JP2013179733A - Vibrating body holding mechanism, ultrasonic motor, and lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrating body holding mechanism which properly holds a vibrating body while preventing the occurence of resonance due to vibrations of the vibrating body and generates stable vibrations to the vibrating body, and to provide an ultrasonic motor and a lens driving device.SOLUTION: A vibrating body holding mechanism includes a vibrating body and a holding member housing and holding the vibrating body so that the vibrating body may vibrate, and outputs a vibrating force of the vibrating body to the exterior. In the vibrating body holding mechanism, the vibrating body includes: a prismatic trunk part housed in the holding member; and a vibration output part provided at the one end side of the trunk part so as to protrude to the outer side of the holding member. The holding member includes: a vibrating body housing part formed by a wall surface placed along four side surfaces forming the trunk part of the vibrating body so as to be spaced a predetermined distance away from the four side surfaces and be arranged in parallel with the four side surfaces; and resonance prevention means located on an inner surface of the wall surface forming the vibrating body housing part and inhibiting vibrations of the vibrating body from being transmitted to the wall surface. In order to achieve the above object, the vibrating body holding mechanism is adopted.

Description

  The present invention relates to a vibrating body holding mechanism that holds a vibrating body of an ultrasonic motor.

  The ultrasonic motor generates one specific ultrasonic vibration or two different specific ultrasonic vibrations at a predetermined frequency and timing in the vibration body, so that a rotational motion such as an ellipse is generated at the vibration output unit of the vibration body. Or a reciprocating motion is generated, and this motion is transmitted to a driven body such as a rotor brought into contact with the vibration output section to drive the driven body. The ultrasonic motor can realize low speed and high torque, is excellent in quietness, and is suitable for reduction in size and weight. For this reason, it is widely used as a drive source for various movable mechanisms that require precise positioning, such as a camera autofocus function and a scanning electron microscope.

  The vibrating body of the ultrasonic motor is held by a holding member or the like in a state where fine vibration is possible so that the vibration of the vibrating body is not easily transmitted to surrounding members such as the base member of the ultrasonic motor. As a method of holding the vibrating body, for example, the vibration motor unit disclosed in Patent Document 1 proposed by the present applicant is a vibrator holder (vibrating body holder) made of a member different from the base member of the vibration motor. The structure which holds a vibration body is employ | adopted. Specifically, in Patent Document 1, the vibrator can be expanded and contracted and vibrated in a desired direction in a state in which the vibrator is housed in the housing portion of the vibrator holder formed of a frame having a groove-shaped housing portion. It is held.

  Further, Patent Document 2 discloses a configuration in which a support member is provided in the vicinity of the top surface of the vibration body and the position of the node of the vibration body, and the vibration body of the piezoelectric motor is held by pressurizing the vibration body with the support member. ing.

JP 2010-206907 A Japanese Patent No. 4878378

  However, in the configuration of Patent Document 1, a slight gap is generated between the holding portion of the vibrating body holder and the vibrating body due to variations in component accuracy, and the vibration unevenness of the vibrating body is suppressed by the holding portion. May not be possible. Moreover, in the structure of patent document 2, since a vibrating body is compressed by the pressurization by a holding member, the frictional force between a vibrating body and the friction member located in the lower surface of the said vibrating body increases. As a result, when the vibration is applied to the vibrating body, the slip between the vibrating body and the friction member is suppressed, and there is a possibility that the vibration that leads to a desired motion in the vibration output portion of the vibrating body may be inhibited. Furthermore, as described above, the slip between the vibrating body and the friction member is suppressed, so that the vibration of the vibrating body is easily transmitted to surrounding members such as the friction member and the base member. As a result, the vibration of the vibrating body is amplified and transmitted to surrounding members such as the friction member and the base member, and these friction members and the base member may resonate.

  Accordingly, the present invention provides a vibrating body holding mechanism, an ultrasonic motor, and a lens driving device capable of appropriately holding the vibrating body and generating stable vibration in the vibrating body while preventing the occurrence of resonance due to vibration of the vibrating body. The purpose is to provide.

  As a result of intensive studies, the present inventors have achieved the above object by employing the following vibrating body holding mechanism, ultrasonic motor, and lens driving device.

  The vibrating body holding mechanism according to the present invention is a vibrating body holding mechanism including a vibrating body and a holding member that houses and holds the vibrating body in a freely oscillating manner, and the vibrating body is housed in the holding member. And a vibration output portion provided on one end side of the body portion and projecting outside the holding member. The holding member constitutes the body portion of the vibration body. The vibration body accommodating portion constituted by wall surfaces arranged in parallel at predetermined intervals along the four side surfaces, and the vibration generated by the vibration body on the inner surface of the wall surface constituting the vibration body accommodating portion Resonance prevention means for suppressing transmission to the wall surface is provided.

  In the vibrating body holding mechanism according to the present invention, the resonance preventing means includes a recess on one inner wall surface of the pair of opposed inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member, It is preferable that an elastic member is disposed in the recess, a recess is provided on the other inner wall surface, and a rolling element is disposed in the recess.

  In the vibrating body holding mechanism according to the present invention, the resonance preventing means includes a recess on one inner wall surface of the pair of opposed inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member, It is also preferable that an elastic member and a rolling element are provided in this recess, a recess is provided on the other inner wall surface, and the rolling element is provided in this recess.

  In the vibrating body holding mechanism according to the present invention, the resonance preventing means includes a recess on one inner wall surface of the pair of opposed inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member, It is also preferable that an elastic member and a rolling element are disposed in the recess, a recess is provided on the other inner wall surface, and the elastic member and the rolling element are disposed in the recess.

  The vibrating body holding mechanism according to the present invention preferably uses a conical spring material as the elastic member.

  The ultrasonic motor according to the present invention uses the above-described vibrating body holding mechanism, and the prism-shaped vibrating body has the other end for pressing the vibration output portion provided on the one end side to the driven body. An urging means for pressing the side surface against the one end side is provided.

  A lens driving device according to the present invention is a lens driving device of an imaging apparatus, and is characterized by using the above-described ultrasonic motor.

  The vibrating body holding mechanism according to the present invention is provided with a resonance preventing unit that suppresses vibration generated by the vibrating body from being transmitted to the wall surface on the inner surface of the wall surface that constitutes the vibrating body housing portion. It can be kept in an appropriate state. In particular, it is possible to effectively prevent inconvenience that the vibration of the vibrating body is transmitted to the wall surface of the vibrating body housing portion by the resonance preventing means. As a result, the vibration of the vibrating body is amplified and transmitted via the vibrating body holding mechanism to the base member on which the vibrating body holding mechanism is mounted, the surrounding members provided on the base member, and the like. The problem of resonating and adversely affecting the driving of the ultrasonic motor can be prevented.

  Since the ultrasonic motor according to the present invention includes a vibrating body holding mechanism that can hold the vibrating body in an appropriate state while preventing the occurrence of resonance caused by the vibration of the vibrating body as described above, An ultrasonic motor having no vibration unevenness and high driving efficiency can be provided. In addition, since the lens driving device according to the present invention includes the above-described ultrasonic motor with high driving efficiency, it is possible to realize highly accurate lens movement control while reducing power consumption.

It is a top view which shows one Embodiment of the vibrating body holding mechanism which concerns on this invention. It is a schematic diagram which shows the shape of a vibrating body. It is a figure which shows the state which looked at the cross section in the AA of the vibrating body holding | maintenance mechanism of FIG. 1 from the arrow direction. It is a schematic diagram which shows the outer shape of an elastic member. It is a figure which shows the example of arrangement | positioning of the rolling element of a cylindrical body. It is a schematic diagram which shows the shape of a vibrating body holding mechanism. It is another schematic diagram which shows the shape of a vibrating body holding | maintenance mechanism. It is another schematic diagram which shows the shape of a vibrating body holding member.

  Hereinafter, preferred embodiments of a vibrating body holding mechanism, an ultrasonic motor, and a lens driving device according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the illustrated form.

  The vibrating body holding mechanism according to the present invention is a mechanism for holding the vibrating body of the ultrasonic motor. The ultrasonic motor generates a motion in the vibration output portion of the vibrating body by vibrating the vibrating body, and transmits the motion to the driven body to be a driving force for driving the driven body. . FIG. 1 is a plan view showing an embodiment of a vibrating body holding mechanism 1 according to the present invention. The vibrating body holding mechanism 1 shown in FIG. 1 is an example in which the ultrasonic motor 10 including the vibrating body holding mechanism 1 according to the present invention is applied to a focus lens driving device 90 for moving an imaging focus lens of an imaging device. It is. The focus lens driving device 90 is a drive source that moves the focus lens for optical focusing in the optical axis direction, and the ultrasonic motor 10 is disposed on the outer periphery of the focus lens. In the following description, the description will be made mainly using the form shown in FIG.

[Vibrating body holding mechanism]
First, the structure of the vibrating body holding mechanism 1 according to the present invention will be described. The vibrating body holding mechanism 1 holds the vibrating body 2 of the ultrasonic motor 10 and includes the vibrating body 2 and a holding member 3 that houses and holds the vibrating body 2 so as to vibrate therein.

Vibrating body: In the vibrating body holding mechanism 1 according to the present invention, the vibrating body 2 is provided in the rectangular columnar body portion 21 accommodated in the holding member 3 and the body portion 21, and protrudes outside the holding member 3. And a vibrating body output unit 22 provided. FIG. 2 is a plan view showing an example of the shape when the vibrating body 2 is viewed from the upper surface side. The vibrating body 2 uses a plurality of piezoelectric elements 20 connected to electrodes (not shown). As shown in FIG. 2, in the ultrasonic motor 10 of the present embodiment, the body portion 21 has a substantially rectangular flat plate shape as the vibrating body 2, and a protruding vibration output is provided on one end 21 a side of the body portion 21. The unit 22 is provided.

  When a predetermined alternating voltage is applied to each electrode connected to the piezoelectric element 20, the body portion 21 is caused to expand and contract in the direction of arrow A in FIG. 2 (primary longitudinal vibration), and in the direction of arrow B. Bending vibration occurs. Then, by aligning the frequency of each electrode and changing the phase by a predetermined amount, the primary longitudinal vibration and the bending vibration are combined, and the vibration output unit 22 generates a desired motion such as an elliptical motion or a horizontal reciprocating motion. be able to. The ultrasonic motor 10 according to the present embodiment generates an elliptical motion at a point P of the vibration output unit 22 of the vibrating body 2.

  Specifically, the point P of the vibration output unit 22 of the vibrating body 2 is set as the center point of the motion generated in the output unit 22, passes through the center point P of the output unit 22, and is output to the driven body 6. When the reference line L is a line perpendicular to the contact surface with which the part 22 comes into contact, the longitudinal vibration and bending vibration of the body part 21 are combined on the reference line L, and the elliptical motion of the output part 22 is synthesized. It is converted into.

  The vibrating body 2 is arranged such that a vibrating body output portion 22 provided on the one end 21a side of the body portion 21 contacts the driven body 6, and the other end 21b side surface of the body portion 21 is placed on the other end. The pressurizing mechanism 7 which is an urging means for pressing the surface on the 21b side against the one end 21a side is arranged to contact. The driven body 6 and the pressurizing mechanism 7 will be described in detail later.

Holding member: The holding member 3 of the vibrating body holding mechanism 1 according to the present invention is configured by wall surfaces arranged in parallel at predetermined intervals along four side surfaces constituting the body portion 21 of the vibrating body 2. It is characterized in that a vibration body accommodating portion and resonance preventing means for suppressing the vibration generated by the vibrating body 2 from being transmitted to the wall surface are provided inside the wall surface constituting the vibration body accommodating portion.

  FIG. 3 is a view of the cross section taken along the line AA of the vibrating body holding mechanism 1 in FIG. The vibrating body housing portion 31 of the holding member 3 is configured by a rectangular cylindrical frame body having both ends opened, and a space for housing the body portion 21 of the vibrating body 2 is formed therein. With this configuration, the vibrating body 2 is housed in the vibrating body housing portion 31 with the surface on the one end 21a side and the surface on the other end 21b side of the body portion 21 exposed. In the present embodiment shown in FIGS. 1 and 3, the surface of the body 21 of the vibrating body 2 on the side of the one end 21 a where the vibration output portion 22 is provided and its periphery, and the other end 21 b on the opposite side of the vibration output portion 22. The other surface is exposed, and the other surface is substantially covered with the wall surface that constitutes the vibrating body accommodating portion 31.

  The four wall surfaces (that is, the upper wall surface 32, the lower wall surface 33, and both side wall surfaces 36 and 37) constituting the vibrating body housing portion 31 are in a state in which the body portion 21 of the vibrating body 2 is housed inside the vibrating body 2. Along the four side surfaces (that is, the upper surface 21c, the lower surface 21d, and the both side surfaces 21e, 21f) constituting the body portion 21, they are arranged in parallel at a predetermined interval.

Resonance prevention means: The vibrating body holding mechanism 1 of the present invention has four side surfaces (21c, 21d, 21e, 21f) constituting the body portion 21 of the vibrating body 2 and a predetermined interval on the outer periphery of the side surfaces. Resonance prevention means is provided between the four wall surfaces (32, 33, 36, 37) that constitute the vibrator housing portion 31 provided. The resonance preventing means is for suppressing the vibration generated by the vibrating body 2 from being transmitted to the wall surface of the vibrating body accommodating portion 31. Based on this basic technical idea, there are the following resonance prevention means provided in the vibrator holding mechanism 1 according to the present invention. Hereinafter, the resonance prevention means provided in the vibrating body holding mechanism 1 according to the present invention is broadly classified as “first resonance prevention means”, “second resonance prevention means”, and “third resonance prevention means”.

"First resonance prevention means": The first resonance prevention means includes a concave portion provided on one inner wall surface of the pair of opposed inner wall surfaces in the wall surface constituting the vibrating body housing portion of the holding member 3, An elastic member is disposed in the recess, a recess is provided on the other inner wall surface, and a rolling element is disposed in the recess.

“Second Resonance Prevention Unit”: The second resonance prevention unit includes a concave portion formed on one inner wall surface of the pair of opposed inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member 3. The elastic member and the rolling element are disposed in the recess, the recess is provided on the other inner wall surface, and the rolling element is disposed in the recess.

“Third resonance preventing means”: Further, the third resonance preventing means includes a concave portion formed on one inner wall surface of the pair of opposed inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member 3. Provided, an elastic member and a rolling element are provided in the recess, a recess is provided on the other inner wall surface, and the elastic member and the rolling element are provided in the recess.

  Here, “elastic member” and “rolling element”, which are components common to the above-described resonance preventing means, will be described.

“Elastic Member”: First, the “elastic member” will be described. The elastic member is made of an elastic material such as rubber, a spring, or an elastic resin component, and is a member that applies a pressing force to the body portion 21 of the vibrating body 2. FIG. 4 is a schematic diagram for explaining the shape of the elastic member. As shown in FIG. 4A, the elastic member 4 has a tapered shape from the one end face 41 toward the other end face 42, and a center connecting the center point of the one end face 41 and the center point of the other end face 42. The cross-sectional shape including the line 4L is configured to be line symmetric with respect to the center line 4L. As the outer shape of the elastic member 4, for example, a truncated cone shape, a quadrangular pyramid shape, and the like can be considered. . Furthermore, in consideration of manufacturing cost, mounting stability, and the like, it is preferable to use a spring material as shown in FIG.

  In the elastic member 4, the one end surface 41 of the elastic member 4 is in surface contact with the bottom surface of the concave portion in the concave portion which is the accommodating portion of the elastic member 4 provided on the wall surface constituting the vibrating body accommodating portion 31 of the holding member 3. Arranged to do. For this reason, it is preferable that the one end surface 41 of the elastic member 4 has substantially the same shape as the bottom surface of the concave portion. Thus, by making the shape of the one end surface 41 of the elastic member 4 substantially the same as the shape of the bottom surface of the recess, positioning when attaching the elastic member 4 is facilitated, and after attaching the elastic member 4 Can prevent the displacement of the elastic member 4 from occurring.

  Further, the elastic member 4 has the center line 4L described above approximately 90 degrees with respect to the reference line L of the vibrating body 2 so that a pressing force can be applied vertically to the body portion 21 of the vibrating body 2. It is preferable to arrange in the position. Further, the elastic member 4 is preferably arranged at a position that becomes a node of the vibration so as not to hinder the vibration generated in the elastic body 2 that leads to the elliptical motion in the vibration output unit 22. Furthermore, when the rolling elements are arranged so as to contact the other end face 42 of the elastic member 4 as in the second resonance preventing means or the third resonance preventing means described later, the other end face 42 does not cause misalignment. It is preferable to set the area of the other end face 42 so that the rolling element and the rolling element are stably in contact with each other.

“Rolling body”: Next, the rolling element will be described. The rolling element is provided in order to suppress inconvenience that the vibration of the vibrating body 2 is transmitted to the wall surface of the vibrating body housing 31. That is, the vibrating body 2 has a disadvantage caused by the body portion 21 of the elastic member 4 being pressed by the pressing force of the elastic member 4 described above (specifically, the vibrating body 2 that leads to elliptical motion in the vibrating body output portion 22). This is provided to prevent the vibrations of the base member 9 and the like, the transmission of vibrations to surrounding members such as the base member 9 and the occurrence of resonance).

  The rolling element is provided so as to be able to roll in a recess that is a receiving part of the rolling element provided on a wall surface constituting the vibrating body accommodating part 31 of the holding member 3. As the rolling element, a rigid spherical body or a member such as a cylindrical body 50 as shown in FIG. 5 can be used, and it is particularly preferable to use a spherical body as shown in the present embodiment. . As described above, by using a spherical body as the rolling element, it is possible to efficiently convert the vibration body 2 into the elliptical motion of the vibration output unit 22 without inhibiting the above-described primary longitudinal vibration and bending vibration. .

  Here, each resonance preventing means described above will be described in detail with reference to the drawings. First, an embodiment of a vibrating body holding mechanism having first and second resonance preventing means will be described with reference to FIGS. 6 is a schematic diagram showing an arrangement when the vibrating body holding mechanism 1 of FIG. 1 is viewed from the side surface side, and FIG. 7 is a schematic diagram showing an arrangement when the vibrating body holding mechanism 1 is viewed from the upper surface side. is there. As shown in FIGS. 6 and 7, the vibrating body holding mechanism 1 of this embodiment includes a first resonance preventing means between the upper and lower wall surfaces 32 and 33 constituting the vibrating body housing portion 31 of the holding member 3. A second resonance preventing means is provided between the side wall surfaces 36 and 37.

  Regarding a specific configuration, first, the first resonance preventing means provided between the pair of opposing upper and lower wall surfaces 32 and 33 among the wall surfaces constituting the vibrating body accommodating portion 31 of the holding member 3 will be described. As shown in FIG. 6, in the holding member 3, two recesses 34 are provided on the inner surface of the upper wall surface 32 of the vibration body accommodating portion 31, and four recesses 35 are provided on the inner surface of the lower wall surface 33. These two concave portions 34 are cylindrical recesses formed on the upper wall surface 32 of the vibrating body housing portion 31 from the inner surface of the upper wall surface 32 facing the upper surface 21c of the vibrating body 2 toward the upper side. Both concave portions 34 are arranged so as to be arranged in a straight line parallel to the reference line L of the vibrator 2 described above.

  In addition, the recess 35 is formed in a rectangular tube shape, a substantially pyramid shape, or a substantially pyramid shape formed from the inner surface of the lower wall surface 33 facing the lower surface 21d of the vibrating body 2 toward the lower side on the lower wall surface 33 of the vibrating body housing 31. It is a conical depression. As shown in FIG. 7, the concave portion 35 has a center point C at a position that is symmetrical with respect to the concave portion 34 provided on the upper wall surface 32 and the reference line L of the vibrating body 2. One on each side of the center line 3L that is spaced apart at equal intervals, passes through the center point C, and has an angle of 90 degrees with respect to the reference line L. And the elastic member 4 is arrange | positioned at the recessed part 34 of the upper wall surface 32 mentioned above, and the rolling element 5 is arrange | positioned at the recessed part 35 of the lower wall surface 33, respectively.

  The elastic member 4 is arranged such that one end surface 41 abuts on the bottom surface (upper surface) of the recess 34 and the other end surface 42 abuts on the upper surface 21 c of the body portion 21 of the vibrating body 2. In addition, the rolling element 5 is disposed in the recess 35 so that the upper end portion thereof is in point contact with the lower surface 21 d of the body portion 21 of the vibrating body 2. Accordingly, the vertical direction of the body portion 21 of the vibrating body 2 is held by contact between the other end surface 42 of the elastic member 4 and only the contact point of the rolling element 5. That is, the vibrating body 2 is pressed from above by the elastic member 4, and the pressing force is received by the rolling element 5 provided on the lower surface 21d on the receiving surface side.

  In this case, when the vibrating body 2 performs a desired vibration that leads to the elliptical motion of the vibration output unit 22, the rolling element 5 rolls in the recess 35 in accordance with the vibration, so that the movement of the vibrating body 2 is caused by the elastic member 4. It becomes difficult to be disturbed by the pressing force. Thereby, the vibration body 2 can efficiently change the vibration to the elliptical motion of the vibration output unit 22 without suppressing the desired vibration of the vibration body 2 by the rolling of the rolling element 5. Further, the rolling element 5 makes it difficult for the vibration of the vibrating element 2 to be transmitted to the holding member 3. Thereby, the vibration of the vibrating body 2 is amplified and transmitted to surrounding members such as the holding member 3 and the base member 9, and the problem that these resonate can be prevented.

  Next, a description will be given of the second resonance preventing means provided between the pair of opposed side walls 36 and 37 among the wall surfaces constituting the vibrating body accommodating portion 31 of the holding member 3. As shown in FIG. 7, two concave portions 38 are provided on the inner surface of one side wall surface 36 of the vibration body accommodating portion 31, and two concave portions 39 are provided on the inner surface of the other side wall surface 37. The two concave portions 38 provided on the one side wall surface 36 are formed on the one side wall surface 36 of the vibration body accommodating portion 31 from the inner surface of the side wall surface 36 facing the side surface 21e of the vibration body 2 toward the outer surface side. It is a hollow formed. Both concave portions 38 are arranged so as to be arranged in a straight line parallel to the reference line L of the vibrator 2 described above.

  Further, the two concave portions 39 formed on the other side wall surface 37 are formed in the direction from the inner surface of the side wall surface 37 facing the side surface 21 f of the vibrating body 2 to the outer surface side in the side wall surface 37 of the vibrating body housing portion 31. It is a dent formed towards. Both concave portions 39 are arranged so as to be linearly arranged in parallel with the reference line L of the vibrator 2 described above, similarly to the concave portion 38 described above. Further, the both concave portions 39 are provided at positions that are line symmetric with respect to the concave portion 38 and the reference line L of the vibrating body 2. The elastic member 4 and the rolling element 5 are disposed in the recess 38 of the one side wall surface 36, and the rolling element 5 is disposed in the recess 39 of the other side wall surface 37.

  The one end surface 41 of the elastic member 4 is in contact with the bottom surface of the recess 38 and the other end surface 42 is in contact with the rolling element 5, which is opposite to the surface of the rolling element 5 that contacts the other end surface 42 of the elastic member 4. The side surface is arranged so as to make point contact with the side surface 21 e of the vibrating body 2. Further, the rolling elements 5 arranged in the recesses 39 are arranged so that the side surfaces thereof are in point contact with the side surfaces 21 f of the body part 21 of the vibrating body 2 in the state of being arranged in the recesses 39. Thereby, the side surface direction of the trunk | drum 21 of the vibrating body 2 is hold | maintained only by the point contact with the rolling element 5. FIG. That is, the lateral direction of the vibrating body 2 is received by the rolling element 5 provided on the other side surface 21f that receives the pressing force of the elastic member 4 through the rolling element 5 from the one side surface 21e. It becomes.

  In this case, when the vibrating body 2 performs a desired vibration that leads to an elliptical motion in the vibration output unit 22, the rolling element 5 that makes point contact with both side surfaces 21 e and 21 f rolls within the recesses 38 and 39 according to the vibration. For this reason, the movement of the vibrating body 2 is not easily inhibited by the pressing force (pressurization) of the elastic member 4. Thereby, the vibrating body 2 can be changed to the elliptical motion of the vibration output unit 22 without being hindered by a desired vibration by the rotation of the rolling element 5. Further, the motion of the vibrating body 2 is hardly transmitted to the holding member 3 by the rolling element 5. Thereby, the vibration of the vibrating body 2 is amplified and transmitted to surrounding members such as the holding member 3 and the base member 9, and the problem that these resonate can be prevented.

  As described above, in the vibrating body holding mechanism 1 shown in this embodiment, the vertical direction of the vibrating body 2 is held by the first resonance preventing unit, and the side surface direction is held by the second resonance preventing unit. Accordingly, it is possible to appropriately hold the vibrating body 2 and to generate a stable vibration in the vibrating body 2 while preventing the occurrence of resonance due to the vibration of the vibrating body 2. For this reason, it becomes possible to prevent the problem which has a bad influence on the drive of the ultrasonic motor 10, etc.

  In addition, the arrangement | positioning and shape of the resonance prevention means and each recessed part in this Embodiment mentioned above are an example of this invention to the last, Comprising: It is not restrict | limited to the said embodiment. For example, in the present embodiment, the first resonance prevention means is provided in the vertical direction of the vibrating body 2 and the second resonance prevention means is provided in the side surface direction. However, the second resonance prevention means is provided in the vertical direction. It may be provided, or the first resonance preventing means may be provided in the side surface direction. In place of these, it is also effective to provide a third resonance preventing means described in detail below.

  Next, the third resonance preventing means will be described with reference to the schematic view of the vibrating body holding mechanism 1 shown in FIG. As shown in FIG. 8, the third resonance preventing means is provided with two concave portions 38 on the inner surface of one side wall surface 36 of the vibrator accommodating portion 31 and two concave portions on the inner surface of the other side wall surface 37. 40 is provided. The two concave portions 38 provided on the one side wall surface 36 are formed on the one side wall surface 36 of the vibration body accommodating portion 31 from the inner surface of the side wall surface 36 facing the side surface 21e of the vibration body 2 toward the outer surface side. It is a hollow formed. Both concave portions 38 are arranged so as to be arranged in a straight line parallel to the reference line L of the vibrator 2 described above.

  Further, the two concave portions 40 formed on the other side wall surface 37 are formed in the direction from the inner surface of the side wall surface 37 facing the side surface 21 f of the vibrating body 2 to the outer surface side in the side wall surface 37 of the vibrating body housing portion 31. It is a dent formed towards. Both concave portions 40 are arranged so as to be arranged in a straight line parallel to the reference line L of the vibrating body 2 described above, similarly to the concave portion 38 described above. Further, the both concave portions 40 are provided at positions that are line symmetric with respect to the concave portion 38 and the reference line L of the vibrating body 2. The elastic member 4 and the rolling element 5 are disposed in the concave portion 38 of the one side wall surface 36, and the elastic member 4 and the rolling element 5 are disposed in the concave portion 40 of the other side wall surface 37 in the same manner as the concave portion 38. Is done.

  The one end surface 41 of the elastic member 4 is in contact with the bottom surface of the recess 38 and the other end surface 42 is in contact with the rolling element 5, opposite to the surface of the rolling element 5 on the side contacting the other end surface 42 of the elastic member 4. It arrange | positions so that the surface of a side may contact in the side surface 21e of the vibrating body 2. FIG. Further, the elastic member 4 and the rolling element 5 disposed in the recess 40 are in contact with the bottom surface of the recess 40 at one end surface 41 of the elastic member 4 and the other end surface 42 are in contact with the rolling element 5. The surface opposite to the side contacting the other end surface 42 of the elastic member 4 is disposed so as to make point contact with the side surface 21 f of the vibrating body 2. Thereby, the side surface direction of the trunk | drum 21 of the vibrating body 2 of this embodiment is hold | maintained only by the point contact with the rolling element 5. FIG. That is, the side surfaces 21e and 21f receive the pressing force of the elastic member 4 from both sides via the rolling elements 5, and the pressing force from the opposite side by the rolling elements 5 on both sides.

  In this case, when the vibrating body 2 vibrates in a desired manner, the rolling element 5 that makes point contact with both side surfaces 21e and 21f rolls within the recesses 38 and 40 in accordance with the vibration. It becomes difficult to be disturbed by the pressing force of the elastic member 4 pressed from above. Thereby, the vibrating body 2 can be changed to the movement of the vibration output unit 22 without being hindered by the desired vibration by the rotation of the rolling element 5. Further, the rolling element 5 makes it difficult for the vibration of the vibrating element 2 to be transmitted to the holding member 3. Thereby, the vibration of the vibrating body 2 is amplified and transmitted to surrounding members such as the holding member 3 and the base member 9, and the problem that these resonate can be prevented.

[Ultrasonic motor]
Next, the structure of the ultrasonic motor 10 provided with the vibrating body holding mechanism 1 described above will be described. The ultrasonic motor 10 includes a quadrangular columnar vibrating body 2, a driven body 6, a pressurizing mechanism 7, and a pressurizing source 8. In addition, since the structure of the vibrating body 2 is as above-mentioned, detailed description is abbreviate | omitted here and the other structural member shall be demonstrated below.

  The driven body 6 is rotationally driven by the elliptical motion of the vibration output unit 22 of the vibrating body 2. The driven body 6 of the present embodiment shown in FIG. 1 has a rotor 61, a shaft 62, and a driving force output unit 63.

  The rotor 61 has a substantially columnar outer shape, and is arranged so that the vibration output portion 22 of the vibrating body 2 is in pressure contact with the outer peripheral surface of the rotor 61. The rotor 61 is attached to the base member 9 so as to be rotatable about a shaft 62. Similarly to the rotor 61, the driving force output unit 63 is also provided to be rotatable around the shaft 62.

  With this configuration, when the rotor 61 rotates, the driving force output unit 63 rotates in synchronization with the rotation of the rotor 61. Specifically, when the vibration output unit 22 of the vibrating body 2 performs a desired motion, the rotor 61 is rotated by the frictional force between the vibration output unit 22 and the rotor 61. The driving force output unit 63 also rotates in synchronization with the rotation of the rotor 61. A focus lens drive mechanism (not shown) is connected to the drive force output unit 63 and acts as a drive source for the focus lens drive device 90. The driven body 6 may be a driving object itself that is directly driven by the ultrasonic motor 10, or may be an indirect member that transmits a driving force to the driving object.

  Next, the pressurizing mechanism 7 will be described. The pressurizing mechanism 7 is an urging means for bringing the vibrating body output unit 22 provided on the one end 21 a side of the vibrating body 2 into pressure contact with the rotor 61 of the driven body 6 described above. That is, in the ultrasonic motor 10 according to the present invention, the surface on the other end 21b side of the vibrating body 2 is placed on the one end 21a side in order to press the vibrating body output portion 22 of the vibrating body 2 to the rotor 61 of the driven body 6. An urging means for pressing is provided.

  As shown in FIG. 1, the pressurizing mechanism 7 of the present embodiment includes a pressurization source 8, a pressurization transmission member 71, and a pressurization correction unit 72. The pressurizing source 8 is formed of a spring coil and is disposed at a position separated from the vibrating body 2. The end 81 at one end of the spring coil is fixed to the base member 9, and the end 82 at the other end is connected to the pressurizing transmission member 71.

  The pressurizing transmission member 71 is a member for transmitting the pressurizing force of the pressurizing source 8 to the vibrating body 2. The pressurizing transmission member 71 of the present embodiment has an arm shape. The arm-shaped pressurizing transmission member 71 is attached to the base member 9 via the support shaft 15 and is provided to be rotatable about the support shaft 15. The pressurizing transmission member 71 is provided with a pressurizing source connecting portion 73 for connecting to the pressurizing source 8. Then, by connecting the pressurizing source connecting portion 73 and the pressurizing source 8, a force acts on the pressurizing source connecting portion 73 in the direction of the arrow D and rotates around the support shaft 15. As a result, a force acts in a direction in which the end of the pressurizing source connection portion 73 facing the vibrating body 2 approaches the vibrating body 2. As a result, a force that presses the vibrating body 2 toward the driven body 6 is generated in the pressurizing mechanism 7.

  Further, the pressurizing correction unit 72 described above corrects the angle of the pressing force of the pressurizing transmission member 71 with respect to the surface on the other end 21 b side of the vibrating body 2, and makes a predetermined angle with respect to the vibrating body 2. This is for applying pressure. The pressurizing correction unit 72 is made of engineering plastic and is rotatably provided at a contact position with the vibrating body 2. As shown in FIG. 1, the pressurizing correction unit 72 is disposed between the pressurizing transmission member 71 and the surface on the other end 21 b side of the vibrating body 2. Thereby, it is possible to apply pressure to the vibrating body 2 at a predetermined angle by correcting the angle of the pressing force of the pressurizing transmission member 71 to the surface on the other end 21 b side of the vibrating body 2. As a result, the vibrating body 2 can be stably pressed against the driven body 6 side at an appropriate angle.

  Thus, since the ultrasonic motor 10 according to the present invention includes the vibrating body holding mechanism 1 described above, it is possible to vibrate the vibrating body 2 in an appropriate state while preventing the occurrence of resonance caused by the vibration of the vibrating body 2. Therefore, there is no vibration unevenness and the driving efficiency can be improved. In addition, since the focus lens driving device 90 according to the present invention uses the ultrasonic motor 10 with high driving efficiency in this way, it is possible to achieve both reduction in power consumption and high-precision lens driving control. It is suitable as a drive source for the focus lens drive device. In the present embodiment, as described above, the ultrasonic motor including the vibrating body holding mechanism according to the present invention has been described as being applied to the drive source of the focus lens drive device. However, the present invention is not limited to application to such a focus lens driving device, and can also be applied to other driving devices. For example, it is also effective to use an ultrasonic motor provided with a vibrating body holding mechanism according to the present invention as a drive source of a zoom lens drive device that moves a zoom lens for optical zoom.

  The vibrating body holding mechanism according to the present invention prevents the vibration body of the ultrasonic motor from generating resonance due to vibration of the vibrating body, and suppresses unnecessary vibration that leads to a decrease in output efficiency and an output error, thereby reducing desired vibration. Can be appropriately held in a possible state. For this reason, the ultrasonic motor provided with the vibrating body holding mechanism has high drive efficiency and excellent drive control ability. Therefore, the present invention is also effective in a lens driving device that requires zooming and focusing agility, such as a camera for moving image shooting. In addition, since the drive efficiency is good, the use time can be improved when used in a lens drive device such as a battery-powered camera.

DESCRIPTION OF SYMBOLS 1 Vibrating body holding mechanism 2 Vibrating body 3 Holding member 4 Elastic member 5 Rolling body 6 Driven body 7 Pressurizing mechanism 8 Pressurizing source 9 Base member 10 Ultrasonic motor 15 Support shaft 20 Piezoelectric element 21 Body 21a One end 21b The other end 21c Upper surface 21d Lower surface 21e, 21f Side surface 22 Vibration output part 31 Vibrating body accommodating part 32 Upper wall surface 33 Lower wall surface 34, 35 Recess 36 One side wall surface 37 Other side wall surface 38, 39, 40 Recessed portion 41 One end surface 42 Other end surface 61 Rotor 62 Shaft 63 Driving force output section 71 Pressurizing transmission member 72 Pressurizing correction section 73 Pressurizing source connecting section 81 One end of spring coil 82 Other end of spring coil 90 Lens driving device L Reference line 3L Center line 4L Center line P The center point of the motion generated in the output section

Claims (7)

A vibrating body holding mechanism comprising a vibrating body and a holding member that houses and holds the vibrating body in a freely oscillating manner,
The vibration body includes a quadrangular columnar body portion accommodated in the holding member, and a vibration output portion provided on one end side of the body portion and protruding outside the holding member,
The holding member constitutes a vibrating body housing portion constituted by wall surfaces arranged in parallel at predetermined intervals along four side surfaces constituting the body portion of the vibrating body, and the vibrating body housing portion. A vibrating body holding mechanism comprising a resonance preventing means for suppressing vibration generated by the vibrating body from being transmitted to the wall surface on the inner surface of the wall surface.   The resonance prevention means includes a concave portion provided on one inner wall surface of the pair of opposing inner wall surfaces, and an elastic member disposed in the concave portion, on the wall surface constituting the vibrating body housing portion of the holding member. The vibrating body holding mechanism according to claim 1, wherein a concave portion is provided on the inner wall surface of the, and a rolling element is disposed in the concave portion.   The resonance preventing means includes a concave portion provided on one inner wall surface of the pair of opposing inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member, and the elastic member and the rolling element are disposed in the concave portion. The vibrating body holding mechanism according to claim 1, wherein a recess is provided on the other inner wall surface, and a rolling element is disposed in the recess.   The resonance preventing means includes a concave portion provided on one inner wall surface of the pair of opposing inner wall surfaces on the wall surface constituting the vibrating body housing portion of the holding member, and the elastic member and the rolling element are disposed in the concave portion. The vibrating body holding mechanism according to claim 1, wherein a recess is provided on the other inner wall surface, and an elastic member and a rolling element are disposed in the recess.   The vibrating body holding mechanism according to claim 1, wherein a conical spring material is used as the elastic member.   The vibrating body holding mechanism according to any one of claims 1 to 5, and the prismatic vibrating body is configured to press the vibration output portion provided on the one end side against the driven body. An ultrasonic motor comprising urging means for pressing a surface on the other end side against the one end side. A lens driving device for an imaging device,
A lens driving device using the ultrasonic motor according to claim 6.

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