JP2016101023A - Vibration wave motor and optical device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact thin vibration wave motor capable of applying pressure to a transducer even when posture of the transducer is tilted.SOLUTION: A vibration wave motor includes: a vibrator having a projection; a slide member having a friction contact surface with which the projection is frictionally in contact; a vibrator holding member for holding the vibrator; and a pressure applying part for pressing the vibrator to the slide member. By making the vibrator to generate vibrations, the vibrator and the slide member are relatively moved. The pressure applying part is mounted to the vibrator holding member so as to be capable of rotating around an axis line in a direction perpendicular to a direction in which the vibrator and the slide member are relatively moved and to a pressure applying direction by the pressure applying part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibration wave motor, and more particularly to an ultrasonic motor in which a vibrator and a sliding member that is in frictional contact with the vibrator are relatively moved by ultrasonic vibration generated in the vibrator.

  In recent years, in an imaging apparatus such as a digital camera or a video camera, an ultrasonic motor as a vibration wave motor superior to an electromagnetic motor is used as a driving source for focusing and zooming.

  An ultrasonic motor is a motor that obtains a driving force by a frictional force generated between the two by exciting ultrasonic vibration in a vibrator having a piezoelectric element and pressurizing and contacting the vibrator with a sliding member. . As described above, since an ultrasonic motor obtains a driving force based on a frictional force, it is important to obtain a stable frictional force under stable pressure. However, in order to perform stable pressurization, a complicated pressurization mechanism and a space for it are required, and there is a problem that the ultrasonic motor becomes large. On the other hand, an example of an ultrasonic motor for realizing stable pressurization with a small mechanism has been proposed.

  For example, in Patent Document 1, the pressure spring is a leaf spring, both ends thereof are held by a case member, and the size is reduced by using a configuration in which the center protrusion of the leaf spring is pressed by the center portion of the leaf spring. ing. In Patent Document 2, a support shaft is provided on both end faces of a vibrator at a position corresponding to a node of a standing wave of the vibrator, and a compact structure is configured using a configuration in which a pressure plate biased by a coil spring presses the support shaft. Has been realized. In both Patent Document 1 and Patent Document 2, stable pressurization is realized by performing pressurization toward the center of the vibrator.

JP 2009-268236 A JP-A-9-215350

  In the conventional ultrasonic motor disclosed in Patent Document 1 and Patent Document 2 described above, when the posture of the vibrator is inclined due to some factor such as a manufacturing error, the direction of pressurization is at the center position of the vibrator. It will deviate from the direction it heads, making it impossible to obtain a stable friction force.

  Accordingly, an object of the present invention is to provide a vibration wave motor having a compact configuration that can stably pressurize a vibrator even when the posture of the vibrator is inclined.

  In order to achieve the above object, in the present invention, a vibrator having a protrusion, a sliding member having a friction contact surface with which the protrusion comes into frictional contact, a vibrator holding member that holds the vibrator, and a vibrator are provided. A vibration wave motor that includes a pressurizing unit that pressurizes the sliding member and causes the vibrator and the sliding member to move relative to each other by generating vibration in the vibrator; and a direction in which the vibrator and the sliding member move relative to each other The pressurizing unit is attached to the vibrator holding member so as to be rotatable around an axis in a direction orthogonal to the pressurizing direction by the pressurizing unit.

  According to the present invention, it is possible to obtain a vibration wave motor having a compact configuration that can stably pressurize a vibrator even when the posture of the vibrator is inclined.

It is sectional drawing of the drive direction which shows the structure of the ultrasonic motor in Example 1 of this invention. It is sectional drawing of the direction orthogonal to the drive direction which shows the structure of the ultrasonic motor in Example 1 of this invention, and is sectional drawing in the AA arrow of FIG. It is a perspective view of the pressurization part of the ultrasonic motor in Example 1 of the present invention. It is a perspective view of a vibrator holding member of an ultrasonic motor in Example 1 of the present invention. It is a perspective view which shows the state by which the vibrator | oscillator was attached to the vibrator holding member of the ultrasonic motor in Example 1 of this invention. It is side part sectional drawing which shows the structure of the lens barrel in which the ultrasonic motor in Example 1 of this invention was used. In the ultrasonic motor in Example 1 of this invention, it is sectional drawing which shows the state in which the vibrator | tilt inclined. It is sectional drawing of the drive direction which shows the structure of the ultrasonic motor in Example 2 of this invention. It is sectional drawing of the direction orthogonal to the drive direction which shows the structure of the ultrasonic motor in Example 2 of this invention, and is sectional drawing in the BB arrow of FIG. It is sectional drawing which shows the state which the vibrator | oscillator inclined by the manufacturing error of the vibrator | oscillator of the ultrasonic motor in Example 2 of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of each embodiment, the relative movement direction of the vibrator and the sliding member is defined as “X-axis” to facilitate understanding in relation to the drawings. In addition, the direction in which the vibrator is pressed against the sliding member by the pressurizing spring when there is no inclination due to some factor such as a vibrator manufacturing error of the ultrasonic motor is expressed as “Z axis”, X axis and Z axis. The direction orthogonal to the direction is defined as the “Y-axis” and will be described.

Example 1
Hereinafter, the configuration of the first embodiment of the ultrasonic motor as the vibration wave motor of the present invention will be described with reference to FIGS. 1 to 5.

  FIG. 1 shows a configuration of an ultrasonic motor according to a first embodiment of the present invention, and is a cross-sectional view (XZ cross section) in a relative movement direction between a vibrator and a sliding member. FIG. 2 shows a configuration of the ultrasonic motor according to the first embodiment of the present invention, and is a cross-sectional view (YZ cross section) in a direction orthogonal to the relative movement direction of the vibrator and the sliding member. FIG. 3 is a perspective view of the pressure unit of the ultrasonic motor according to the first embodiment of the present invention. FIG. 4 is a perspective view of the vibrator holding member of the ultrasonic motor according to the first embodiment of the present invention. FIG. 5 is a perspective view showing a state in which the vibrator is attached to the vibrator holding member of the ultrasonic motor according to the first embodiment of the present invention.

  1 and 2, reference numeral 8 denotes a unit base that supports the whole ultrasonic motor unit. On the unit base 8, the sliding member 3 is fixed on the lower side in the Z-axis direction, and the top plate 9 as a cover member is fixed on the upper side in the Z-axis direction. Four rolling members 6 are incorporated in the top plate 9. The rolling member 6 rolls in a state of being sandwiched by guide grooves provided in the top plate 9 and the vibrator holding member 5, so that the vibrator holding member 5 moves in the moving direction 6a (X-axis direction) in FIG. It is possible to move to.

  As shown in FIG. 4, the vibrator holding member 5 is provided with four guide grooves 5b, and the top plate 9 is also provided with the same four guide grooves at positions facing the guide grooves 5b (not shown). Rolling members 6 are sandwiched and incorporated in these guide grooves.

  As shown in FIG. 5, the vibrator holding member 5 includes a piezoelectric element 2 that is excited by being applied with a high-frequency driving voltage when the vibrator holding member 5 is driven, and a vibration plate in which ultrasonic vibration is excited by the piezoelectric element 2. 1 is attached. The vibrator 101 is attached to the vibrator holding member 5 with an adhesive or the like at the attachment portion of the vibrator holding member 5 provided at two locations in the X-axis direction. Note that the piezoelectric element 2 and the diaphragm 1 are bonded with an adhesive to constitute the vibrator 101. The diaphragm 1 has two protrusions 1a having a spherical tip arranged side by side in the X-axis direction, which is the driving direction.

  As shown in FIG. 3, a pressure member 11, which is a thin plate spring for biasing the vibrator 101 to the sliding member 3 by pressure, is attached to the two brackets 10. In the present embodiment, the two brackets 10 serving as support members and the pressure member 11 constitute a pressure unit.

  As shown in FIGS. 1 and 2, the pressure base 7 that receives the pressure applied from the pressure member 11 by a projection 7 a having a spherical surface is attached to the vibrator 101 and the diaphragm 1 of the piezoelectric element 2 is attached to the vibrator 101. It is fixed to the piezoelectric element 2 on the side opposite to the side where it is provided. The pressurization base 7 receives pressure from the pressurization member 11 disposed above the pressurization base 7, and the pressurization base 7 pressurizes the vibrator 101 against the sliding member 3. The part 1a is in frictional contact with the frictional contact surface 3a of the sliding member 3.

  As shown in FIG. 4, the vibrator holding member 5 is provided with a support shaft 5 a that rotatably holds a pressurizing unit including a pressurizing member 11 and a bracket 10. The support shaft 5a is a direction orthogonal to the direction 6a (X-axis direction) in which the vibrator 101 and the sliding member 3 move relative to each other and the pressurizing direction (Z-axis direction) by the pressurizing member 11, that is, the vibrator holding member. 5 in the Y-axis direction, which is a direction crossing 5. Here, the support shaft 5a is disposed so as to be positioned in the vicinity of the friction contact surface 3a where the two protrusions 1a of the vibrator 101 and the sliding member 3 are in contact with each other. Further, the support shaft 5 a is provided so as to protrude inward so as to face each other from both edges in a direction crossing the vibrator holding member 5.

  As shown in FIG. 3, a hole 10 a is formed in each of the two brackets 10. Respective support shafts 5a of the vibrator holding member 5 are attached to the respective hole portions 10a so as to be received. When the pressurizing unit composed of the pressurizing member 11 and the bracket 10 shown in FIG. 3 is incorporated into the vibrator holding member 5, they can be easily incorporated by elastically deforming the thin plate-like pressurizing member 11. Is possible. Note that the pressurizing portion including the bracket 10 and the pressurizing member 11 is rotatably held around the support shaft 5 a of the vibrator holding member 5. That is, as shown in FIG. 1 and FIG. 2, the pressurizing unit is divided into a direction in which the vibrator 101 and the sliding member 8 are relatively moved (X-axis direction) and a pressurizing direction by the pressurizing unit (Z-axis direction). It is attached to the vibrator holding member so as to be rotatable around an axis line 54 in the orthogonal direction (Y-axis direction). Preferably, the vibrator 101 can be stably pressed against the sliding member 3 so that the axis 54 is positioned on the friction contact surface 3a or in the vicinity thereof. Details will be described later.

  In addition, as shown in FIG. 2, the pressurizing unit including the pressurizing member 11 and the bracket 10 is disposed so as to straddle the vibrator 101 in the direction orthogonal to the moving direction (Y-axis direction). Thus, by arranging the bracket 10 of the pressurizing unit on both sides of the vibrator 101 so as to be attached to the vibrator holding member 5, it becomes possible to make the ultrasonic motor compact and thin, In addition, stable pressurization is realized with a compact configuration.

  In this embodiment, the support shaft 5a is provided in the vibrator holding member 5 and the hole 10a is provided in the bracket 10 of the pressurizing portion. However, the hole is provided in the vibrator holding member 5 and the support shaft is provided in the bracket 10. May be provided. That is, the vibrator holding member 5 may have one of the support shaft and the hole, and the pressurizing portion may have either the support shaft and the hole. Also, a configuration may be adopted in which holes are provided in both the support member that supports the pressure member and the vibrator holding member, and separate support shafts are inserted into these holes.

  The ultrasonic motor as the vibration wave motor of the present invention is configured as described above. As shown in FIGS. 1 and 2, the pressurizing member 11 applies pressure to the sliding member 3 in the arrow direction 11 a (Z-axis direction). That is, the applied pressure is applied toward the direction 11 a that coincides with the center line 52 of the vibrator 101 between the two protrusions 1 a of the diaphragm 1. Then, by generating ultrasonic vibration in the vibrator 101, a driving force is generated by friction between the protrusion 1a and the sliding member 3, and the vibrator 101 moves in the moving direction 6a (X-axis direction) with respect to the sliding member 3. ). In this embodiment, the vibrator 101 is moved and the sliding member 3 is fixed. However, the vibrator 101 may be fixed and the sliding member 3 may be moved.

  Next, referring to FIG. 6, the configuration of the lens barrel using the ultrasonic motor of the present invention as a driving source for focusing the lens barrel will be described.

  FIG. 6 is a side sectional view showing a configuration of a lens barrel using the ultrasonic motor according to the first embodiment of the present invention. In FIG. 6, the optical axis direction of the lens barrel that is an optical device coincides with the direction 6 a (X-axis direction) in which the vibrator 101 of the ultrasonic motor moves relative to the sliding member 3.

  The imaging optical system of the lens barrel 21 has a first group lens 22 and a second group lens 23 from the subject side. These lenses are held by the first-second lens barrel 27. Next, the focus lens 24 is disposed, and the focus lens 24 is held by the lens moving frame 28. Next, a fourth group lens 25 and a fifth group lens 26 are arranged, and these are held by a 4-5 group lens barrel 29. The first group lens 22, the second group lens 23, the fourth group lens 25, and the fifth group lens 26 are fixed lenses. A diaphragm unit 33 whose diaphragm is driven by the diaphragm unit drive motor 32 is provided between the second group lens 23 and the focus lens 24.

  The two main guide bars 30 for guiding the lens moving frame 28 in the direction of the optical axis 41 and moving back and forth are attached so as to extend in parallel to the optical axis 41 on the inner wall of the lens barrel 21. It has been. A unit base 8 is attached inside the lens barrel 21 so that the vibrator holding member 5 can move in the direction of the optical axis 41. The vibrator holding member 5 and the lens moving frame 28 are connected by a connecting member 31, and the focus lens 24 can be moved in the direction of the optical axis 41 by transmitting the driving force of the vibrator 101 to the lens moving frame 28. It becomes possible.

  Next, a case where the posture of the vibrator is inclined due to some factor such as a manufacturing error of the vibrator will be described with reference to FIG.

  FIG. 7 is a cross-sectional view showing a state where the vibrator is tilted due to a manufacturing error of the vibrator and other factors in the ultrasonic motor according to the first embodiment of the present invention. 7 is a view seen in the same direction as that of FIG.

  As shown in FIG. 7, when the dimension Y in the Z-axis direction of the right protrusion 1c is smaller than the dimension X in the Z-axis direction of the left protrusion 1b due to a manufacturing error of the diaphragm 1 or some other factor, the vibrator 101 Tilts in the direction indicated by arrow 51. Although the vibrator 101 is fixed to the vibrator mounting portion of the vibrator holding member 5, the vibrator 101 is inclined because the rigidity of the mounting portion is not so high. The pressurizing base 7 to which a pressing force is applied from the pressurizing member 11 is also tilted in accordance with the tilt of the vibrator 101. Since the bracket 10 of the pressurizing portion is rotatably attached to the support shaft 5a of the vibrator holding member 5 in the hole portion 10a, the pressurizing member that urges the pressurizing base 7 closely. 11 is also inclined according to the vibrator 101 and the pressure base 7. Therefore, when the vibrator 101 is inclined from the center line 52 to the center line 53, the applied pressure from the pressing member 11 is also applied to the vibrator 101 along the center line 53 inclined from the center line 52. At this time, since the pressing member 11 is configured to be urged by point contact to the protruding portion 7 a having a spherical curved surface of the pressing base 7, the vibrator 101 is preferably connected through the pressing base 7 in a well-balanced manner. A pressurizing force will be given to.

  Further, the pressing force from the pressurizing member 11 is preferably applied in the direction of the arrow 11 a that coincides with the center line 52 of the vibrator 101 between the two protrusions 1 a of the diaphragm 1. Further, the pressurizing part is suitably attached to the vibrator holding member 5 so that the axis 54 centered on the pressurizing part is located on the friction contact surface 3a of the friction member 3 or in the vicinity thereof. Thereby, even when the vibrator 101 is inclined, the pressure from the pressure member 11 is applied to the two protrusions 1a in a well-balanced manner toward the center between the two protrusions 1a of the vibrator 101. The Rukoto. Therefore, the vibrator 101 can be stably pressurized.

(Example 2)
Next, the vibration wave motor of the present invention capable of stably pressing the vibrator 101 against the sliding member 3 while reducing the thickness of the ultrasonic motor with reference to FIGS. 8 to 10. The configuration of the ultrasonic motor according to the second embodiment will be described. The basic configuration is the same as that of the first embodiment, and only the differences will be described here.

  FIG. 8 shows the configuration of the ultrasonic motor according to the second embodiment of the present invention, and is a cross-sectional view (XZ cross section) in the relative movement direction of the vibrator and the sliding member. FIG. 9 shows a configuration of the ultrasonic motor according to the second embodiment of the present invention, and is a cross-sectional view (YZ cross section) in a direction orthogonal to the relative movement direction of the vibrator and the sliding member. FIG. 10 is a cross-sectional view of the ultrasonic motor according to the second embodiment of the present invention viewed in the same direction as FIG. 8 and shows a state in which the vibrator is inclined due to a manufacturing error or some other factor.

  In order to guide the vibrator holding member 5 in the moving direction 6a (X-axis direction), the guide member of the rolling member 6 is provided on the sliding member 3 in the ultrasonic motor of this embodiment. Guide grooves 3b each having a V-shaped cross section are provided in the relative movement direction (X-axis direction) on each side surface on both sides of the friction contact surface of the sliding member 3 in the direction orthogonal to the relative movement direction (Y-axis direction). It is formed to extend. The vibrator holding member 5 is preferably formed with two guide grooves 5b each having a V-shaped cross section so as to face the guide groove 3b provided on the side surface of the sliding member 3. . A rolling member 6 is sandwiched between a guide groove 3 b provided on the side surface of the sliding member 3 and a guide groove 5 b provided on the vibrator holding member 5.

  In contrast to the configuration of the first embodiment in which the rolling member 6 is sandwiched between the top plate 9 and the vibrator holding member 5 to guide the vibrator holding member 5 in the relative movement direction, the second embodiment is configured as described above. Therefore, the unit base 8 and the top plate 9 can be omitted. This realizes a compact configuration in which the ultrasonic motor is further thinned. Other configurations are the same as those in the first embodiment.

  As shown in FIG. 10, even when the vibrator 101 is tilted in the direction indicated by the arrow 51 due to a manufacturing error or some other factor, the posture is changed as described in the first embodiment. Can be provided in a well-balanced manner. That is, also in the thin ultrasonic motor according to the second embodiment, the pressing force in the direction 11 a of the arrow by the pressing member 11 is the position of the center of the two protrusions 1 a along the center line 53 of the tilted vibrator 101. Given in the direction. Thereby, a pressurizing force can be given to two projection parts 1a with good balance.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Diaphragm 101 Vibrator 1a Protrusion part 1b Left side protrusion part 1c Right side protrusion part 2 Piezoelectric element 3 Sliding member 3a Friction contact surface 3b Guide groove 5 Vibrator holding member 5a Bearing shaft 5b Guide groove 6 Rolling member 6a Moving direction 7 Pressure base 7a Protrusion 8 Unit base 9 Top plate 10 Bracket 10a Hole 11 Pressure member 11a Arrow 21 Lens barrel 22 1st group lens 23 2nd group lens 24 Focus lens 25 4th group lens 26 5th group lens 27 1-2 Group lens barrel 28 Lens moving frame 29 4-5 group lens barrel 30 Main guide bar 31 Connecting member 32 Aperture unit drive motor 33 Aperture unit 41 Optical axis 51 Arrow 52 Center line 53 Center line 54 Axis line

Claims (10)

A vibrator having a protrusion, and
A sliding member having a frictional contact surface with which the protrusion is in frictional contact;
A vibrator holding member for holding the vibrator;
A pressurizing unit that pressurizes the vibrator against the sliding member;
In a vibration wave motor in which the vibrator and the sliding member move relative to each other by generating vibration in the vibrator,
The pressurizing part is attached to the vibrator holding member so that the vibrator and the sliding member can rotate about an axis perpendicular to the direction in which the vibrator and the sliding member move relative to each other and the pressurizing direction by the pressurizing part. A vibration wave motor characterized by the above.   The axis in a direction orthogonal to the direction in which the vibrator and the sliding member move relative to each other and the pressing direction by the pressing unit is located in the vicinity of the friction contact surface of the sliding member. The vibration wave motor according to claim 1.   The vibration wave motor according to claim 1, wherein the pressurizing unit is attached to the vibrator holding member so as to straddle the vibrator.   The vibrator holding member has either one of a support shaft or a hole, the pressure part has the other of the support shaft or the hole, and the support shaft is received in the hole. 4. The vibration wave motor according to claim 1, wherein the pressurizing unit is attached to the vibrator holding member. 5.   The pressurizing unit includes a pressurizing member that pressurizes the vibrator and a support member that attaches the pressurizing member to the vibrator holding member, and the pressurizing member includes a leaf spring. The vibration wave motor according to any one of claims 1 to 4.   6. A protrusion having a curved surface is provided between the leaf spring and the vibrator, and the leaf spring pressurizes the vibrator so as to pressurize the curved surface of the protrusion. The described vibration wave motor.   The vibrator has two protrusions, and the axis in the direction orthogonal to the direction in which the vibrator and the sliding member move relative to each other and the pressurizing direction by the pressurizing part is the two axes of the vibrator. 7. The device according to claim 1, wherein the pressure force is applied to the vibrator by the pressurizing unit toward the two projections of the vibrator. The vibration wave motor according to any one of the above.   The sliding member has side surfaces parallel to the relative movement direction on both sides of the friction contact surface, and a groove extending in the relative movement direction is provided on the side surface, and the vibrator holding member is A groove is formed opposite to the groove on the side surface of the sliding member, and the rolling member is sandwiched between the groove on the side surface of the sliding member and the groove of the vibrator holding member. The vibration wave motor according to claim 1, wherein the vibration wave motor is characterized in that:   The vibration wave motor according to any one of claims 1 to 8, wherein the vibration wave motor is an ultrasonic motor in which the vibrator generates ultrasonic vibration. The vibration wave motor according to any one of claims 1 to 9,
A lens moving frame that holds the lens and is coupled to the vibrator holding member of the vibration wave motor;
A guide bar that extends in the optical axis direction of the lens and guides the lens moving frame so as to be movable in the optical axis direction;
With
The optical apparatus, wherein the lens moving frame is moved in the optical axis direction along the guide bar by the driving force of the vibration wave motor.

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