JP2007159211A - Driving device, vibration actuator, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving device, a vibration actuator, and electronic equipment wherein the plane of vibration of a vibrating body is excellent in accuracy. <P>SOLUTION: The driving device (10) is so constructed that: the vibrating body (11) has a flange (12d) in a plane different from the vibration plane (12a); an attaching member (40) has an attaching portion (42) to be attached to the flange (12d); and the attaching portion (42) has multiple recesses (43) in its portion opposite to the flange (12d). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive device, a vibration actuator, and an electronic device.

  As a vibration actuator, an ultrasonic motor that is a traveling wave motor using an ultrasonic vibration region is known. In general, an ultrasonic motor includes an elastic body that generates a progressive vibration wave on a vibration surface, a piezoelectric body having an upper surface attached to the elastic body, and a moving element that is driven by being pressed against the vibration surface of the elastic body. For example, it is used as a motor for driving a camera barrel.

Such an ultrasonic motor needs to be supported in a state where the flatness of the vibration surface is maintained in order to generate a favorable progressive vibration wave on the vibration surface.
As a technique related to the support structure of an ultrasonic motor, Patent Document 1 discloses an ultrasonic motor including a flange portion provided on a side surface of an elastic body and an attachment member attached to the flange portion and supporting the elastic body. .

  Since this type of ultrasonic motor generally pulls out the terminal electrode on the upper surface side of the piezoelectric body, it is necessary to form a conductive joint, such as solder, in the region from the lower surface side of the piezoelectric body to the elastic body. In some cases, it is difficult to strictly control the formation region of the conductive joint portion, and the conductive joint portion may reach the flange portion of the elastic body.

  In this case, when the attachment member is attached to the elastic body, the conductive joint formed on the flange portion is sandwiched between the attachment member and the elastic body, and the vibration surface of the elastic body is increased by the rise of the sandwiched conductive joint. Is deformed, and the flatness of the vibration surface is lost.

  In the state where the elastic body is attached to the mounting member, if the flatness of the elastic body is poor, the contact state between the vibration surface of the elastic body and the moving element is deteriorated, and abnormal noise is generated when the motor is driven, There is a risk that the drive torque is reduced. In order to avoid such performance deterioration, it is necessary to flatten the vibration surface by using means such as grinding and lapping.

  However, when the deformation of the vibration surface is large, there is a possibility that sufficient flatness cannot be obtained even if the sag amount of lapping is increased. Further, when the amount of sag increases, a thin plating film or the like formed on the vibration surface is scraped off, and there is a possibility that stable characteristics cannot be obtained when the motor is used.

  As a means for avoiding deformation of the vibration surface caused by the conductive joint sandwiched between the elastic body and the mounting member, a groove is formed on one surface of the mounting member so as to correspond to the region where the conductive joint is formed. A technique for forming only one portion is also known.

However, if one groove is provided in the mounting member, deformation concentrates only in one place where the groove is provided, and anisotropy of the shape occurs between the part where the groove is not provided and sufficient flatness is obtained. There was a problem that could not be obtained.
JP-A-2005-287160

  An object of the present invention is to provide a driving device, a vibration actuator, and an electronic device that can obtain stable driving characteristics.

  The present invention solves the above problems by the following means. For ease of understanding, reference numerals corresponding to the drawings showing an embodiment of the present invention are given and described, but the present invention is not limited to this.

  The invention described in claim 1 is a drive device including a vibrating body (11) that generates a progressive vibration wave on a vibrating surface (12a), and an attachment member (40) attached to the vibrating body (11). The vibrating body (11) has a flange portion (12d) on a surface different from the vibration surface (12a), and the attachment member (40) has an attachment portion (42) attached to the flange portion (12d). The part (42) is a drive device (10) characterized by having a plurality of recesses (43) in a part facing the flange part (12d).

A second aspect of the present invention is the driving apparatus according to the first aspect of the present invention, wherein the plurality of concave portions (43) are three or more.
The invention according to claim 3 is the drive device according to claim 1 or 2, wherein the flange portion (12d) has a side surface (112) of the vibrating body (11) substantially orthogonal to the vibrating surface (12a). , 113). A drive device (10) characterized in that the drive device (10) is provided.

  According to a fourth aspect of the present invention, in the driving apparatus according to the third aspect, the vibrating body (11) is attached to the piezoelectric body (13) excited by the driving signal and the piezoelectric body (13). The elastic body (12) has a flange portion (12d) on its side surface and generates a progressive vibration wave on the vibration surface (12a) by excitation of the piezoelectric body (13). The drive device (10) is characterized by this.

  The invention according to claim 5 is the drive device according to claim 4, and includes a conductive joint portion (50) having conductivity, and at least a part of the conductive joint portion (50) is a vibrating surface ( 12a) is provided on the back surface of the piezoelectric body (13) from the flange portion (12d) to electrically connect the piezoelectric body (13) and the elastic body (12), and at least one of the recesses (43). One is the drive device (10) characterized by being provided corresponding to the conductive junction (50).

  The invention according to claim 6 is the drive device according to any one of claims 1 to 5, wherein the recess (43) is a notch, and each of the recess (43) The drive device (10) is characterized in that the drive device (10) is formed along the outer periphery of the attachment portion (42) at intervals.

  The invention according to claim 7 is the drive device according to any one of claims 1 to 5, wherein the concave portion (43) is a concave groove, and each of the concave portions (43) is The drive device (10) is characterized in that the drive device (10) is formed along the outer periphery of the attachment portion (42) at intervals.

  The invention according to an eighth aspect is the drive device according to any one of the first to seventh aspects, wherein the vibrating body (11) has a through hole (through the vibration surface (12a)). 111), and the flange portion (12d) is formed on the inner surface (112) of the vibrating body (11) formed by the through hole (111). .

  The invention according to claim 9 is the drive device according to any one of claims 1 to 7, wherein the flange portion (12d) is formed on the outer surface (113). A drive device (10) characterized by

  The invention described in claim 10 is in pressure contact with the drive device (10) according to any one of claims 1 to 9 and the vibration surface (12a) of the vibrating body (11). A vibration actuator (1) including a mover (20), wherein the mover (20) is a vibration actuator (1) characterized by relative movement with a driving device (10) by a progressive vibration wave. .

An eleventh aspect of the invention is an electronic device (3) using the vibration actuator (1) according to the tenth aspect.
Note that the configuration described with reference numerals may be improved as appropriate, or at least a part thereof may be replaced with another component.

  ADVANTAGE OF THE INVENTION According to this invention, the drive device, vibration actuator, and electronic device which can obtain the stable drive characteristic can be provided.

  Hereinafter, the present invention will be described in more detail with reference to the drawings and the like. In the following embodiments, an ultrasonic motor will be described as an example of a vibration actuator.

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a view showing the appearance of a vibrating body and a mounting member shown in FIG.
The vibration actuator 1 of the present embodiment includes a stator (stator) 10 and a mover (rotor) 20 that moves relative to the stator 10. The stator 10 is included in the drive device according to the present invention.

  In FIG. 1, the driving device 10 includes a vibrating body 11 and an attachment member 40 attached to the vibrating body 11. The vibrating body 11 includes, for example, an elastic body 12 made of a metal material (for example, a steel material such as stainless steel) having a high resonance sharpness, and a piezoelectric body 13 attached to the elastic body 12 and excited by a drive signal.

  The elastic body 12 includes a vibration surface (drive surface) 12a that generates a progressive vibration wave (for example, a traveling wave having four wavelengths per revolution of the elastic body), and comb teeth 12b formed by cutting grooves in the vibration surface 12a. And a base portion 12c formed under the comb teeth 12b, an inner side surface 112 formed by a through hole 111 substantially orthogonal to the vibration surface 12a, and a flange portion 12d for fixing to the mounting member 40.

  In the figure, the vibration surface 12a is subjected to a surface treatment (plating treatment or the like) such as NiP in order to improve the wear resistance and the slidability of the moving element 20. The flange portion 12d is attached to the inner surface 112 near the center of the base portion 12c, but the attachment position is arbitrary.

  FIG. 2 is an enlarged view of the vibrating body 11 seen from the direction of arrow A in FIG. The piezoelectric body 13 is divided into an A phase 131 and a B phase 132 along the circumferential direction. In each of the phases 131 and 132, elements in which polarization is alternated every ½ wavelength are arranged. An interval corresponding to ¼ wavelength is provided between the A phase 131 and the B phase 132, and this interval portion is used as the GND unit 133.

  Returning to FIG. 1, a flexible printed circuit board (FPC) 60 for supplying a driving voltage is provided on the lower surface 13 a of the piezoelectric body 13. Each of the signal lines 61 to 63 formed in the FPC 60 is electrically connected to the A phase 131, the B phase 132, and the GND portion 133 of the piezoelectric body 13.

  The conductive joint portion 50 is made of a conductive material such as solder, for example. At least a part of the conductive joint 50 is provided from the GND portion 133 of the piezoelectric body to the flange portion 12d of the elastic body on the back surface (lower surface 13a of the piezoelectric body) side of the vibration surface 12a. Are electrically connected.

  3 is a perspective view showing the appearance of the vibrating body 11 and the attachment member 40 shown in FIG. As can be seen from FIGS. 1 and 3, the attachment member 40 includes a base portion 41 and an attachment portion 42. The attachment portion 42 is formed on one surface of the base portion 41 so as to face the flange portion 12d. The attachment portion 42 has a plurality of recesses 43 formed in a portion facing the flange portion 12d.

  In FIG. 3, the concave portion 43 is a concave groove, and is formed along the outer periphery of the attachment portion 42 at equal intervals. The attachment portion 42 is fastened to the flange portion 12d, whereby the elastic body 12 is attached to the attachment member 40. At least one of the recesses 43 is disposed corresponding to a region where the conductive joint portion 50 is formed, so that the conductive joint portion 50 is not sandwiched between the mounting portion 42 and the flange portion 12d.

  Specifically, for example, in FIG. 1, the attachment portion 42 includes a first portion (female screw) 421 and a second portion (male screw) 422 each having a corresponding thread groove, and the first portion 421. 12d is sandwiched between the first portion 422 and the second portion 422 and screwed. The first portion 421 is made of a resin material (including a polymer material) such as a resin material such as GF-containing polycarbonate, and the second portion 422 is made of a metal material such as a copper alloy, for example.

  Returning to FIG. 1, the outer ring 751 of the bearing 75 is attached to the inner side surface of the base portion 41. A shaft 71 passes through the inner ring 752 of the bearing 75. The coil spring 74 is for applying a spring force between the members 72 and 73 fixed to the shaft 71 and the inner ring 752.

  The mover 20 is made of, for example, a light metal such as aluminum, and a surface treatment such as alumite is applied to the sliding surface in order to improve wear resistance. The mover 20 is attached to a shaft 71 and is in pressure contact with the vibration surface 12 a of the elastic body by the spring force of the coil spring 74.

  As described above, the drive device (stator) 10 according to the present embodiment is configured by attaching the attachment portion 42 of the attachment member 40 to the flange portion 12 d of the vibrating body 11. The vibration actuator 1 according to the present embodiment is obtained by bringing the moving element 20 into pressure contact with the driving device (stator) 10.

  The drive device 10 according to the present embodiment generates a progressive vibration wave on the vibration surface 12a of the drive device 10 by excitation of the piezoelectric body 13, and drives the mover (rotor) 20 that is in pressure contact with the vibration surface 12a.

  Specifically, for example, when each of the drive signals whose phases are shifted by 90 ° is applied to the A phase 131 and the B phase 132 of the piezoelectric body 13, bending vibrations generated from the A phase (for example, fourth-order bending vibrations). ) And the bending vibration generated from the B phase are shifted by a quarter wavelength, and the two bending vibrations are combined, for example, four progressive vibration waves are generated on the vibration surface 12a. Further, in the illustrated embodiment, by forming comb teeth 12b on the vibration surface 12a, the neutral surface of the progressive vibration wave is brought closer to the piezoelectric body 13 side, and the amplitude of the progressive vibration wave is amplified.

  In the present embodiment, the vibration actuator 1 has the concave portion 43 in the portion facing the flange portion 12d. Therefore, by making the concave portion 43 correspond to the region where the conductive joint portion 50 is formed, The deformation of the vibration surface 12a due to this is avoided, and deterioration of the flatness of the vibration surface 12a is prevented.

  Furthermore, since there are a plurality of the concave portions 43, the deformation portions corresponding to the concave portions 43 are dispersed in the vibration surface 12a, and the deformation amount per one portion is reduced, and the shape anisotropy (vibration surface surface) is reduced. The deviation of the deformation amount depending on the position is reduced, and the flatness of the vibration surface 12a is prevented from being deteriorated.

  According to the vibration actuator 1 of the present embodiment, the contact surface between the vibration surface 12a of the elastic body 12 and the moving element 20 is excellent due to such a vibration surface with high planar accuracy, and abnormal noise is generated when the actuator is driven. The problem and the problem that the drive torque is reduced can be avoided, and stable drive characteristics can be obtained.

  In particular, when the diameter of the vibrating body 11 or the moving element 20 is reduced to, for example, about 1/3 to 1/5 times that of the prior art and the rotational speed is increased to maintain the output performance, the vibration surface 12a Since the influence of flatness is increased, the above-described excellent operational effects are remarkably exhibited.

  The number of recesses 43 is preferably three or more. When the number of the concave portions 43 is two, depending on the positional relationship of the respective concave portions 43, the vibration surface 12a may be bent in two, and the flatness of the vibration surface 12a may be reduced. This is because if the number of is 3 or more, the vibration surface 12a will not be bent and good flatness can be obtained with certainty.

  In addition, each of the plurality of recesses 43 is preferably arranged at a position where the outer periphery of the attachment portion 42 is equally divided. This is because the portions that deform corresponding to the recesses are evenly dispersed, the anisotropy of the shape is further reduced, and better flatness can be obtained.

  Since the vibration actuator according to the present embodiment has good flatness of the vibration surface 12a, the amount of sag of lapping can be reduced even when grinding is performed to improve the flatness. For this reason, there is no problem that the thin plating film formed on the vibration surface 12a is scraped off, and stable characteristics can be obtained when the motor is used.

  Furthermore, in the vibration actuator according to the present embodiment, since the sag amount of wrapping is small, it is not necessary to form a thick plating film on the surface of the vibration surface 12a in consideration of the amount scraped off by wrapping. Is shortened.

  Next, a vibration actuator according to the present invention will be described using another embodiment. In each of the embodiments described below, the same or similar reference numerals are given to portions that perform the same or similar functions as those of the vibration actuator shown in FIGS.

FIG. 4 is a partial plan view showing another embodiment. The illustrated vibration actuator is different from the vibration actuator shown in FIGS. 1 to 3 in that four recesses 43 are provided.
Since the vibration actuator of the present embodiment includes the same components as those of the vibration actuator shown in FIGS. 1 to 3, the same excellent effects can be obtained.

  Further, since the vibration actuator of the present embodiment is provided with four recesses, the vibration surface 12a corresponding to the recesses is deformed as compared with the vibration actuator of FIGS. 1 to 3 provided with three recesses. Are more evenly distributed, the deterioration of the flatness of the vibration surface 12a is further reduced, and a better flatness can be obtained.

  FIG. 5 is a partial plan view showing still another embodiment. The illustrated vibration actuator is different from the vibration actuator shown in FIGS. 1 to 4 in that a recess 43 is formed only on the outer peripheral side of the mounting portion 42.

Since the vibration actuator of the present embodiment includes the same components as those of the vibration actuator shown in FIGS. 1 to 4, the same excellent effects can be achieved.
Further, in this embodiment, the concave portion 43 is not formed on the inner periphery (inner surface) of the mounting portion 42 facing the shaft 71 (see FIG. 1), and the inner surface of the mounting portion 42 has a smooth shape with no irregularities. Therefore, the rotation characteristic of the shaft 71 is improved.

  FIG. 6 is a partial front view showing still another embodiment. The illustrated vibration actuator is different from the vibration actuator shown in FIGS. 1 to 5 in that the recess 43 is a substantially triangular notch when viewed from the side surface of the mounting member 40.

  The vibration actuator shown in FIG. 6 includes the same components as those of the vibration actuator shown in FIGS. 1 to 5, so that the same excellent effects can be obtained.

FIG. 7 is a partial front view showing still another embodiment. In FIG. 7, the recess 43 has a curved shape when viewed from the side surface of the mounting member 40.
Since the vibration actuator shown in FIG. 7 includes the same components as those of the vibration actuator shown in FIGS. 1 to 6, the same excellent operational effects can be achieved.

  FIG. 8 is a sectional view showing still another embodiment. The illustrated vibration actuator is different from the vibration actuator shown in FIGS. 1 to 7 in that a flange portion 12 d is formed on the outer surface 113 of the elastic body 12.

  Since the vibration actuator shown in FIG. 8 includes the same components as those of the vibration actuator shown in FIGS. 1 to 7, the same excellent operational effects can be achieved.

  FIG. 9 is a block diagram illustrating an embodiment of an electronic device. In the following embodiments, a camera will be described as an example of an electronic device. However, the electronic device of the present invention is not limited to an optical device such as a camera barrel, a still camera, or a video camera, but may be a communication device such as a mobile phone. There may be.

  The electronic device 3 shown in FIG. 9 generates a control signal for positioning the optical element 99 at the target position based on the drive command (target position information) supplied from the CPU and the like, the detection signal supplied from the detection unit 95, and the like. A controller 91 for generating, an oscillator 92 for generating a drive signal by a control signal supplied from the controller 91, and a phase shifter 93 for dividing the drive signal generated by the oscillator into two drive signals having a phase difference of 90 ° , Amplifiers 941 and 942 for boosting the two drive signals divided by the phase shifter 93 to desired voltages, the vibration actuator 1 according to the present invention, the optical element 99 (driver) such as a lens, and the like. And a detection unit 95 that detects position information, speed information, a driving state of the vibration actuator 1, and the like of the optical element 99.

The electronic device 3 described above operates as follows.
First, the oscillating unit 92 generates a drive signal having a desired frequency based on the control signal supplied from the control unit 91. The drive signal is divided into two drive signals having a phase difference of 90 ° by the phase unit 93, amplified to a desired voltage by the amplification units 941 and 942, and A of the piezoelectric body 13 (see FIG. 2) included in the vibration actuator 1. And B phases 131 and 132 (see FIG. 2). The piezoelectric body 13 to which the drive signal is applied is excited, and a traveling vibration wave is generated on the vibration surface 12a of the elastic body 12 by the excitation.

  The vibration actuator 1 is connected to an optical element 99 (driving body) such as a lens and drives the optical element 99. The detection unit 95 is supplied with an electrical pulse corresponding to position information of the optical element 99 from an optical encoder, a magnetic encoder, or the like attached to the optical element 99, and feeds back this to the control unit 91.

Since the electronic device 3 illustrated in FIG. 9 includes the vibration actuator 1 illustrated in FIGS. 1 to 8, it is possible to enjoy the excellent operational effects obtained by the vibration actuator 1 described above.
(Modification)
The present embodiment can be modified as follows.
(1) The drive device according to the present invention is not limited to a stator, and may be a mover or the like.
(2) In the drive device according to the present invention, it is preferable that one of the base portion 41 and the attachment portion 42 of the attachment member 40 is made of a resin material such as GF-containing polycarbonate, and the other is made of a metal material such as a copper alloy. . This is because when both are made of a metal material, abnormal noise due to chatter may occur, and when both are made of a resin material, there is a possibility that a fastening force cannot be obtained.
(3) In the present invention, the vibrating body is not limited to one that vibrates with a piezoelectric body, and may vibrate with, for example, a magnetostrictive element or the like.
(4) The vibration actuator according to the present invention is not limited to a so-called ring-type vibration actuator, and can be applied to various vibration actuators such as a so-called pencil type.

  The first to seventh embodiments and the modified examples can be used in appropriate combination, but detailed description thereof is omitted. Further, the present invention is not limited to the embodiments described above.

It is sectional drawing of Example 1 of this invention. It is the elements on larger scale of the vibration actuator shown in FIG. It is a figure which shows the external appearance of the vibrating body and attachment member of the vibration actuator shown in FIG. 10 is a partial plan view of Example 2. FIG. 10 is a partial plan view of Example 3. FIG. 6 is a partial front view of Example 4. FIG. 10 is a partial front view of Example 5. FIG. 10 is a cross-sectional view of Example 6. FIG. It is a block diagram of the Example of an electronic device.

Explanation of symbols

Drive device 10
Mover 20
Vibrating body 11
Piezoelectric body 13
Elastic body 12
Vibration surface 12a
Flange part 12d
Mounting member 40
Mounting part 42
Recess 43

Claims (11)

A driving device including a vibrating body that generates a progressive vibration wave on a vibrating surface, and an attachment member attached to the vibrating body,
The vibrating body has a flange portion on a surface different from the vibrating surface,
The attachment member has an attachment portion attached to the flange portion,
The attachment device has a plurality of recesses in a portion facing the flange portion. The drive device according to claim 1,
The drive device according to claim 1, wherein the number of the plurality of recesses is three or more. The drive device according to claim 1 or 2, wherein
The drive device according to claim 1, wherein the flange portion is provided on a side surface of the vibrating body that is substantially orthogonal to the vibration surface. A drive device according to claim 3, wherein
The vibrating body includes a piezoelectric body excited by a drive signal, and an elastic body attached to the piezoelectric body,
The elastic body has the flange portion on a side surface thereof, and generates a progressive vibration wave on the vibration surface by excitation of the piezoelectric body. The drive device according to claim 4, comprising a conductive joint having conductivity,
At least a part of the conductive joint portion is provided from the piezoelectric body to the flange portion on the back surface of the vibration surface, and electrically connects the piezoelectric body and the elastic body, and at least of the concave portion. One is a driving device provided corresponding to the conductive joint. It is a drive device given in any 1 paragraph of Claims 1-5,
The said recessed part is a notch, Each of the said recessed part is formed in the outer periphery of the said attaching part at intervals from each other, The drive device characterized by the above-mentioned. It is a drive device given in any 1 paragraph of Claims 1-5,
The said recessed part is a recessed groove, and each of the said recessed part is formed at intervals along the outer periphery of the said attaching part, The drive device characterized by the above-mentioned. It is a drive device given in any 1 paragraph of Claims 1-7,
The vibrator has a through-hole penetrating the vibration surface,
The drive device according to claim 1, wherein the flange portion is formed on an inner surface of the vibrating body formed by the through hole. It is a drive device given in any 1 paragraph of Claims 1-7,
The drive device according to claim 1, wherein the flange portion is formed on an outer surface of the vibrating body. A vibration actuator comprising: the drive device according to any one of claims 1 to 9; and a moving element that is in pressure contact with the vibration surface of the vibration body,
The moving actuator moves relative to the driving device by the progressive vibration wave. An electronic apparatus using the vibration actuator according to claim 10.