JPH11235058A - Vibrator and vibraton wave actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrator which can eliminate a continuity defect caused by the breakage of a flexible printed board and has high reliability. SOLUTION: A vibration device has a layered piezoelectric device 5, a flexible printed board 6 connected to the layered piezoelectric device 5, and two elastic elements between which the piezoelectric device 5 and the flexible printed board 6 are held. A driving alternating signal is applied to the layered piezoelectric device 5 through the flexible printed board 6 to excite vibration. The flexible printed board 6 has a part held between one of the elastic elements and the layered piezoelectric device 5 and a part extended outward from the held part. A shaping member 22 by which a bent part of the flexible printed board 6 is smoothly warped is attached to a boundary position between the held part and extended part of the flexible printed board 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating body and a vibrating wave actuator, and more particularly to a vibrating body for making electrical connection with a vibrating body by a flexible printed circuit board.

[0002]

2. Description of the Related Art FIG. 6 is a side view of a vibrating body constituting a rod-shaped vibration wave actuator as a conventional vibration wave actuator. The rod-shaped vibrator includes a first elastic body 2 and a second elastic body 3 made of metal, a laminated piezoelectric element 5 interposed therebetween, and a holding portion 6d of a flexible printed board 6 shown in the figure. Thus, the elastic members 2 and 3 are tightened by the shaft 4 inserted into the central portion to form an integral structure.

[0003] The laminated piezoelectric element 5 is composed of a plurality of piezoelectric ceramic layers having an electromechanical energy conversion element function and an electrode layer, which are alternately superposed on each other, and a plurality of electrodes (for example, five dots) exposed on one surface. The contact pattern of the connection portion 6c of the flexible printed circuit board 6 is brought into contact with the electrode of the flexible printed circuit board 6 to enable electrical connection in one place. When a driving alternating signal is applied to the laminated piezoelectric element 5 by the flexible printed circuit board 6,
The laminated piezoelectric element 5 repeats expansion and contraction displacement in the thickness direction, so that a plane orthogonal to the axial direction of the vibrating body is formed.
The bending vibrations in two directions are excited, and the combined vibrations generate an elliptical motion on the driving surface 2a of the vibrating body. It is designed to move.

FIG. 5 shows a configuration of the flexible printed circuit board 6. The flexible printed circuit board 6 includes the rod-shaped vibrator 1
The conducting portion 6b extends from the holding portion 6a which is fastened and held by the second elastic body 3 and the laminated piezoelectric element 5 constituting
For example, the extending end of the conducting portion 6b has a connecting portion 6c for connecting to a not-shown conducting connector, and covers the area covered with the cover coat portion 18 indicated by an arrow except for necessary portions to electrically Insulation is performed.

[0005]

However, in the structure of the above-mentioned conventional flexible printed circuit board,
When assembling the rod-shaped ultrasonic vibrator, cutting occurs at the protruding portion of the flexible printed circuit board from the vibrator during driving,
A conduction failure has occurred. This is caused by a force that bends the flexible printed circuit board in an out-of-plane direction during assembly and driving of the rod-shaped ultrasonic vibrator.

Originally, the width of the flexible printed board 6 should be widened, but in consideration of the use environment of the vibrating body of the rod-shaped vibrating wave motor, the flexible printed board is formed of another structure (for example, a motor is mounted). This causes a problem of interference with members constituting the drive device and the device case.

The rod-shaped vibrator converts electrical energy into mechanical vibration energy to obtain a mechanical output, and an increase in the loss of vibration energy is directly related to the performance of the rod-shaped vibrator.

On the other hand, the flexible printed circuit board uses a relatively soft material such as a polyimide resin for the base, and an increase in the mass of the flexible printed circuit board causes an increase in energy loss of the rod-shaped vibrator. It is not desirable because it causes a decrease in body performance.

An object of a first invention according to the present application is to provide a highly reliable vibrating body which prevents conduction failure due to breakage of a flexible printed circuit board.

An object of a second invention according to the present application is to provide a highly reliable vibration wave actuator which prevents conduction failure due to breakage of a flexible printed circuit board connected to a vibrator.

[0011]

A first configuration for realizing the object of the first invention according to the present application is an electric-mechanical energy conversion element, and is electrically connected to the electro-mechanical energy conversion element. Having a flexible substrate and an elastic body,
In a vibrating body that excites vibration by applying an alternating signal for driving to the electro-mechanical energy conversion element through the flexible substrate, the flexible substrate is formed by the elastic body and the electro-mechanical energy conversion element. An extending portion extending outward for electrical connection from a holding portion sandwiched therebetween, and having a bent portion of the extending portion curved at a boundary position between the holding portion and the front extending portion. It is provided with a guide member for guiding.

[0012] The guide member is an elastic member, and the elastic member is an adhesive or a rubber member that can be flexibly elastically deformed.

A configuration of a vibration wave actuator that achieves the object of the second invention according to the present application includes a vibrating body having any one of the above configurations.

The above-mentioned vibration wave actuator has a contact member which comes into pressure contact with a driving surface of the vibration member, and moves the vibration member and the contact member relatively.

Further, the contact body of the vibration wave actuator is arranged coaxially with the vibration body.

According to the above configuration, durability against bending applied to the flexible printed circuit board and cutting resistance can be improved, and conduction failure due to cutting can be prevented.

Thus, it is possible to provide a highly reliable vibrating body such as a bar-shaped vibrating body and a vibration wave actuator.

Further, according to the above configuration, the flexure applied to the flexible printed circuit board by a simple and inexpensive method of applying an adhesive to a place where the bending stress of the flexible printed circuit board generated near the holding portion of the conductive portion occurs. It is possible to improve the durability against music and the cutting resistance, and prevent poor conduction due to cutout.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a longitudinal sectional view of a rod-shaped vibrating body 1 according to a first embodiment of the present invention. The configuration of the rod-shaped vibrator 1 is the same as that of the conventional example shown in FIG. 6, and the description is omitted. The basic configuration of the flexible printed circuit board 6 used in the present embodiment is the same as that of the conventional example shown in FIG. 5, and the flexible printed circuit board 6 includes the second elastic body 3 forming the rod-shaped vibrator 1. A conducting portion 6b extends from a holding portion 6a which is sandwiched and clamped by the laminated piezoelectric element 5. For example, a connecting portion 6c for connecting to a not-shown conducting connector is provided at an extending end of the conducting portion 6b.
Are formed and covered by the cover coat portion 18 in the region indicated by the arrow except for the necessary portions, so as to perform electrical insulation.

In this embodiment, the vibrating body 1 is driven by applying a drive signal to the two-phase driving piezoelectric elements of the laminated piezoelectric element 5, and each driving phase has an independent ground phase. In addition, since a sensor phase for use as a sensor for detecting a vibration state is provided, a total of five phases are electrically connected to the outside.

Since all of the electrical connections are made by the flexible printed circuit board 6, the flexible printed circuit board 6 has five substrate electrodes 17 formed thereon. The driving method of the vibrating body 1 shown here, the configuration of the laminated piezoelectric element 5, and the like are as described above, and thus description thereof will be omitted.

The base of the flexible printed circuit board 6 of this embodiment is formed of a polyimide resin and has a thickness of about 2
5 μm.

Electrode 17 of flexible printed circuit board 6
Is formed of a copper foil and has a thickness of about 35 μm. The exposed portion of the copper foil is plated with solder to prevent oxidation of the copper foil. Cover coat portion 18 for insulation provided to conductive portion 6b of flexible printed circuit board 6
Is formed of a polyimide resin and has a thickness of about 25 μm.
It is. The electrode 17 of the flexible printed circuit board 6 is formed by being adhered on a base material with an adhesive.
Epoxy adhesive is used and the average thickness is 15
μm.

The diameter of the rod-shaped vibrator 1 is φ10 mm,
The diameter of the holding portion 6a of the flexible printed circuit board 6 is also φ1.
It is formed at 0 mm. From the center of the holding portion 6a to the connecting portion 6c
Is about 40 mm up to the end of. The width of the conductive portion 6c is about 3.25 mm. The width of each of the electrodes 17 formed on the conductive portion 6c is about 0.25 mm and the pitch is about 0.5 mm
It is.

When assembling the rod-shaped vibrator 1 into an actual device, the conductive portion 6b of the flexible printed circuit board 6 is arranged, for example, along the side surface of the laminated piezoelectric element 5 or the first elastic body 3 due to restrictions on arrangement. Is done.

For this reason, as described above, the flexible printed circuit board 6 bends the conductive portion 6b as an extension extending from the vibrator.

As described above, if the width or thickness of the connecting portion 6c of the flexible printed board 6 is increased, the loss of vibration energy due to the flexible printed board 6 is increased, and the performance of the vibrating body is reduced. Further, in consideration of the usage state of the rod-shaped vibrating body 1, the width of the conductive portion 6b of the flexible printed circuit board 6 cannot be increased beyond the above value.

In the present embodiment, the flexible printed circuit board 6 is provided with a holding member as a guide member having an R-shaped outer peripheral surface at an extending portion 6d at a boundary position extending from the holding portion 6a to the outside of the vibrating body 1. 22 are bonded and bent at the extension 6 d of the flexible printed circuit board 6.
Except for the bending force being concentrated at the bent portion, by dispersing this force, conduction failure due to cutout of the flexible printed circuit board 6 is prevented, and a highly reliable rod-shaped vibrator is realized.

The material of the holding member 22 can be arbitrarily selected, but is preferably an elastic member in order to disperse the bending force generated at the bent portion. For example, synthetic rubber, vinyl chloride,
A certain effect can be obtained by selecting an organic material such as polycarbonate.

In the present embodiment, the laminated piezoelectric element 5 is employed as the piezoelectric element. However, the present invention is not limited to this, and a piezoelectric element composed of a single plate may be used. The shape of the vibrator 1 and the shape and dimensions of the vibrator 1 and the flexible printed circuit board 6 are not limited to the present embodiment.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.

FIG. 2 shows a sectional view of a rod-shaped vibration wave motor.
The first with a hole coaxial with the outer shape in the center of each
The laminated piezoelectric element 5 and the flexible printed circuit board 6 are sandwiched between the elastic body 2 and the second elastic body 3, and the flange portion 4a of the shaft 4 and the nut 7 penetrating the holes,
A Langevin type vibrator is formed by tightening the elastic bodies 2 and 3, the shaft 4 and the laminated piezoelectric element 5.

In the Langevin vibrator, when the clamping force between the elastic members 2 and 3, the shaft 4 and the laminated piezoelectric element 5 fluctuates, the vibration characteristics change, which affects the characteristics when used in a vibration wave actuator.

Therefore, in order to stabilize the characteristics of the actuator, it is important to stabilize the tightening force between the shaft 4 and the nut 7.

In this embodiment, as shown in FIG. 3, the members 2 to 5 constituting the vibrating body 1 are temporarily assembled, and then the vibrating body 1 is placed on an assembly jig 31. The nut 7 is tightened while a preload of approximately 300 kgf is applied to the members 5 to 5. By assembling the vibrating body 1 in this manner, it is possible to eliminate the influence of the variation in the pressing force caused by controlling the tightening torque with respect to the nut, so that a stable holding force of the vibrating body can be given.

Since a desired clamping force can be obtained even if the tightening torque of the nut 7 is small, it is desirable that the preload is as large as possible.

FIG. 4 shows the configuration of the laminated piezoelectric element according to the present embodiment.

The laminated piezoelectric element 5 has a laminated structure of a piezoelectric element plate, and an AC voltage is applied to each of the upper and lower electrodes of the piezoelectric element in the piezoelectric element plate in which electrodes are formed on one side of each layer of the piezoelectric element. By doing so, a generating force can be obtained.

In FIG. 4, the piezoelectric element plates 19-1 to 19-19
-N is a driving and vibration detecting piezoelectric element plate, and conduction of each layer is obtained by through holes.

Through-holes formed in the piezoelectric element plate 19-1 establish electrical continuity with the outside. In the present embodiment, the through-holes are brought into pressure contact with the flexible printed circuit board 6 on which the electrodes 17 corresponding to the respective through-holes are formed. Conduction takes place.

The piezoelectric element plate 19-3 includes electrodes A, A ',
B, B 'and S are formed and used for driving or vibration detection, and through holes formed in the piezoelectric element plate 19-1 via the piezoelectric element plate 19-2 and the piezoelectric element plate 19-3 and below. It also has a function as a wiring pattern that is used for connection with the electrode section.

An electrode S for detecting vibration is formed on the piezoelectric element plate 19-4.
'Makes the sensor use.

Electrodes A and B are formed on the piezoelectric element plate 19-4 with a substantially cross-shaped insulating portion therebetween, and are divided into four regions together with the electrodes S. The electrodes A ',
B ′ is formed.

In the piezoelectric element plates 19-5 to 19- (n-1), a pattern is formed with a substantially cross-shaped insulating portion interposed therebetween.
It is divided into four areas.

The electrodes of these four regions and the piezoelectric element plate 19
In -3 electrodes A and B, the opposing regions are used for A-phase driving and B-phase driving, respectively.

The reason why the electrodes are divided into four regions in the laminated piezoelectric element 5 is to effectively use the driving force of the vibration wave actuator. A detailed description is omitted here.

The electrodes facing the central axis are polarized in opposite directions.

The piezoelectric element plate 19-n is provided as a processing allowance when processing for smoothing the end face of the laminated piezoelectric element 5 is performed.

The piezoelectric element plates 19 are integrally fired to form the laminated piezoelectric element 5.

On the other hand, in FIG.
Is anodized, and is joined to a spring case 9 made of an iron-based metal by an adhesive or the like. The spring case 9 is provided with a cylinder portion for guiding the spring and a flange portion below the cylinder portion for receiving the spring. The compression spring 14 is sandwiched between the flange portion and the lower portion of the gear 11 and compressed.
The rotor 8 is pressed against the gear 11 against a friction ring (not shown) of the elastic body 2.

The gear 11 is positioned in a thrust direction by a motor mounting flange 12 positioned by a positioning step provided on the shaft 4 and a nut 13 for fixing the motor mounting flange 12. , A rotary sliding portion is formed and is rotatably supported.

In driving the vibration wave actuator having the above structure, when a two-phase AC signal having a phase shift from a power supply (not shown) is applied to the laminated piezoelectric element 5, bending vibration in two directions with respect to the longitudinal direction of the shaft 4 is generated by the elasticity. Excited by the body, the elastic body generates bending vibration. At this time, an elliptical vibration occurs at the contact portion of the first elastic body 2 with the rotor 8, whereby the rotor 8, the spring case 9, and the gear 11 rotate integrally. The spring case 9 is provided with two grooves 9a in the radial direction.
Since the protrusions 11a are fitted without play, the rotor 8
Is transmitted to the gear 11 without loss.

The vibration wave actuator is fastened to the mounting table 16 via the flange 12 with the screw 15 and incorporated into the device. The mounting base 16 also has a substrate support 16a for fixing the flexible printed circuit board 6.

The flexible printed circuit board 6 includes a connecting portion 6
At the part b, it is fixed to the substrate support part 16a with an adhesive.

Projection 6d of flexible printed circuit board 6
The adhesive 21 as a guide member for bending and deforming in a curved shape is applied in advance to the surface having the electrodes and the side surfaces of the laminated piezoelectric element 5. The adhesive 21 prevents the bending force from concentrating on the protruding portion 6d even if the flexible printed circuit board 6 is subjected to bending deformation, thereby preventing conduction failure due to breakage and realizing a highly reliable vibration wave actuator.

The adhesive 21 used here is required to have adhesiveness to polyimide and ceramic which are base materials of the flexible printed circuit board.

Further, it is required that the workability of bending the flexible printed circuit board is not impaired, and that the bending force is prevented from being concentrated on a part and the force is dispersed.

In this embodiment, a good vibration wave actuator is realized by using a synthetic rubber adhesive such as chloroprene rubber or nitrile rubber to satisfy the conditions of adhesiveness, workability and dispersion of force. did.

By applying the adhesive 21 in this manner,
It is possible to realize a rod-shaped vibrating body or a vibrating wave actuator which is excellent in reliability and does not cause breakage in the flexible printed circuit board 6.

The material used as the adhesive 21 is not limited to the present embodiment. For example, a hot melt adhesive can be used to improve workability, and the material can be arbitrarily selected as long as the use conditions are satisfied.

As another example, simple silicone rubber or synthetic rubber may be used.

[0062]

According to the present invention, it is possible to provide a highly reliable, for example, rod-shaped vibrator, which prevents conduction failure due to cutout of the flexible printed circuit board.

Further, it is possible to prevent poor conduction due to breakage of the flexible printed circuit board and to provide a highly reliable, for example, a bar-shaped vibrator easily and inexpensively.

Furthermore, a highly reliable vibration wave actuator can be provided.

[Brief description of the drawings]

FIG. 1 is a side view of a vibrating body according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a vibration wave actuator according to a second embodiment.

FIG. 3 is a diagram showing a method of assembling a vibrating body according to a second embodiment.

FIG. 4 is an exploded perspective view showing a configuration of a laminated piezoelectric element according to a second embodiment.

FIG. 5 is a plan view showing a configuration of a flexible printed circuit board.

FIG. 6 is a sectional view of a conventional vibrating body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration body 2 1st elastic body 3 2nd elastic body 4 shaft 5 laminated piezoelectric element 6 flexible printed circuit board 7 nut 12 flange 16 mounting base 17 electrode 18 cover coat part 19 piezoelectric element board 21 adhesive 22 holding member

Claims (8)

[Claims] 1. An electro-mechanical energy conversion device comprising: an electro-mechanical energy conversion device; a flexible substrate electrically connected to the electro-mechanical energy conversion device; and an elastic body, wherein the electro-mechanical energy conversion is performed via the flexible substrate. In a vibrating body that excites vibration by applying an alternating signal for driving to an element, the flexible substrate is configured to electrically discharge outward from a holding portion that is held between the elastic body and the electro-mechanical energy conversion element. And a guide member for guiding a bent portion of the extending portion in a curved shape at a boundary position between the holding portion and the front extending portion. Vibrating body. 2. The vibrating body according to claim 1, wherein the guide member is an elastic member. 3. The vibrating body according to claim 2, wherein the guide member is an adhesive. 4. The vibrating body according to claim 2, wherein the guide member is a rubber member that can be elastically deformed. 5. The vibrating body according to claim 1, wherein the extending portion of the flexible printed circuit board is disposed along a fixing member at a front end side from the bent portion. . 6. A vibration wave actuator comprising the vibrating body according to claim 1, 2, 3, 4, or 5. 7. The vibration wave actuator according to claim 6, further comprising a contact body that presses and contacts a driving surface of the vibration body, and relatively moves the vibration body and the contact body. . 8. The vibration wave actuator according to claim 7, wherein the contact body is arranged coaxially with the vibration body.