JP2006211840A - Ultrasonic driver element and method of manufacturing ultrasonic driver element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic driver element which can prevent the occurrence of malfunction of an ultrasonic motor, and a method of manufacturing the ultrasonic driver element. <P>SOLUTION: This ultrasonic driver element has a vibrator 3 which generates vibration by being supplied with power and a drive contact part 21 which is mounted on the vibrator 3 and drives a driven part by the vibration of the vibrator 3, being brought into contact with the driven part. The drive contact part 21 is equipped with a metallic film 22 which is made of porous material and is made at the adhesive face to at least the vibrator 3 out of the face excluding the contact face 24 with the driven part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultrasonic driving element and a method for manufacturing the ultrasonic driving element.

  In recent years, an ultrasonic motor using vibration of a vibrator having a piezoelectric element has attracted attention as a new motor that replaces an electromagnetic motor. Compared with conventional electromagnetic motors, this ultrasonic motor has low speed and high thrust without gears, high holding force, long stroke, high resolution, and quietness. There are advantages such as no point, no magnetic noise, and no influence of magnetic noise.

In the above-described ultrasonic motor, a driving contact portion is disposed between the vibrator and the driven portion, and the vibration of the vibrator is transmitted to the driven portion via the driving contact portion. Since the vibration of the vibrator has an amplitude of a micrometer unit, requirements such as smoothness and wear resistance are required for the contact surface of the driving contact portion with the driven portion.
However, even if the drive contact portion satisfies the above requirements, for example, if the drive contact portion is formed from a material having properties close to the material of the driven portion, a part of the drive contact portion becomes the driven member. May cause transfer and malfunction. For this reason, various proposals have been made regarding the material of the drive contact portion suitable for driving the driven member (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-309085

In the above-mentioned Patent Document 1, a grindstone material in which alumina abrasive grains or zirconia abrasive grains are dispersed in a phenol resin is used as a material of a driving contact portion (friction element) disposed between a vibrator and a driven portion. The technique used is disclosed.
By using the grindstone material for the drive contact portion, the contact surface between the driven member and the drive contact portion can always be kept smooth by the grindstone material. Specifically, even if transfer occurs on the contact surface of the driven member, the member transferred by the grindstone material can be removed, and the occurrence of a malfunction of the ultrasonic motor can be prevented.

However, the above-described grindstone material is obtained by solidifying alumina abrasive grains, zirconia abrasive grains, or the like, which are abrasives, with phenol resin, which is a binder, and air bubbles are present therein.
When this grindstone material is fixed to the vibrator using an adhesive, the adhesive may soak into the bubbles inside the grindstone material and the adhesive may ooze out on the contact surface with the driven part. If the adhesive oozes out on the contact surface, the coefficient of friction with the driven part may change, causing a malfunction of the ultrasonic motor.
Furthermore, the driven body and the drive contact portion are bonded by the adhesive that has oozed out on the contact surface, and there is a fear that the operation of the ultrasonic motor stops.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ultrasonic driving element and a method of manufacturing the ultrasonic driving element that can prevent the operation failure of the ultrasonic motor.

In order to achieve the above object, the present invention provides the following means.
The present invention relates to a vibrator that generates vibration when supplied with electric power, and a drive that is bonded to the vibrator while being brought into contact with the driven part to drive the driven part by the vibration of the vibrator. An ultrasonic drive element having a contact portion, wherein the drive contact portion is formed of a porous material, and at least an adhesive surface with respect to the vibrator among surfaces other than the contact surface with the driven portion An ultrasonic driving element comprising a metal film formed on the surface is provided.

According to the present invention, since the adhesion between the vibrator and the drive contact portion is via the metal film formed on the drive contact portion, it is possible to prevent the adhesive from penetrating into the drive contact portion from the adhesion surface with the vibrator. Further, it is possible to prevent the adhesive from seeping out from the drive contact portion.
Further, since the drive contact portion and the vibrator are bonded via the metal film, the smoothness of the bonding surface between the vibrator and the drive contact portion can be improved, and the adhesive strength can be improved. Further, since the bonding is made between the vibrator that is a kind of metal and the metal film, the bonding strength can be improved as compared with the bonding between the vibrator and the porous material.

  Since the metal film is not formed on the contact surface with the driven part and the driving contact part is exposed, the driven part and the driving contact part can be brought into direct contact with each other. Since the drive contact portion is formed of a porous material, the contact surface between the driven portion and the drive contact portion can be kept smooth.

Moreover, in the said invention, it is desirable that the said metal film is formed in the surface adjacent to the said contact surface with the said vibrator | oscillator in the said drive contact part.
According to the present invention, since the metal film is also formed on the surface of the vibrator adjacent to the bonding surface, it is possible to prevent the adhesive from penetrating into the driving contact portion from the adjacent surface.

In the above invention, it is desirable that the vibrator includes a metal film formed on an adhesive surface with the drive contact portion.
According to the present invention, by forming a metal film on the vibrator, the adhesion between the vibrator and the drive contact portion becomes the adhesion between the metal films, and the adhesive strength can be further improved.

  In the above invention, there is provided a method for manufacturing the ultrasonic driving element of the present invention, wherein at least the vibrator among the surfaces excluding the contact surface of the porous material constituting the driving contact portion with the driven portion. It is desirable to form a metal film on the bonding surface of the two and bond the vibrator and the drive contact portion.

According to the manufacturing method of the present invention, since the vibrator and the drive contact portion are bonded via the metal film formed on the drive contact portion, the adhesive stains from the adhesion surface with the vibrator into the drive contact portion. In addition, it is possible to prevent penetration of the adhesive from the drive contact portion.
Further, since the drive contact portion and the vibrator are bonded via the metal film, the smoothness of the bonding surface between the vibrator and the drive contact portion can be improved, and the adhesive strength can be improved. Further, since the bonding is made between the vibrator that is a kind of metal and the metal film, the bonding strength can be improved as compared with the bonding between the vibrator and the porous material.
Examples of the method for forming the metal film include known coating (surface treatment) techniques such as plating and vapor deposition.

  In the above invention, the method for manufacturing an ultrasonic driving element of the present invention described above, wherein a metal film is formed on the entire surface of the porous material constituting the driving contact portion, and the vibrator and the driving contact portion are bonded. It is desirable to remove the metal film on the contact surface with the driven part.

  According to the present invention, after the metal film is formed on the entire surface of the drive contact portion, the vibrator and the drive contact portion are bonded, and the metal film on the contact surface with the driven portion is removed. Therefore, the ultrasonic driving element can be manufactured without considering the contact surface with the driven portion in the metal film forming step and the bonding step between the vibrator and the driving contact portion. That is, the metal film can be easily formed on the drive contact portion, and the manufacturing process of the ultrasonic drive element can be simplified.

  According to the ultrasonic driving element and the manufacturing method of the ultrasonic driving element of the present invention, the metal film formed on the driving contact portion and the vibrator are bonded to each other. It is possible to prevent the adhesive from bleeding and to prevent the ultrasonic motor from malfunctioning due to the adhesive.

[First Embodiment]
Hereinafter, an ultrasonic driving element according to a first embodiment of the present invention will be described with reference to FIGS. Here, description will be made by applying the ultrasonic drive element to an example of using an ultrasonic motor for driving a lens in a camera.
FIG. 1 is a cross-sectional view illustrating the overall configuration of the ultrasonic motor according to the present embodiment. FIG. 2 is a partial plan view for explaining the configuration of the ultrasonic motor of FIG.
As shown in FIGS. 1 and 2, an ultrasonic motor (ultrasonic drive device) 1 includes a piezoelectric element (vibrator, ultrasonic vibration element) 3 that generates ultrasonic vibrations when electric power is supplied, and a piezoelectric element. It is schematically configured from a case 5 in which the element 3 is housed, a driven body (driven portion) 7 that is driven by ultrasonic vibration of the piezoelectric element 3, and a presser lid 9 that presses the piezoelectric element 3.
The driven body 7 is connected to a conversion mechanism (not shown) for converting the rotational movement in a direction along the central axis C, and the position of a camera lens (not shown) along the central axis C is connected by the conversion mechanism. Moved in the direction.

  The case 5 is formed in a substantially annular shape, and an arrangement hole 11 in which the piezoelectric element 3 is arranged is formed. The arrangement holes 11 are formed in a substantially prismatic shape, and three are arranged at equal intervals on the same circumference. A guide groove 13 that is substantially perpendicular to the radial direction in the arrangement hole 11 is formed with a guide groove 15 into which a pin portion described later is inserted. The guide groove 15 is formed so as to be substantially parallel to the central axis C of the case 5.

As shown in FIG. 1, the driven body 7 is formed in a substantially annular shape, and is arranged so as to share the center axis C with the case 5. Further, a surface of the driven body 7 facing the piezoelectric element 3 is disposed so that a driving contact portion of the piezoelectric element 3 described later comes into contact.
The presser lid 9 is formed in a substantially annular shape having an edge, and is arranged so as to share the center axis C with the case 5. In addition, a plate spring of the piezoelectric element 3 to be described later is disposed on the surface of the presser lid 9 facing the piezoelectric element 3.

FIG. 3 is a diagram for explaining the constituent elements attached to the piezoelectric element of FIG. 1, FIG. 3 (a) is a diagram of the piezoelectric element viewed from the radial direction of the ultrasonic motor, and FIG. 3 (b) is a circle. It is the figure which looked at the piezoelectric element from the circumferential direction.
As shown in FIGS. 1 to 3, the piezoelectric element 3 is formed in a substantially rectangular parallelepiped shape having a long axis in the circumferential direction of the case 5. The piezoelectric element 3 includes a holding portion 17 that holds the piezoelectric element 3, a leaf spring 19 that biases the piezoelectric element 3 toward the driven body 7, and a driving contact portion that contacts the driven body 7 (ultrasonic vibration). Element) 21.

The holding portion 17 includes a wall portion 23 that holds the piezoelectric element 3 in the radial direction of the ultrasonic motor 1 and the direction along the central axis C, and a substantially cylindrical pin portion that protrudes from the wall portion 23 in the radial direction. 27.
The holding portion 17 is disposed at the approximate center that is the position of the node in the vibration of the piezoelectric element 3, and the pin portion 27 is also disposed at the approximate center that is the position of the node. For this reason, even if the piezoelectric element 3 is held by the holding portion 17, the generation of vibration of the piezoelectric element 3 is not prevented, and a decrease in vibration generation efficiency can be prevented.

FIG. 4 is an exploded perspective view for explaining the adhesion between the piezoelectric element of FIG. 1 and the drive contact portion. In FIG. 4, the vertical direction is inverted to make it easy to see the positional relationship between the drive contact portion 21 and the metal film 22.
As shown in FIG. 4, the drive contact portion 21 is formed of a grindstone (porous material) in a substantially rectangular parallelepiped shape, and a metal film 22 is formed on the adhesive surface with the piezoelectric element 3 by plating. . Moreover, the porous material which is the material of the drive contact portion 21 is exposed on the contact surface 24 with the driven body 7.
Bonding between the piezoelectric element 3 and the drive contact portion 21 is performed by bonding the piezoelectric element 3 and the metal film 22 after forming the metal film 22 on the bonding surface of the piezoelectric element 3.

  As described above, the metal film 22 may be formed only on the drive contact portion 21, or the metal film 22 may be formed on both the drive contact portion 21 and the piezoelectric element 3. When the metal film 22 is formed on both, the adhesion between the drive contact portion 21 and the piezoelectric element 3 can be further strengthened.

As described above, a plating process may be used as a surface treatment for forming the metal film 22, or the metal film 22 may be formed by vapor deposition, and is not particularly limited.
Moreover, as a grindstone which forms the drive contact part 21, the grindstone which hardened the alumina abrasive grain which is the grinding material currently mentioned by patent document 1, the zirconia abrasive grain, etc. with the phenol resin which is a binder may be sufficient. Other known grindstones may be used and are not particularly limited.

According to the above configuration, since the piezoelectric element 3 and the drive contact portion 21 are bonded via the metal film 22 formed on the drive contact portion 21, the contact surface between the piezoelectric element 3 and the drive contact portion 21 can be connected. The penetration of the adhesive can be prevented, and the adhesion of the adhesive from the drive contact portion 21 to the contact surface 24 with the driven body 7 can be prevented. Therefore, it is possible to prevent the operation failure of the ultrasonic motor due to a change in the friction coefficient between the driving contact portion 21 and the driven body 7.
Furthermore, it is possible to prevent the operation of the ultrasonic motor from being stopped due to the driven body 7 and the drive contact portion 21 being bonded by the adhesive that has oozed out on the contact surface 24.

  Further, since the piezoelectric element 3 and the driving contact portion 21 are bonded via the metal film 22, the smoothness of the bonding surface between the piezoelectric element 3 and the driving contact portion 21 can be improved. Compared with adhesion, the adhesion strength can be improved. Further, since the piezoelectric element 3 which is a kind of metal and the metal film 22 are bonded, the bonding strength can be improved as compared with the bonding between the piezoelectric element 3 and the porous material.

  In addition, as a material which forms the drive contact part 21, a grindstone may be sufficient as mentioned above, and resin may be sufficient as it. When using a resin, it is desirable to use a resin having wear resistance.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the ultrasonic motor of this embodiment is the same as that of the first embodiment, but the configuration of the drive contact portion is different from that of the first embodiment. Therefore, in this embodiment, only the periphery of the drive contact portion will be described with reference to FIGS. 5 and 6, and the description of the case and the like will be omitted.
FIG. 5 is a cross-sectional view illustrating the overall configuration of the ultrasonic motor according to the present embodiment. FIG. 6 is an exploded perspective view illustrating adhesion between the piezoelectric element of FIG. 5 and the drive contact portion. In FIG. 6, the vertical direction is inverted to make it easy to see the positional relationship between the drive contact portion and the metal film.
In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the description is abbreviate | omitted.

As shown in FIGS. 5 and 6, the ultrasonic motor (ultrasonic vibration device) 51 is generally configured by a piezoelectric element 3, a case 5, a driven body 7, and a presser lid 9.
The piezoelectric element 3 includes a holding portion 17 that holds the piezoelectric element 3, a leaf spring 19 that biases the piezoelectric element 3 toward the driven body 7, and a driving contact portion that contacts the driven body 7 (ultrasonic vibration). Element) 71.

As shown in FIG. 6, the drive contact portion 71 is formed of a grindstone (porous material) in a substantially rectangular parallelepiped shape, and a metal surface is formed by plating on the adhesion surface to the piezoelectric element 3 and a surface adjacent to the adhesion surface. A film 72 is formed. Further, the porous surface which is the material of the drive contact portion 71 is exposed on the contact surface 74 with the driven body 7.
The piezoelectric element 3 and the drive contact portion 71 are bonded by forming the metal film 72 on the bonding surface and the adjacent surface of the piezoelectric element 3 and then bonding the piezoelectric element 3 and the metal film 72 formed on the bonding surface. Is done by doing.

According to the above configuration, since the metal film 72 is also formed on the surface of the driving contact portion 71 adjacent to the bonding surface with the piezoelectric element 3, the adhesive from the adjacent surface into the driving contact portion 71 is formed. Infiltration can be prevented. Therefore, it is possible to prevent the operation failure of the ultrasonic motor due to a change in the friction coefficient between the drive contact portion 71 and the driven body 7.
Further, it is possible to prevent the operation of the ultrasonic motor 51 from being stopped due to the driven body 7 and the drive contact portion 71 being bonded by the adhesive that has oozed out on the contact surface 74.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the ultrasonic motor of this embodiment is the same as that of the second embodiment, but the method for manufacturing the drive contact portion is different from that of the second embodiment. Therefore, in this embodiment, only the method for manufacturing the drive contact portion will be described with reference to FIG. 7, and the description of the case and the like will be omitted.
FIG. 7 is an exploded perspective view for explaining the adhesion between the piezoelectric element and the drive contact portion in the ultrasonic motor according to the present embodiment. In FIG. 7, the vertical direction is shown inverted so that the positional relationship between the drive contact portion and the metal film can be easily seen.
In addition, the same code | symbol is attached | subjected to the component same as 2nd Embodiment, and the description is abbreviate | omitted.

As shown in FIG. 7, the driving contact portion (ultrasonic vibration element) 121 of the piezoelectric element 3 of the ultrasonic motor 101 is formed of a grindstone (porous material) in a substantially rectangular parallelepiped shape. A metal film 122 is formed by plating. After the metal film 122 is formed, the piezoelectric element 3 and the drive contact portion 121 are bonded. This adhesion is performed by adhesion between the piezoelectric element 3 and the metal film 122.
When the piezoelectric element 3 and the drive contact portion 121 are bonded, the metal film 122 formed on the contact surface 124 of the drive contact portion 121 with the driven body 7 is removed by a method such as processing.

  By adhering the drive contact portion 121 to the piezoelectric element 3 by the above-described method, the metal film 122 is formed on the adhesion surface to the piezoelectric element 3 and the surface adjacent to the adhesion surface, as in the second embodiment, A porous material that is a material of the drive contact portion 121 can be exposed on the contact surface 124 with the driven body 7.

  According to the above configuration, after the metal film 122 is formed on the entire surface of the drive contact portion 121, the piezoelectric element 3 and the drive contact portion 121 are bonded together, and the metal film 122 on the contact surface 124 with the driven portion 7. Has been removed. Therefore, the ultrasonic motor 101 can be manufactured without considering the contact surface 124 with the driven part 7 in the forming process of the metal film 122 and the bonding process between the piezoelectric element 3 and the driving contact part 121. That is, the metal film 122 can be easily formed on the drive contact portion 121, and the manufacturing process of the ultrasonic motor 101 can be simplified.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the present invention has been described by adapting to the driving source of the lens of the camera. However, the present invention is not limited to the driving source of the lens, but can be applied to various other driving sources. is there.

It is sectional drawing which shows the whole structure of the ultrasonic motor which concerns on the 1st Embodiment of this invention. FIG. 2 is a partial plan view showing the configuration of the ultrasonic motor of FIG. 1. It is a figure which shows the component attached to the piezoelectric element of FIG. It is a disassembled perspective view explaining adhesion | attachment with the piezoelectric element of FIG. 1, and a drive contact part. It is sectional drawing which shows the whole structure of the ultrasonic motor which concerns on the 2nd Embodiment of this invention. It is a disassembled perspective view which shows adhesion | attachment with the piezoelectric element of FIG. 5, and a drive contact part. It is a disassembled perspective view which shows adhesion | attachment with the piezoelectric element and drive contact part in the ultrasonic motor which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

3 Piezoelectric elements (vibrators, ultrasonic vibration elements)
7 Driven object (driven part)
21, 71, 121 Driving contact portion (ultrasonic vibration element)
22, 72, 122 Metal film 24, 74, 124 Contact surface

Claims (5)

A vibrator that generates vibration when power is supplied;
An ultrasonic driving element having a driving contact portion that is bonded to the vibrator and is brought into contact with the driven portion to drive the driven portion by vibration of the vibrator,
An ultrasonic driving element, wherein the driving contact portion is formed of a porous material, and includes a metal film formed on at least a bonding surface with the vibrator in a surface excluding a contact surface with the driven portion.   The ultrasonic driving element according to claim 1, wherein the metal film is formed on a surface adjacent to the bonding surface with the vibrator in the driving contact portion.   The ultrasonic drive element according to claim 1, wherein the vibrator includes a metal film formed on an adhesive surface with the drive contact portion. It is a manufacturing method of the ultrasonic drive element in any one of Claims 1-3,
A metal film is formed on at least an adhesion surface with the vibrator, in a surface excluding a contact surface with the driven portion of the porous material constituting the driving contact portion;
A method of manufacturing an ultrasonic driving element for bonding the vibrator and the driving contact portion. It is a manufacturing method of the ultrasonic drive element in any one of Claims 1-3,
Forming a metal film on the entire surface of the porous material constituting the drive contact portion;
Bonding the vibrator and the drive contact portion,
A method for manufacturing an ultrasonic driving element, wherein the metal film on a contact surface with the driven part is removed.

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