JP6415195B2 - Drive device - Google Patents

Description

  The present invention relates to a driving device such as an ultrasonic motor that generates a driving force by generating ultrasonic vibration in a vibrator.

  Conventionally, there is no operation sound, driving from low speed to high speed is possible, and for example, an ultrasonic motor is used as a drive source for a camera or a lens, taking advantage of features such as high torque output. The ultrasonic motor disclosed in Patent Document 1 is held in a so-called pressure contact state in which the vibrator is biased by an elastic member with respect to the friction member. When ultrasonic vibration is excited in the vibrator under the pressure contact state, elliptical motion is generated in the contact portion in contact with the friction member of the vibrator, and the vibrator is driven straight. At this time, the vibrator is pressed or the pressing member has a line contact portion formed of a part of a cylinder, and freely moves around an axis orthogonal to the driving direction of the vibrator. The pressure can be applied perpendicular to.

JP 2013-66317 A Japanese Patent Laid-Open No. 2004-304877

  In the ultrasonic motor disclosed in Patent Document 1, the vibrator has a flat contact surface with the friction member, and if an error occurs due to assembly or processing of the component parts, the friction contact surface of the friction member and the vibrator As a result, the friction contact surface and the vibrator contact surface are in an unstable contact.

  In view of the above-described problems, the present invention provides an ultrasonic motor as a driving device that is driven by elliptical motion generated by ultrasonic vibration generated in a vibrator, and the vibrator contact surface and the friction member are stably and reliably provided with a simple configuration. It aims at making it contact.

In order to solve the above-described problems, a drive device according to the present invention includes a vibrator including a piezoelectric element and a diaphragm, a friction member having a friction contact surface in contact with the vibrator, and a holding member that holds the vibrator. When, the vibrator and a pressurizing means for pressurizing said friction member, wherein the voltage applied to the piezoelectric element and the friction member by the vibrating plate is vibrated with the vibrator move relative to the drive an apparatus, wherein the transducer, the frictional contact surfaces in contact, have a protrusion which have a curved shape about an axis parallel to the relative movement direction, said protrusions perpendicular to the friction contact surface It arrange | positions so that it may overlap with the said pressurization means in a direction .

  According to the present invention, in an ultrasonic motor as a driving device that drives a driven part by an elliptical motion caused by ultrasonic vibration generated in a vibrator, a configuration in which the vibrator and a friction member are stably brought into contact with each other is provided. Can do.

It is a disassembled perspective view of the ultrasonic motor in Example 1 of the present invention. It is an expansion perspective view which shows the joining state of the vibrator | oscillator and vibrator base of the ultrasonic motor in Example 1 of this invention. It is an expansion perspective view which shows the joining state of the diaphragm of the ultrasonic motor in Example 1 of this invention, and a piezoelectric element. It is sectional drawing of the ultrasonic motor in the direction where the vibrator | oscillator and friction member of the ultrasonic motor in Example 1 of this invention move relatively. It is sectional drawing of the ultrasonic motor in the direction orthogonal to the direction where the vibrator | oscillator and friction member of the ultrasonic motor in Example 1 of this invention move relatively. It is sectional drawing of the ultrasonic motor similar to the cross section of FIG. 5 in case the ultrasonic motor in Example 1 of this invention has an assembly error. It is an expanded sectional view of a vibrator and a friction member in a direction in which a vibrator and a friction member of an ultrasonic motor in Example 2 of the present invention move relatively. FIG. 6 is an enlarged detail view of the vibrator and the friction member viewed in a direction in which the vibrator and the friction member of the ultrasonic motor according to the second embodiment of the present invention move relative to each other.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by the following embodiment. In the description of each embodiment, in order to facilitate understanding in relation to the drawings, the relative movement direction of the vibrator and the friction member is “X axis”, and the vibrator is applied to the friction member by a pressurizing spring. The pressing direction to be pressed is defined as “Z axis”, and the direction orthogonal to the X axis and Z axis is defined as “Y axis”.

  FIG. 1 is an exploded perspective view of an ultrasonic motor 1 serving as a driving apparatus that is Embodiment 1 of the present invention. In addition, the same member is illustrated with the same symbol. Reference numeral 101 denotes a friction member having a friction contact surface 101a with which a vibrator 104, which will be described later, is in pressure contact. Reference numeral 102 denotes a diaphragm having a contact portion that comes into contact with the friction contact surface 101a of the friction member 101. Reference numeral 103 denotes a piezoelectric element that is pressure-bonded to the diaphragm 102 with an adhesive or the like. Then, by applying a voltage to the piezoelectric element 103 in a state where the piezoelectric element 103 is pressure-bonded to the diaphragm 102, ultrasonic vibration can be generated, and elliptical motion can be generated in the diaphragm 102. Note that the vibrator 104 includes a diaphragm 102 and a piezoelectric element 103. Reference numeral 105 denotes a vibrator base as a holding unit for holding the vibrator 104. Reference numeral 106 denotes a holding member that pressurizes and holds the vibrator 104 by a coil spring 108 via a pressing member 107. Note that the pressurizing means is not limited to the coil spring as long as the vibrator 104 can be pressurized. The coil spring 108 is in contact with a base member 109 that receives a pressure reaction force due to the elasticity of the spring. The base member 109 abuts on the rolling member 110 at the guide groove 109a, and guides the rolling member 110 along the guide groove 109a. The cover member 111 facing the base member 109 abuts on the rolling member 110 at a guide groove 111a provided on the cover member 111, and guides the rolling member 110 along the guide groove 111a. The cover member 111 is fixed to the fixing member 112 with screws 113. At the same time, the friction member 101 is also fixed to the fixing member 112.

  The base member 109 accommodates the transducer base 105 so as to contact the contact portion 105 a of the transducer base 105 in the relative movement direction with respect to the friction member 101. The vibrator 104 moves relative to the friction member 101 in the longitudinal direction (X-axis direction) of the friction member 101 by the elliptical motion generated by the ultrasonic vibration generated by the piezoelectric element 103. The vibrator base 105 to which the vibrator 104 is bonded and fixed, and the base member 109 that houses the vibrator base 105 move relative to the friction member 101 in the longitudinal direction of the friction member 101. The relative movement direction (X-axis direction) between the vibrator 104 and the friction member 101 described above is defined as the relative movement direction.

  Next, details of the constituent members of the ultrasonic motor 1 will be described. 2 and 3 are enlarged perspective views for explaining a joined state of the diaphragm 102 and the vibrator base 105 in FIG. FIG. 2 is a view as seen from the friction member 101 side. The diaphragm 102 and the vibrator base 105 are joined at the joint 102b by an adhesive, welding, or the like. In the figure, at the center of the diaphragm 102, two protrusions 102a having a substantially spherical shape are formed so as to be spaced apart in the relative movement direction. In this embodiment, there are two substantially spherical projections, but in order to hold the vibrator 104 without tilting in the relative movement direction, two or more projections having a substantially spherical shape arranged apart from each other. It is only necessary to provide a plurality of these.

On the other hand, FIG. 3 is a view seen from the side opposite to the friction member 101 side. A piezoelectric element 103 is pressure-bonded with an adhesive or the like on the back surface of the surface on which the protrusion 102a of the diaphragm 102 shown in FIG. 3 is formed. Note that the method of press-bonding the diaphragm 102 and the piezoelectric element 103 is not limited as long as the press-bonding is performed. The pressure conductive element 103 is obtained by integrally laminating a plurality of piezoelectric elements films. The piezoelectric element 103 is excited by applying a desired AC voltage, and two vibration modes are excited on the diaphragm 102 to which the piezoelectric element 103 is pressure-bonded. At this time, by setting the vibration phases of the two vibration modes to have a desired phase difference, an elliptical motion as indicated by an arrow in FIG. 2 occurs in the protrusion 102a. As shown in FIG. 2, this elliptical motion is generated by the vibrator 104 and transmitted to the friction contact surface 101 a of the friction member 101, so that the vibrator 104 can be moved relative to the friction member 101. Note that details regarding the laminated structure and vibration mode of the piezoelectric element described above are the same as the contents described in Patent Document 2, and therefore their description is omitted.

FIG. 4 is a cross-sectional view of the ultrasonic motor 1 cut along a cross section in the XZ plane including a straight line passing through the central part of two substantially spherical projections 102a spaced apart from each other in the diaphragm 102. FIG. Holding member 106 abuts against the piezoelectric element 103, the protrusion 102a of a substantially spherical shape of the diaphragm 102 is urged to the friction member 101 by the coil spring 108 in a direction perpendicular (Z-axis direction). The vibrator 104 receives a pressing force (biasing force) from the coil spring 108 by the holding member 106 via the pressing member 107, and can make pressure contact with the friction member 101 on the friction contact surface 101a. Yes. Then, as described above, the protrusion 102a is elliptically moved, so that the vibrator 104 is driven relative to the friction member 101 in the relative movement direction which is the left-right direction in FIG.

  On the other hand, the vibrator base 105 fixed to the vibration plate 102 is driven relative to the friction member 101 following the vibration plate 102. The vibrator base 105 abuts on the base member 109 at two contact portions 105 a and is accommodated in the base member 109. The base member 109 follows the vibrator base 105 and moves relative to the friction member 101. . Here, in this embodiment, the transducer base 105 and the base member 109 are configured to have a moderate clearance so as not to disturb the ultrasonic vibration of the transducer 104. It is not limited to the structure. For example, the vibrator base 105 may be abutted with the vibrator base 105 so as to be driven approximately in a pair. A configuration that cancels the hysteresis is also conceivable. On the other hand, the base member 109 receives a driving force from the vibrator base 105 in the relative movement direction and simultaneously receives a reaction force of the applied pressure from the coil spring 108.

  The pressure member 107 is supported by the base member 109 so as to be movable only in a direction substantially perpendicular to the friction contact surface 101a of the friction member 101. The pressure member 107 attaches the holding member 106 to the friction contact surface 101a perpendicularly. It is fast. Therefore, the holding member 106 can hold the vibrator in a displaceable manner in a direction parallel to the biasing direction of the coil spring 108. The holding member 106 is provided at the contact portion with the pressure member 107 so that the vibrator can be held so as to be rotationally displaceable with respect to the friction contact surface 101a around the Y axis parallel to the friction contact surface 101a and orthogonal to the relative movement direction. Part 106a. The pressurizing member 107 can be rotationally displaced about the Y axis orthogonal to the relative movement direction around the convex portion 106a by contacting the convex portion 106a of the holding member 106 with a flat contact portion 107a. The holding member 106 is supported by the support portion 109 b of the base member 109. By providing the support member 109b with a clearance with respect to the holding member 106 in the relative movement direction, the holding member 106 can be freely supported in the rotational displacement direction around the convex portion 106a. Accordingly, for example, the substantially spherical protrusion 102a of the diaphragm 102 can always be brought into contact with the friction contact surface 101a in a stable and stable manner according to the inclination of the relative movement direction of the friction member 101, for example.

  In addition, the convex part 106a of the holding member 106 may be configured in a cylindrical shape in which the central axis extends on the Y axis orthogonal to the relative movement direction. That is, the convex portion 106a of the holding member 106 has any shape such as a curved surface as long as the vibrator can be held so as to be rotationally displaceable with respect to the frictional contact surface 101a around the Y axis orthogonal to the relative movement direction. You can also have it.

  FIG. 5 is a cross-sectional view of the YZ plane orthogonal to the relative movement direction, and is a cross-sectional view taken along the central axis of the pressing member 107 in the vertical direction (Z-axis direction). Here, the protruding portion 102a is a protruding portion having an arc-shaped cross section formed so that the vibrator 104 can be rotationally displaced about the X axis parallel to the relative movement direction, and is in contact with the friction member 101 at a point.

  FIG. 6 shows a case where a shape error due to processing tolerance, for example, an error due to assembly in the bonding process occurs in the constituent members of each ultrasonic motor in the same cross section as FIG. In such a case, as shown in the present embodiment, the diaphragm 102 is provided with a substantially spherical protrusion 102a. As a result, a relative inclination is generated between the protrusion 102a and the friction contact surface 101a, and the contact of the protrusion is prevented from becoming unstable, and a stable contact state between the vibrator and the friction member can be obtained. it can.

The second embodiment shown in FIG. 7 is a modification of the first embodiment, and the diaphragm 102 is an example in which the shape of the protrusion 102a of the diaphragm 102 of the first embodiment is changed. The configuration other than the diaphragm 102 is the same as that of the first embodiment.

  FIG. 7 is a view showing a state in which the diaphragm 102 and the friction member 101 are in pressure contact with each other, and is an XZ sectional view in which a central portion of the diaphragm 102 is cut in the relative movement direction. Here, the diaphragm 102 is provided with a substantially cylindrical protrusion 102c and comes into contact with the friction contact surface 101a of the friction member 101 linearly in the relative movement direction.

  8 is also a cross-sectional view of the YZ plane perpendicular to the relative movement direction, showing a state where the diaphragm 102 and the friction member 101 of FIG. 7 are pressed.

  As described above, the protrusion 102a of the vibrator may be formed in a cylindrical shape having a central axis extending substantially parallel to the relative movement direction. That is, the protrusion 102a of the vibrator can have any shape such as a curved surface as long as it is configured to come into contact with the friction contact surface so as to be capable of rotational displacement with respect to the friction contact surface around an axis parallel to the relative movement direction.

  Since the diaphragm has the above-described configuration, a relative inclination similar to that shown in FIG. 6 can be generated between the substantially cylindrical projection 102c and the friction contact surface 101a, and the contact of the projection is unstable. Therefore, a stable contact state between the vibrator and the friction member can be obtained.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof. In the above embodiment, the linear drive type ultrasonic motor has been described in which the friction member has a frictional contact surface having a rectangular shape. However, the present invention is not limited to this, and for example, a rotary drive type ultrasonic motor having a frictional contact surface having an annular shape may be used.

DESCRIPTION OF SYMBOLS 1 Ultrasonic motor 101 Friction member 101a Friction contact surface 102 Diaphragm 102a Protrusion part 102b Joint part 102c Protrusion part 103 Piezoelectric element 104 Vibrator 105 Vibrator base 105a Contact part 106 Holding member 106a Protrusion part 107 Pressure member 108 Coil spring 109 Base member 109a Guide groove 110 Rolling member 111 Cover member 112 Fixing member 113 Screw

Claims (9)

A vibrator comprising a piezoelectric element and a diaphragm;
A friction member having a friction contact surface in contact with the vibrator;
A holding member for holding the vibrator;
Pressurizing means for pressurizing the vibrator to the friction member;
Wherein the the voltage applied to the piezoelectric element and the friction member by the vibrating plate is vibrated with the vibrator A driving device for the relative movement,
The vibrator before Symbol frictional contact surface in contact, have a protrusion which have a curved shape about an axis parallel to the relative movement direction,
The driving device according to claim 1, wherein the protrusion is disposed so as to overlap the pressurizing unit in a direction perpendicular to the friction contact surface . The driving apparatus according to claim 1, wherein the holding member is in contact with the piezoelectric element, and the vibrator is pressurized. Drive device according to claim 1 or 2 before Symbol projections, characterized in that it has a spherical shape. Before SL protrusions driving device according to claim 1 or 2, characterized in that it is constituted by a cylindrical shape having a central axis extending substantially parallel to the relative movement direction.   5. The driving device according to claim 1, wherein a plurality of the protrusions are provided on the vibrator so as to be separated from each other in the relative movement direction. 6.   The driving device according to claim 1, wherein the holding member holds the vibrator so as to be displaceable in a direction parallel to a pressing direction by the pressing unit. The pressing means includes a pressing member having a spring and a contact portion that pressurizes the holding member by an urging force of the spring, and the holding member, and the holding member is parallel to the friction contact surface and 7. The projection according to claim 1, wherein the vibrator has a convex portion that is pressed against the contact portion so as to be capable of rotational displacement with respect to the friction contact surface around an axis orthogonal to a relative movement direction. The drive device as described in any one.   The drive device according to claim 7, wherein the convex portion of the holding member has a curved surface shape.   9. The convex portion of the holding member is formed in a cylindrical shape having a central axis extending in a direction orthogonal to the relative movement direction and the pressurizing direction by the pressurizing unit. Drive device.

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