionally driven by the elliptical vibration of the convex portion 1d, and the relative position between the contact portion of the vibrator 3 and the contact portion of the rotor 4 is changed (hereinafter referred to as “drive direction”). "). In the first embodiment, this driving direction is a direction connecting the two convex portions 1d to the vibrator 3, and the fixing member 8 is fixed to an external member (not shown) and does not move. Therefore, in the following description, it is assumed that the rotor 4 is rotationally driven with respect to the vibrator 3 whose position with respect to the fixing member 8 does not change.

Here, the rotational moment of the vibrator 3 will be described. 3A and 3B are a first schematic diagram and a second schematic diagram, respectively, for explaining the rotational moment of the vibrator 3. Consider a state in which the vibrator 3 is supported by the pressurizing mechanism without contacting the rotor 4. That is, in FIGS. 1B and 1C, when the part from the vibrator 3 (the diaphragm 1) to the pressure spring 9 is taken out except for the support member 6 and the fixing member 8 and turned upside down, the vibrator 3 is connected to the rotor 4. A state in which the pressure mechanism is supported without contact is obtained. The surface of the portion of the vibrator 3 that is supported by the pressure mechanism at this time is defined as a first surface. Further, among the regions formed by connecting a plurality of portions where the pressurizing mechanism and the vibrator 3 abut on the first surface, the region having the largest area on the surface perpendicular to the pressurizing direction is shown in FIG. 3A. As shown, the first region S1.

Further, let us consider a state in which the vibrator 3 is supported by the rotor 4 without contacting the pressurizing mechanism. That is, in FIG. 1B and FIG. 1C, by removing the member above the pressure member 5 and the support member 6, a state where the vibrator 3 is supported by the rotor 4 without contacting the pressure mechanism is obtained. A surface of a portion of the vibrator 3 supported by the rotor 4 at this time is a second surface. Further, among the regions formed by connecting a plurality of portions where the vibrator 3 and the rotor 4 abut on the second surface, a region having the largest area on the surface perpendicular to the pressing direction is shown in FIG. 3B. In this way, the second region S2.

In the vibration type actuator 100, as shown in FIG. 3A, when a force Fa perpendicular to the first region S1 on the first surface is applied to the second region S2 on the second surface, A reaction force fa acts on the region S1. A sum of absolute values of rotational moments centered on the centroid G2 of the second region S2 due to the reaction force fa is defined as a first moment. Further, as shown in FIG. 3B, the force Fb that is equal in magnitude to the force Fa perpendicular to the first region S1 on the first surface and perpendicular to the second region S2 on the second surface is applied to the first region S1. When acting on the first region S1, the reaction force fb acts on the second region S2. A sum of absolute values of rotational moments about the centroid G1 of the first region S1 due to the reaction force fb is defined as a second moment. Here, the area of the first region S1 is larger than the area of the second region S2, and the first region S1 and the second region S2 are pressed in the pressing direction so that the vibrator 3 and the rotor 4 do not rotate. When seen from, at least partly overlaps.

Here, for convenience, the first region S1 is considered to be substantially the same as the outer shape of the upper surface of the piezoelectric element 2. In addition, the second region S2 has the outermost shape (outer shape) including the tip surfaces of the two convex portions 1d where the region formed by connecting the tip surfaces of the two convex portions 1d that are separated from each other is the largest. The centroid is defined as centroid G2.

In the first embodiment, the vibrator 3, the rotor 4, and the pressurizing mechanism are configured such that the first moment is larger than the second moment in a plane perpendicular to the driving direction. This is due to the following reason. That is, when the vibration actuator 100 is driven, the vibrator 3 and the rotor 4 (driven body) come into contact with each other to transmit the driving force, so that a force in the driving direction is applied to the contact portion of the vibrator 3 with respect to the rotor 4. . Then, a rotational moment about the direction orthogonal to the driving direction is likely to be generated in the vibrator 3. At this time, in the conventional vibrator, the first moment is smaller than the second moment, and the pressure mechanism side is configured to follow the contact portion with the driven body. Therefore, FIGS. 5A to 5C and FIGS. 6A to 6C are used. As will be described later with reference to, the contact state between the vibrator and the driven body may become unstable.

On the other hand, in the first embodiment, the first moment is made larger than the second moment to suppress the vibrator 3 from rotating by the pressurizing mechanism. That is, the posture of the vibrator 3 around the axis orthogonal to the drive direction follows the pressure mechanism side of the rotor 4 (driven body) in the plane including the drive direction and the pressure direction by the pressure mechanism. Thereby, it is possible to avoid the unstable contact state between the vibrator 3 and the rotor 4 and to drive the vibration actuator 100 stably.

For example, as a configuration, the first region S1 and the second region S2 are larger than the second region S2 when viewed from the pressurizing direction. Further, the first region S1 and the second region S2 overlap at least partially when viewed from the pressurizing direction so that the vibrator 3 and the rotor 4 do not rotate. Thereby, the posture of the vibrator 3 around the axis orthogonal to the drive direction follows the pressure mechanism side of the rotor 4 (driven body) in the plane including the drive direction and the pressure direction by the pressure mechanism. For example, the vibrator 3, the rotor 4, and the pressing member 5 are configured such that the center of the second region S2 is located inside the first region S1 when viewed from the pressing direction. Details will be described later in conjunction with the description of FIGS. 5A to 5C and FIGS. 6A to 6C.

In order to suppress the rotation of the vibrator 3 by the pressurizing mechanism, the first moment is the second moment even in the case of a rotational moment about the direction orthogonal to the pressurizing direction by the pressurizing mechanism and the direction orthogonal to the driving direction. It is desirable to make it larger. Similarly, the first region S1 is larger than the second region S2 when viewed from the pressing direction on the surface orthogonal to the pressing direction by the pressing mechanism, and the first region S1 and the second region S2 are In order to prevent the vibrator 3 and the rotor 4 from rotating, it is desirable that at least part of them overlap when viewed from the pressurizing direction. Thereby, rotation of the vibrator 3 can be suppressed by the pressurizing mechanism. For example, when the second region S2 is inside the first region S1 when viewed from the pressurizing direction, the rotation of the vibrator 3 can be suppressed by the pressurizing mechanism.

FIG. 4A is a perspective view showing the structure of the support member 6, and FIG. 4B is a front view showing a state where the vibrator 3 is attached to the support member 6. The support member 6 has a substantially L-shaped cross section, and can be manufactured by, for example, pressing a metal plate. The support member 6 has an attachment portion 6a for attachment to the fixing member 8, and a support portion 6b bent at about 90 ° from the attachment portion 6a. A screw hole 6d (attachment hole) for attaching the support member 6 to the fixing member 8 with screws 11 is provided in the attachment portion 6a.

At the end portion of the support portion 6b that is substantially parallel to the friction sliding surface of the rotor 4, two support arm portions 6c that are joined to the diaphragm arm portion 1b are provided. The two diaphragm arm portions 1b of the diaphragm 1 are joined to the two support arm portions 6c by spot welding or the like. Here, the support portion 6b has a low rigidity in the direction of arrow A, which is a pressing direction for pressing the convex portion 1d against the rotor 4, and is designed to be relatively easily deformable. Therefore, even if the support portion 6 b is deformed due to a variation in the thickness of the diaphragm 1 or a position error when the support member 6 is attached to the fixing member 8, the vibrator 3 is pressed against the rotor 4. The pressure does not change significantly. On the other hand, the support portion 6b has a large rigidity in the direction B connecting the two convex portions 1d and the rotation direction of the rotor 4, and is not easily deformed. Therefore, it is possible to avoid a decrease in positioning accuracy of the vibrator 3 due to a driving reaction force applied when the rotor 4 is driven and a reaction force (impact force) applied when the rotation direction of the rotor 4 is reversed.

Next, the posture maintaining function of the vibrator 3 in the drive unit 200 will be described. The tip surface (contact surface with the rotor 4) of the convex portion 1d provided on the boss portion 1c of the diaphragm 1 has an extremely small area. For example, in the first embodiment, it is designed to have a circular shape of about φ1 mm. This is derived from the driving principle of the vibrator 3 in which an elliptical vibration is generated in the convex portion 1d which is a part of the vibrator 3 by combining two different standing wave vibrations. That is, the standing wave vibration has a different amplitude and vibration direction depending on the position (location) in the vibrator 3, and therefore, when the standing wave of two different vibration modes is synthesized to generate an elliptical vibration, A region having the same direction is limited to a narrow range. Therefore, if the area of the front end surface of the convex portion 1d is increased and brought into contact with the rotor 4 at the same time, slippage occurs in the contact surface and drive efficiency is reduced. In order to avoid this problem, the convex portion 1d is configured to come into contact with the rotor 4 in a range where the transmission of the driving force can be appropriately performed and in the smallest possible area.

The front end surface of the convex portion 1d is a smooth surface that has been subjected to processing such as lapping in order to maintain a stable contact state with the friction sliding surface of the rotor 4, and the front ends of the two convex portions 1d. The surfaces are designed to be coplanar. Similarly, the frictional sliding surface with the convex portion 1d of the rotor 4 is also smooth and is subjected to surface processing such as lapping so that the warpage is extremely small.

In order to make the vibration type actuator 100 a highly efficient motor, it is ideal that the tip surfaces of the two convex portions 1d are in contact with the frictional sliding surface of the rotor 4 uniformly. Realizing the state is not easy. Therefore, conventionally, the two protrusions 1 d are brought into contact with the rotor 4 by pressing the vibrator 3 against the rotor 4.

5A, FIG. 5B and FIG. 5C are a top view (plan view), a side view and a front view, respectively, schematically showing a state where a conventional method is applied as a method of pressing the vibrator 3 against the rotor 4. 5A to 5C, the illustration of the rotor 4 is omitted. Conventionally, the vibrator 3 can be swung between the Rx direction and the Ry direction by applying point pressure to the central point P1 of the diaphragm 1 in the X direction (longitudinal direction) and the Y direction (short direction). As a result, the two convex portions 1d are configured to follow the frictional sliding surface of the rotor 4.

However, when the area of the tip surface of the convex portion 1d is small, a good contact state with respect to the rotor 4 of the convex portion 1d cannot be obtained when the position of the pressing point is shifted or the pressing direction is shifted. . FIG. 6A is a top view (plan view) schematically showing a state in which a good contact state of the protrusion 1d with the rotor 4 cannot be obtained. Since the state when viewed from the upper surface side is equivalent to the state of FIG. 5A, FIG. 6A is the same as FIG. 5A here. 6B and 6C are respectively a first side view and a second side view corresponding to FIG. 6A. As shown in FIG. 6B, if the concentrated load F2 is applied to a position shifted by ΔX1 from the center point P1 in the X direction, the vibrator 3 easily tilts in the Rx1 direction, and the convex portion 1d is good with respect to the rotor 4. A contact state cannot be obtained. As shown in FIG. 6C, the concentrated load F3 is applied to the center point P1. Similarly, when the direction is deviated from the X direction by the angle θ, the vibrator 3 is easily inclined in the Rxθ direction. Therefore, a good contact state of the convex portion 1d with the rotor 4 cannot be obtained.

Furthermore, in the case of the point pressurization described with reference to FIG. 5, the support rigidity for holding the posture of the vibrator 3 when the frictional driving force acts on the contact surface of the rotor 4 is very small. For this reason, the vibrator 3 easily tilts or falls with respect to the frictional sliding surface of the rotor 4, so that the contact state between the convex portion 1d and the rotor 4 becomes unstable, and as a result, the output decreases. End up.

In order to solve such a problem, in the first embodiment, the upper surface of the vibrator 3 (upper surface of the piezoelectric element 2) is surface-added with the lower surface (contact portion) of the pressing member 5 arranged in parallel with the rotor 4. A structure is adopted in which the posture of the vibrator 3 is stabilized by following the lower surface of the pressure member 5 by applying pressure. Below, the advantage of this structure is demonstrated.

As shown in FIG. 1A, in the vibration type actuator 100, three drive units 200 are arranged at equal intervals on the circumference of the rotor 4 which is a single member, and the upper surface of each vibrator 3 (opposite to the convex portion 1d). The pressure member 5 which is an annular single member is disposed so as to abut on the upper surface of the piezoelectric element 2 on the side. Here, since the dimensions of each vibrator 3 (distance from the tip surface of the convex portion 1d to the top surface of the piezoelectric element 2) are controlled to be the same, they contact the top surface of each vibrator 3. The pressed member 5 is parallel to the frictional sliding surface of the rotor 4. The pressurizing member 5 is made of a material such as a resin so as not to prevent the vibration excited by the vibrator 3 in a state of being in contact with the entire upper surface of the piezoelectric element 2.

When the vibrator 3 is pressed against the rotor 4 by the pressure spring 9 in this state, the convex portion 1d is applied from the entire upper surface of the piezoelectric element 2 having substantially the same area as the diaphragm main body portion 1a of the diaphragm 1. The pressure abuts against the frictional sliding surface of the rotor 4. At this time, the posture of the vibrator 3 is stabilized by being regulated so that the upper surface of the piezoelectric element 2 follows the contact surface with the pressing member 5. As a result, the vibrator 3 can be maintained in a state parallel to the frictional sliding surface of the rotor 4, and the support rigidity in the Rx direction and the Ry direction shown in FIG. 5 can be increased. Therefore, even if a large reaction force is applied to the vibrator 3 by reversal or the like when the rotor 4 is driven, the contact between the convex portion 1d and the rotor 4 does not become unstable, and a stable output can be obtained.

In the first embodiment, the rotor 4 is described as rotating. However, the present invention is not limited to this. For example, the rotor 4 is fixed to an external member and the fixing member 8 provided with the vibrator 3 is rotated. Also good. Further, although the vibration type actuator 100 is configured to include the three vibrators 3, the configuration is not limited thereto, and may be configured to include one or a plurality of vibrators 3.

Next, a second embodiment of the present invention will be described. Compared with the vibration type actuator 100 according to the first embodiment, the vibration type actuator according to the second embodiment uses a pressure member 15 described below instead of the pressure member 5 constituting the vibration type actuator 100. Is different. The components of the vibration type actuator according to the second embodiment other than the pressure member 15 are the same as the components of the vibration type actuator 100. Therefore, in the following description, it demonstrates centering on the effect obtained by using the structure of the pressurization member 15, and the pressurization member 15, and abbreviate | omits description about the already demonstrated common component.

FIG. 7A is a front view showing a schematic structure of a drive unit 200A constituting the vibration type actuator according to the second embodiment of the present invention, and is drawn from the same viewpoint as FIG. 1B. FIG. 7B is a top view (plan view) schematically showing a contact state of the pressing member 15 with respect to the vibrator 3.

Two protrusions 15 a that abut on the piezoelectric element 2 in the contact area A (shaded area) at the longitudinal end of the piezoelectric element 2 are formed in a portion of the pressure member 15 that faces the vibrator 3. Since the three drive units 200A are arranged with respect to the pressure member 15 (see FIG. 1A), the protrusions 15a are provided at six locations in the entire pressure member 15. Thus, by making the contact area between the vibrator 3 and the pressure member 15 as small as possible, it is possible to prevent the vibration of the vibrator 3 from being hindered by the material constituting the pressure member 15.

Further, the portion where the convex portion 1d of the vibrator 3 is in contact with the rotor 4 has a structure that is located inside the contact region A, which is the portion where the pressing member 5 contacts the vibrator 3, in the driving direction. . Thereby, the posture of the vibrator 3 when the vibrator 3 is pressed against the rotor 4 can be set to a more stable posture.

FIG. 8 is a diagram illustrating a state where the vibrator 3 is pressed against the rotor 4 in the drive unit 200A. FIG. 8A is a top view similar to FIG. 7B, and is a diagram for explaining the relationship between the contact region A where the pressing member 15 contacts the vibrator 3 and the structure of the vibrator 3. FIG. 8B is a side view showing a state where the pressing member 15 presses the vibrator 3 against the rotor 4 in an ideal state. FIG. 8C is a side view schematically showing a contact state between the vibrator 3 and the rotor 4 when it is assumed that the pressure member 15 and the rotor 4 are not installed in parallel.

As shown in FIG. 8A, the region having the largest area among the regions formed by connecting the two contact regions A, which are portions where the protrusions 15a of the pressing member 15 are in contact with the vibrator 3 (piezoelectric element 2). The outermost contour (first region) is defined as a pressure application region B. The pressure application region B is a region where the pressure applied from the pressure member 15 by the pressure spring 9 acts on the vibrator 3. Further, the outermost contour (second region), which is the region having the largest area among the regions formed by connecting the contact portions with the rotor 4 in the convex portion 1 d of the vibrator 3, is defined as the drive contact region C. . In the second embodiment, the first area is set to be larger than the second area, and as a more preferable form, the drive contact area C is set to be located inside the pressurizing action area B. ing.

This is an indispensable condition for causing the posture of the vibrator 3 to follow the pressing member 15. That is, in the vibration type actuator according to the second embodiment, as shown in FIG. 8B, it is desirable that the pressure member 15, the vibrator 3, and the rotor 4 are kept in a parallel posture. That is, the entire tip surface of the convex portion 1d of the vibrator 3 is in uniform contact with the friction surface of the rotor 4, and at the same time, the whole tip surface of the protrusion 15a of the pressure member 15 is in contact with the upper surface of the vibrator 3 (piezoelectric element 2). It is desirable to be in a state of even contact. However, since the postures of the pressure member 15 and the rotor 4 are determined individually, it is rare that the pressure member 15, the vibrator 3, and the rotor 4 are assembled so as to be naturally parallel. Therefore, it is necessary to hold the vibrator 3 having a degree of freedom of inclination in a calm state in a posture that follows either the pressure member 15 or the rotor 4.

Therefore, as shown in FIGS. 8A and 8B, the pressure W is larger when the width W2 of the pressure application region B is larger than the width W1 of the drive contact region C and the pressure applied by the pressure spring 9 is applied. The shape design is made so that the action area B completely encompasses the drive contact area C. As a result, even if the vibrator 3 is inclined so as to follow the friction surface of the rotor 4 because the pressurizing member 15 and the rotor 4 are not installed in parallel, as shown in FIG. A rotational moment of F4 × L acts on the Q point. As a result, the vibrator 3 becomes stable in a posture following the pressure member 15. In the opposite case (when the vibrator 3 is inclined so as to follow the contact surface with the pressure member 15 (first region: contact region A), and a concentrated load is applied to the point Q on the drive contact region C side. Etc.) does not generate a rotational moment that tilts the vibrator 3.

When the vibrator 3 is sandwiched between two members (the rotor 4 and the pressure member 15) and the posture is determined, the contact area with the side to which the posture of the vibrator 3 is to be copied is widened and viewed from the pressure direction. So that the contact area on the other side is completely included. Thereby, the vibrator 3 can be made to follow the intended surface. The same applies to the driving direction of the rotor 4. When viewed in a plan view, the pressurizing action region B is set so as to completely include the driving contact region C as shown in FIG. 8A.

In addition, by setting it as the structure where the gravity center of the pressurization action area | region B is located in the inside of the drive contact area C like 2nd Embodiment, the effect which imitates the surface of the said vibrator | oscillator 3 to the intended side is produced. It can be obtained more effectively. In the second embodiment, the vibrator 3 is in contact with the rotor 4 at two circular positions (tip surfaces of the convex portions 1d at two positions). It is not limited. Further, the number and shape of the contact surfaces of the pressing member 15 with respect to the vibrator 3 may be any as long as the relationship between the pressurizing action region B and the driving contact region C is established, and is limited to the above configuration. It is not a thing.

Next, a third embodiment of the present invention will be described. The vibration type actuator according to the third embodiment is different from the vibration type actuator 100 according to the first embodiment in that a support member 16 described below is used instead of the support member 6 constituting the vibration type actuator 100. ing. The constituent elements of the vibration type actuator according to the third embodiment other than the support member 16 are the same as the constituent elements of the vibration type actuator 100. Therefore, hereinafter, the description will be focused on the structure of the support member 16 and the effects obtained by using the support member 16, and description of the common components already described will be omitted.

9A is a front view showing a state in which the vibrator 3 is joined to the support member 16 constituting the vibration type actuator according to the third embodiment of the present invention, and FIG. 9B is a perspective view showing the structure of the support member 16. It is. The support member 16 includes an attachment portion 16a, a support portion 16b, a support arm portion 16c, and a screw hole 16d, which are respectively the attachment portion 6a, the support portion 6b, and the support arm of the support member 6 described in the first embodiment. It corresponds to the part 6c and the screw hole 6d.

The difference between the support member 16 and the support member 6 used in the first embodiment is the shape of a screw hole for attachment to the fixing member 8. In other words, the screw hole 6 d of the support member 6 is a round hole, whereas the screw hole 16 d of the support member 16 is a long hole that is long in a direction parallel to the direction in which the vibrator 3 is pressed against the rotor 4. Accordingly, when the vibrator 3 integrally joined to the support member 16 is assembled and fixed in the drive unit, the position of the vibrator 3 can be adjusted in a direction in which the vibrator 3 is pressed against the rotor 4.

For example, for the components constituting the vibration type actuator 100, the thickness of the rotor 4 varies, the position error of the screw hole 6 d of the support member 6, the position error of the screw hole provided in the fixing member 8, etc. "). Therefore, in the vibration type actuator 100, when the vibrator 3 is incorporated into the drive unit 200, there is a possibility that the assembling position of the vibrator 3 with respect to the friction surface of the rotor 4 may vary due to dimensional variations. Therefore, in the first embodiment, the support portion 6b of the support member 6 is designed to bend and absorb the dimensional variation so that the applied pressure that presses the vibrator 3 against the rotor 4 is not affected. On the other hand, the third embodiment aims to eliminate the influence of dimensional variations as much as possible.

The assembly of the drive unit using the support member 16 is performed as follows. First, a predetermined number of balls 7 are arranged at substantially equal intervals in the circumferential direction in the V groove formed in the flange portion 8 b of the fixing member 8, and the rotor 4 is arranged so that the balls 7 come into contact with the V groove formed in the rotor 4. Put it on. The vibrator 3 and the support member 16 are joined in advance by welding or the like, and the vibrator 3 and the support member 16 are installed so that the front end surface of the convex portion 1 d of the vibrator 3 is in contact with the friction surface of the rotor 4. At this time, the support member 16 is roughly aligned and temporarily fixed with the screw 11. Next, the pressure member 5 is placed on the upper surface of the piezoelectric element 2 of the vibrator 3, and the pressure spring 9 and the spring holding member 10 are installed to apply pressure to the vibrator 3. In this state, the screw 11 temporarily fixed is loosened, and the position of the support member 16 is readjusted so that the support member 16 (support portion 16b) is not bent. Then, the screw 11 is retightened to firmly fix the support member 16.

As a result, unnecessary bending of the support member 16 that occurs when the drive unit is assembled can be almost eliminated, and unevenness in the pressure applied to the rotor 4 of each vibrator 3 due to component accuracy can be avoided. Can do. In this way, stable driving performance can be obtained.

Next, a fourth embodiment of the present invention will be described. The vibration type actuator according to the fourth embodiment is different from the vibration type actuator 100 according to the first embodiment in that the vibration type actuator 100 includes an insulating member 12 described below which is not included in the vibration type actuator 100. The components of the vibration type actuator according to the fourth embodiment other than the insulating member 12 are the same as those of the vibration type actuator 100. Therefore, hereinafter, the description will be focused on the structure of the insulating member 12 and the effects obtained by using the insulating member 12, and description of common components will be omitted.

FIG. 10A is a front view showing a schematic structure of a drive unit 200B constituting a vibration type actuator according to a fourth embodiment of the present invention, and FIG. 10B is a cross-sectional view of the drive unit 200B. The drive unit 200B has an insulating member 12 disposed between the vibrator 3 and the pressure member 5, and the other constituent members are the same as those of the drive unit 200 described in the first embodiment. is there.

In the first embodiment, the pressing member 5 made of resin or the like is in direct contact with the upper surface of the piezoelectric element 2 of the vibrator 3. On the other hand, the fourth embodiment aims to enable the posture of the vibrator 3 to be maintained without impeding the vibration of the vibrator 3 without limiting the material constituting the pressure member 5. Therefore, the insulating member 12 is made of a material that can maintain a contact state without restricting the vibration of the vibrator 3, and specifically, felt, malt plane, or the like is used.

Since the insulating member 12 is installed in a compressed state between the pressure member 5 and the vibrator 3, the elastic modulus in the thickness direction is an initial value (elastic modulus in a state before being incorporated in the drive unit 200B). Higher than. Therefore, the rigidity for supporting the vibrator 3 from the piezoelectric element 2 side can be increased. Thereby, even if the insulating member 12 is arranged, a holding structure that does not hinder the vibration of the vibrator 3 without impairing the posture holding ability of the vibrator 3 by the pressure member 5 can be realized.

Next, a fifth embodiment of the present invention will be described. The vibration type actuator according to the fifth embodiment differs from the vibration type actuator 100 according to the first embodiment in place of the pressure member 15 and the vibrator 3 of the vibration type actuator 100, and a pressure member 25 described below and The difference is that a vibrator 23 is provided. The components of the vibration type actuator according to the fifth embodiment other than the pressure member 25 and the vibrator 23 are the same as the components of the vibration type actuator 100. Therefore, hereinafter, the structure of the pressure member 25 and the diaphragm 21 and the effects obtained by using the pressure member 25 and the vibrator 23 will be mainly described, and description of common components will be omitted.

FIG. 11A is a front view showing a partial structure of the pressure member 25 constituting the vibration type actuator according to the fifth embodiment of the present invention. 11B, 11C, and 11D are a plan view, a side view, and a front view, respectively, showing a schematic structure of the vibrator 23 that constitutes the vibration type actuator according to the fifth embodiment of the present invention. The fifth embodiment is characterized in that a portion that restrains the posture of the vibrator 23 by the pressure member 25 is a node common to a plurality of vibration modes excited by the vibrator 23.

The diaphragm 21 constituting the vibrator 23 has a diaphragm main body 21a and a diaphragm arm 21b extending to the longitudinal end of the diaphragm main body 21a. The vibrator 23 is designed such that the fifth-order out-of-plane bending vibration mode M1 and the second-order out-of-plane bending vibration mode M2 are excited. Therefore, the longitudinal length of the diaphragm body 21a is longer than the longitudinal length of the diaphragm body 1a of the diaphragm 1 described in the first embodiment, and the shape of the piezoelectric element 22 is also the diaphragm. In accordance with the shape of the main body 21a, the rectangular shape is set in plan view.

As shown in FIGS. 11B to 11D, in the vibration mode M1, five nodes (node line Nm ₁ ) are formed, and in the vibration mode M2, two nodes (node line Nm ₂ ) are formed. The portions where these nodal lines intersect (nodes Nm ₁₂ ) are formed at 10 locations, and no vibration displacement appears at these 10 nodes Nm _{12 even} if the vibration modes M1 and M2 are excited simultaneously. Therefore, even if the pressing member 25 is pressed against the node Nm _12, there is no substantial influence on the vibration of the vibrator 23.

Accordingly, among the ten nodes Nm12, four points that maximize the pressure application region described in the second embodiment are selected, and these four points are used as a pressure application region D that contacts the pressure member 25. . For this purpose, as shown in FIG. 11A, four protrusions that contact the piezoelectric element 22 in the pressure application region D at the longitudinal end of the piezoelectric element 22 are formed on the portion of the pressing member 25 facing the vibrator 3. 25a is formed. In the vibration type actuator according to the fifth embodiment as well, since the pressure member 25 is a single member, there are 12 protrusions 25 a corresponding to the three vibrators 23 in the entire pressure member 25. Has been. According to the fifth embodiment, the vibrator 23 can be held so as to follow the pressure member 25 without affecting the vibration of the vibrator 23.

Next, a sixth embodiment of the present invention will be described. In the first to fifth embodiments described above, the vibration type actuator according to the present invention is embodied as a rotary drive device that rotates the rotor 4. On the other hand, the vibration type actuators according to the sixth embodiment and the seventh embodiment described later are realized as a linear drive device that reciprocates the slider, which is a driven body, in a linear direction. .

12A and 12B are a plan view and a front view showing a schematic structure of a vibration type actuator 100A according to a sixth embodiment of the present invention, respectively. The basic structure of the vibration type actuator 100A is the same as that of the first embodiment. The fixing member 38 constituting the vibration type actuator 100 </ b> A has a bottom wall part 38 a and a side wall part 38 b, has a U-shaped cross section, and has a substantially rectangular parallelepiped shape that is long in the X direction that is the driving direction of the slider 34. Each of the four vibrators 33 is joined to a support member 36 equivalent to the support member 6, and each of the four support members 36 is fixed to the side wall portion 38 b of the fixing member 38. For example, the vibrator 33 is equivalent to the vibrator 23 described in the fifth embodiment.

The slider 34 has a substantially rectangular parallelepiped shape that is long in the X direction, which is the driving direction, and is in contact with the bottom wall portion 38 a of the fixing member 38 via a plurality of balls 37. Each of the plurality of balls 37 is sandwiched between V-grooves (not shown) extending in the X direction formed on the upper surface of the bottom wall portion 38a of the fixing member 38 and the surface of the slider 34 on the bottom wall portion 38a side. ing. Thus, by forming a rolling bearing, the slider 34 can move in the X direction which is the driving direction. The pressure spring 39 is held by the spring holding member 40 and abuts against the upper surface of the piezoelectric element 22 via the pressure member 35, thereby pressing the vibrator 33 against the slider 34. In FIG. 12A, the spring holding member 40 and the pressure spring 39 are not shown, and the spring holding member 40 and the pressure member 35 are indicated by broken lines.

The dimensions of the four vibrators 33 (the thickness from the contact surface with the slider 34 to the contact surface with the pressure member 35) are controlled so as to be the same. Therefore, the pressure member 35 that is in contact with the piezoelectric element constituting the vibrator 33 is maintained in a state substantially parallel to the friction surface of the slider 34. Therefore, the vibrator 33 whose posture is constrained by the pressure member 35 can also maintain the posture parallel to the slider 34, thereby realizing a stable contact state and obtaining stable driving characteristics. . Here, although the vibration type actuator is configured by the four vibrators 33, the number of the vibrators 33 is not limited to this.

Next, a seventh embodiment of the present invention will be described. The vibration type actuator according to the seventh embodiment includes a pressure member 45 in which the shape of the pressure member 35 constituting the vibration type actuator 100A according to the sixth embodiment is changed. The components of the vibration type actuator according to the seventh embodiment other than the pressure member 45 are the same as the components of the vibration type actuator 100A according to the sixth embodiment. Therefore, hereinafter, the description will be focused on the pressure member 45 and the effects obtained by using the pressure member 45, and the description of the common components will be omitted.

13A, 13B, and 13C are a plan view, a front view, and a partial cross-sectional view showing a schematic structure of a vibration type actuator 100B according to a seventh embodiment of the present invention, respectively. As shown in FIG. 13C, the pressing member 45 is provided with a protrusion 45 a serving as a contact portion with the vibrator 33. One protrusion 45 a is provided for each transducer 33 so as to contact the vicinity of the center of the piezoelectric element of each transducer 33. Here, the protrusion 45 a has a short width in the X direction that is the driving direction of the slider 34, while it is almost the same as the width of the vibrator 33 in the Y direction that is the width direction of the vibrator 33 orthogonal to the X direction. Designed to dimensions.

That is, the pressure application region in which the pressing member 45 abuts on the vibrator 33 to apply the pressure is in the vicinity of the center of the vibrator 33 in the driving direction (X direction) of the slider 34. At the same time, the pressure application region of the pressing member 45 is such that the convex portion of the vibrator 33 that contacts the slider 34 is perpendicular to both the driving direction of the slider 34 and the direction in which the vibrator 33 is pressed against the slider 34. It is wider than the area.

Thus, the posture of the vibrator 33 is restricted following the pressure member 45 only with respect to the inclination in the width direction (roll direction), but with respect to the inclination (pitching) in the driving direction, the slider 34 Has the freedom to follow the friction surface. Such a structure is a vibration type actuator in which the driving reaction force applied to the vibrator 33 and the external force transmitted from the slider 34 are relatively small, and the influence of these forces is small in stabilizing the posture of the vibrator 33. It is very effective for this. Note that the structure of the pressing member 45 is not limited to the linear drive device as in the present embodiment, but can also be applied to the rotary drive device described in the first embodiment.

Next, an eighth embodiment of the present invention will be described. In the eighth embodiment, an example in which various vibration actuators according to the above-described embodiments of the present invention are applied to an imaging apparatus will be described. FIG. 14 is a top view illustrating a schematic configuration of the imaging apparatus 80 according to the embodiment of the present invention. The imaging device 80 includes a camera body 83 and a lens barrel 87. The camera body 83 includes a power button 81 and an image sensor 82 that converts an optical image formed by the light passing through the lens barrel 87 into an electrical signal. The lens barrel 87 includes a lens 84 and a vibration type actuator 85 having a drive unit 86. The vibration type actuator 85 and the drive unit 86 are, for example, the vibration type actuator 100 and the drive unit 200 described in the first embodiment, respectively.

The lens barrel 87 can be replaced with the camera body 83 as an interchangeable lens, and a lens barrel 87 suitable for the subject to be photographed can be attached to the camera body 83. The lens 84 is, for example, a zoom lens that changes the imaging angle of view, or a focus lens that focuses on the subject. In the imaging device 80, three (one not shown) drive units 86 drive a driven body (not shown), and the driven body drives a gear or a cam to hold the lens 84 (not shown). The holding member is moved in the optical axis direction. As a result, a highly reliable imaging device 80 capable of stable lens driving can be realized.

The driving unit 86 can also be used to drive an image blur correction lens for correcting image blur of an optical image formed on the image sensor 82. In this case, for example, the image blur correcting lens may be arbitrarily moved in each of two orthogonal directions within a plane orthogonal to the optical axis using two drive units 86. Further, in order to correct image blur, instead of the image blur correction lens, the image sensor 82 may be arbitrarily moved in each of two orthogonal directions within a plane orthogonal to the optical axis.

Next, a ninth embodiment of the present invention will be described. In the ninth embodiment, an example in which various vibration actuators according to the above-described embodiments of the present invention are applied to an automatic stage will be described. FIG. 15 is an external perspective view of a microscope 90 having an automatic stage 96 according to the embodiment of the present invention. The microscope 90 includes an image pickup unit 92 including an image pickup element and an optical system, and an automatic stage 96 having a stage 94 moved in the XY plane. Although the detailed configuration of the automatic stage 96 is not shown, the automatic stage 96 includes at least two drive units that drive the stage 94 as a driven body. At least one drive unit is used for driving the stage 94 in the X direction, and at least one other drive unit is used for driving the stage 94 in the Y direction.

The object to be observed is placed on the stage 94 and an enlarged image is taken by the imaging unit 92. When the observation range is wide, the automatic stage 96 is driven to move the observation object in the X direction or the Y direction to move the observation object, thereby acquiring a large number of captured images. By combining the captured images by image processing with a computer (not shown), it is possible to acquire a single image with a wide observation range and high definition.

Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. Furthermore, each embodiment mentioned above shows only one embodiment of this invention, and it is also possible to combine each embodiment suitably.

DESCRIPTION OF

SYMBOLS

1,21

Diaphragm

2,22

Piezoelectric element

3,23 Vibrator 4 Rotor (driven body)
5, 15, 25, 35

Pressure member

6, 16, 36

Support member

7, 37

Ball

8, 38 Fixing

member

9, 39

Pressure spring

10, 40 Spring holding member 80 Imaging device 96

Automatic stage

100, 100A, 100B

Vibration Type actuator

200, 200B Drive unit

Claims

An electro-mechanical energy conversion element, and a vibrator having an elastic body to which the electro-mechanical energy conversion element is bonded;
A driven body that comes into contact with a driving unit provided in the vibrator;
A pressure member that supports the vibrator, and comprises a pressure unit that presses the vibrator against the driven body by pressing the pressure member against the vibrator,
The vibrator and the driven body are configured such that a relative position between the vibrator and the driven body is changed by vibration excited by the vibrator,
In a plane including a direction in which the relative position changes and a pressurizing direction in which the pressurizing unit presses the vibrator against the driven body, the vibrator is positioned more toward the pressurizing member than the driven body. A vibration type actuator characterized by being configured to follow.
An electro-mechanical energy conversion element, and a vibrator having an elastic body to which the electro-mechanical energy conversion element is bonded;
A driven body that comes into contact with a driving unit provided in the vibrator;
A pressure member that supports the vibrator, and comprises a pressure unit that presses the vibrator against the driven body by pressing the pressure member against the vibrator,
The vibrator and the driven body are configured such that a relative position between the vibrator and the driven body is changed by vibration excited by the vibrator,
The pressurizing member has one or a plurality of portions in contact with the vibrator,
The vibrator has one or more portions in contact with the driven body,
A region where the pressurizing member abuts against the vibrator or a plurality of the pressurizing members abuts against the vibrator when viewed from the pressurizing direction in which the pressurizing unit presses the vibrator against the driven body The region having the largest area among the regions formed by connecting the portions is defined as a first region, and a region where the vibrator contacts the driven body or a plurality of portions where the vibrator contacts the driven body When the region having the largest area among the regions formed by connecting the portions is the second region, the first region is larger than the second region,
The vibration type wherein the first region and the second region overlap at least partially when viewed from the pressurizing direction so that the vibrator and the driven body do not rotate. Actuator.
3. The vibration type actuator according to claim 2, wherein a center of the second region is located inside the first region when viewed from the pressurizing direction.
4. The vibration type actuator according to claim 2, wherein the second region is inside the first region when viewed from the pressurizing direction.
The region formed by connecting the plurality of portions where the pressure member abuts on the vibrator is in the vicinity of the center in the direction in which the relative position of the vibrator changes. The vibration type actuator according to any one of the above.
The at least part of a region formed by connecting a plurality of portions where the pressing member is in contact with the vibrator is provided at a node of vibration excited by the vibrator. 6. The vibration type actuator according to any one of 2 to 5.
An electro-mechanical energy conversion element, and a vibrator having an elastic body to which the electro-mechanical energy conversion element is bonded;
A driven body that comes into contact with a driving unit provided in the vibrator;
A pressure member that supports the vibrator, and comprises a pressure unit that presses the vibrator against the driven body by pressing the pressure member against the vibrator,
The vibrator and the driven body are configured such that a relative position between the vibrator and the driven body is changed by vibration excited by the vibrator,
When the vibrator is supported by the pressurizing unit without contacting the driven body, a surface of a portion where the vibrator receives a force from the pressurizing unit is defined as a first surface.
When the vibrator is supported by the driven body without coming into contact with the pressurizing means, a surface of a portion where the vibrator receives a force from the driven body is a second surface,
The absolute value of the rotational moment about the centroid of the second surface due to the reaction force acting on the first surface when a force perpendicular to the first surface is applied to the second surface. Let the sum be the first moment,
The first force due to a reaction force acting on the second surface when a force perpendicular to the second surface is equal in magnitude to the force perpendicular to the first surface and acting on the first surface. When the sum of absolute values of rotational moments centered on the centroid of the surface is the second moment,
In the plane including the direction in which the relative position changes and the pressurizing direction in which the pressurizing unit presses the vibrator against the driven body, the vibrator, the driven body, and the pressurizing means include the first A vibration type actuator configured so that one moment is larger than the second moment.
In the vibrator, the driven body, and the pressurizing unit, the first moment is larger than the second moment in a plane including a direction orthogonal to the direction in which the relative position changes and the pressurizing direction. The vibration type actuator according to claim 7, wherein the vibration type actuator is configured as described above.
The portion where the vibrator contacts the driven body when viewed from the pressurizing direction is inside the portion where the pressurizing member contacts the vibrator. The vibration type actuator described in 1.
10. The vibration type actuator according to claim 1, further comprising a support member that supports the vibrator from the same direction as the pressure member.
The support member has two joint portions to be joined to the vibrator, and the two joint portions are configured such that rigidity in a direction in which the relative position changes is larger than rigidity in the pressurizing direction. The vibration type actuator according to claim 10, wherein the vibration type actuator is provided.
The vibration type actuator according to claim 10 or 11, further comprising a fixing member to which the support member is fixed.
The support member has a substantially L-shaped cross-sectional shape, and an attachment hole for fixing the support member to the fixing member is provided on one surface attached to the fixing member.
The mounting hole is a long hole extending in a direction parallel to the pressing direction, and the mounting position of the support member relative to the fixing member can be adjusted when the supporting member is mounted on the fixing member. The vibration type actuator according to claim 12, wherein
The elastic body is composed of a main body having a longitudinal direction in which the electromechanical energy conversion element is bonded and the relative position is changed, and an arm extending to a longitudinal end of the main body.
The drive unit is provided on a surface opposite to a surface to which the electro-mechanical energy conversion element is bonded in the main body,
The support member has a substantially L-shaped cross-section in a plane perpendicular to the direction in which the relative position changes, and the tip of one surface that is substantially parallel to the friction surface of the driven body has two support arms. Divided into parts,
The vibration type actuator according to any one of claims 10 to 13, wherein the arm portion of the elastic body is joined to the support arm portion.
A plurality of the vibrators,
15. The vibration type actuator according to claim 1, wherein the pressure member is a single member that contacts the plurality of vibrators.
The vibration type actuator according to any one of claims 1 to 15, further comprising an insulating member disposed between the pressurizing member and the vibrator.
The vibration type actuator according to claim 16, wherein the insulating member is compressed and held between the pressure member and the vibrator.
The pressure member is in contact with the electromechanical energy conversion element;
The said drive part is provided in the surface of the said elastic body on the opposite side to the surface where the said electromechanical energy conversion element is joined, The any one of Claim 1 thru | or 17 characterized by the above-mentioned. Vibration type actuator.
A lens,
A lens barrel comprising: the vibration type actuator according to claim 1, wherein the lens is moved in an optical axis direction.
An image blur correction lens,
19. A lens barrel comprising: the vibration type actuator according to claim 1, wherein the image blur correcting lens is moved in a plane orthogonal to an optical axis direction.
A lens barrel;
The vibration type actuator according to any one of claims 1 to 18, wherein a lens disposed in the lens barrel is moved in an optical axis direction.
An imaging device comprising: an imaging device that converts an optical image formed by light passing through the lens barrel into an electrical signal.
A lens barrel;
An image sensor that converts an optical image formed by the light passing through the lens barrel into an electrical signal;
The vibration type actuator according to any one of claims 1 to 18, wherein the vibration type actuator for correcting an image blur of the optical image formed on the image pickup device by moving the image pickup device in a plane orthogonal to an optical axis direction; An imaging apparatus comprising:
Stage,
An automatic stage comprising: the vibration type actuator according to any one of claims 1 to 18, wherein the stage is moved in a plane thereof.