JPH06261562A - Oscillation-wave actuator - Google Patents

Abstract

PURPOSE:To provide an oscillation-wave actuator wherein its cost is low, its working property is good, its durability is high and its reliability is high by eliminating a drawback that a flexible printed-circuit board as a connecting conductor which connects a piezoelectric element to a drive circuit is expensive, easily breakable and the like in an oscillation-wave actuator (an ultrasonic motor) in conventional cases. CONSTITUTION:Conductive conductors 17a to 17d (thin sheetlike conductors) which are not insulated and covered are used instead of a flexible printed-circuit board, and a base stand 19 which fixes an oscillation body 3 and a case 20 which surrounds the whole are constituted of an insulating material. A rotor is represented by 4, a vibration-proof rubber by 5, a spring by 6, and a shaft which is fixed to the rotor 4 by 11, respectively. Thereby, since the metal conductors are used instead of the flexible printed-circuit board as connecting wires which connect a piezoelectric element 2 to a drive circuit, the attachment working property of the title actuator is improved, its cost is lowered. and its reliability and its durability are improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a frequency actuator (or ultrasonic motor).

[0002]

2. Description of the Related Art The structure of a conventionally known vibration wave actuator will be described with reference to FIGS.

In FIGS. 8 and 9, reference numeral 1 denotes a disc-shaped or wheel-shaped vibrating body, which is made of elastic metal, and a thick portion of its outer peripheral edge causes vibration. It is a division. Reference numeral 2 denotes an annular piezoelectric element adhered to the lower surface of the annular thick portion (that is, the vibration generating portion) of the vibrating body main body 1. On the lower surface of the piezoelectric element 2, the element and a control circuit (drive circuit not shown) are provided. ) Is bonded to the flexible printed circuit board 12 (hereinafter abbreviated as “flexible”). The vibrating body 3 is composed of the vibrating body 1 and a piezoelectric element (vibration generating element) 2, and the vibrating body 1 is fixed on the boss portion 9a at the center of the motor base 9 at the center of itself. Has been done.

Reference numeral 4 denotes a moving body (that is, a rotor) which is pressed against an annular vibration generating portion of the vibrating body 1 by a spring 6, and the moving body 4 is pressed against the vibrating portion of the vibrating body 1 at its outer peripheral edge. Has been.

An anti-vibration rubber 5 is attached on the moving body 4, and the spring 6 pushes the moving body 4 through the rubber 5.
The moving body 4 has a disk shape or a wheel shape, and a drive shaft 11 is fitted in a hole at the center thereof, and the shaft 11 is a base 9
It is rotatably supported by a bearing 8 fixed to the motor and a bearing 7 attached to the motor case 10.

The flex 12 has a planar shape as shown in FIGS. 8 and 10, and has a conductive pattern 13 to be wiring and electrodes 14 and 15 on the conductive pattern.
Reference numeral 16 shown in FIG. 9 is a reinforcing plate that strengthens the substrate at the position of the electrode 14.

FIG. 11 shows an enlarged sectional view of the flexible cable 12.
In FIG. 11, reference numeral 12a is a base film and 12b is a cover film, which are generally made of a polyimide film having a thickness of 25 μm. 13 is a printed wiring (that is, a conductive pattern), which is usually 35 μm
Made of thick copper foil. Reference numeral 12c is an adhesive layer, and the conductive pattern 13 is sandwiched between the base film 12a and the cover film 12b by the adhesive layer 12c.
An opening is formed in the cover film 12a and the adhesive layer 12c at the position of the electrodes 14 and 15, and an electrode is formed on the conductive pattern 13 exposed in the opening.

[0008]

The conventional vibration wave actuator described above has the following drawbacks.

The flex has extremely low mechanical strength and therefore requires great care in handling, but even with such caution, there is a high risk of breaking or damaging during the assembly work.

Since the price of flex is very high, it is one of the factors that increase the cost of the vibration wave actuator.

The flexible electrode 14 is connected to an external circuit by soldering, but the adhesive layer 12c is melted by the heat of soldering and the conductive pattern 13 and the cover film 12 are melted.
Sometimes b was peeled off.

When the optical equipment equipped with the vibration wave actuator is used in a high temperature environment or a high humidity environment, the adhesive layer 12c may be peeled off, the adhesive strength may be lowered, or the adhesive layer Due to the moisture absorption, the insulation resistance between adjacent conductive patterns is reduced, and as a result, a short circuit may occur between the wirings, possibly damaging the motor.

Generally, the manufacturer's guaranteed heat resistance temperature of the flexi is 260 ° C. for 10 seconds or less. Therefore, the temperature management of the soldering iron and the soldering work are restricted, and the workability is poor.

It is an object of the present invention to provide an improved oscillatory wave actuator that does not have the above drawbacks.

[0015]

In order to realize a vibration wave actuator that does not have the above-mentioned drawbacks, the present invention decides to design a motor structure based on the following basic principle.

That is, the use of flex for the electrical connection between the piezoelectric element and the external circuit is abolished, and a conductor such as a thin metal plate of phosphor bronze or stainless steel is used instead. Further, an insulating material such as a resin is used as a constituent material of the motor base and the case, and the insulating coating on the wiring side is not required, thereby simplifying the structure.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. In the embodiments described below, the same components as those of the prior art are represented by the same reference numerals,
Moreover, description of the same components will be omitted unless necessary.

1 to 4 show the structure of the vibration wave actuator of the first embodiment of the present invention. In the actuator of this embodiment, the base 19 and the case 20 are made of an insulating material such as resin, and thin plate electrode conductors 17a to 17d made of phosphor bronze are used in place of the flex used in the conventional actuator. Has been done. The conductor 17a is fixed to the surface of the base 19 so as to be connected to the A-phase electrode of the piezoelectric element 2, and the conductor 17b is arranged so as to be connected to the B-phase electrode of the piezoelectric element. The conductor 17c for the sensor is arranged in the area of the sensor phase for the detection. Moreover, as shown in FIG.
A conductor 17d for reference potential is arranged at a position 180 degrees away from the arrangement position of the external connection terminal portion of 17c,
An annular portion at the tip of the conductor 17d is disposed on the cylindrical boss portion (vibration body support portion) 19a of the base 19 and is sandwiched between the vibration body 1 and the boss portion 19a of the base 19. It has become so. The conductor 17d is a conductor for dropping the potential of the vibrating body 1 to the reference potential of the drive circuit, and the external connection terminal of the conductor 17d is connected to the reference potential portion of the drive circuit.

As shown in FIG. 3, holes 17e are formed through the external connection terminals of the conductors 17a to 17d arranged on the outer peripheral edge of the base 19. The pin-shaped projection 19b projectingly provided on the base 19 at a position corresponding to the hole is
The conductors 17a to 17d are fixed to the base 19 by heating and crushing the tips of the protrusions 19b after the conductors 17a to 17d are inserted into the base plate 19. Then, lead wires (not shown) are soldered to the end portions of the conductors fixed to the base 19 in this manner, and the conductors 17a to 17d are connected to the drive circuit (not shown) via the lead wires.

In the vibration wave actuator of this embodiment described above, a band conductor made of phosphor bronze is used in place of the flexible member without any insulating coating, and the base 19 and the case 20 are made of an insulating material such as resin. Since the conductors 17a to 17d are attached, there is no risk of cutting or damage to the conductors, and since it is not necessary to use an adhesive at the time of attachment, workability is good, and as a result, manufacturing efficiency and manufacturing cost are reduced. It is possible to improve the reliability and durability of the actuator.

FIG. 5 shows a modification of the connecting portion between the conductors 17a to 17d and the base 19 and the vibrating body 3. The conductor fixing portion of the base 19 and the conductor fixing portion of the vibrating body 3 are shown in FIG. Between the conductors 17a to 17d, a curved portion 17f that bends in the concave direction of the base 19 is formed.
The vibration of the vibrating body 3 is absorbed by f so that the vibration characteristics of the vibrating body 3 are not affected.

FIG. 6 shows a second embodiment of the present invention. In this embodiment, the base 19 and the case 20 are made of an insulating material, which is the same as the previous embodiment, but the base 19
Fixed portions of the conductors 17a to 17d in FIG.
The external connection structure in is different from the above embodiment. That is, in this embodiment, as shown in FIG. 6B, an L-shaped pin 18 is previously provided on the outer peripheral edge portion of the base 19.
One end 18a of the pin 18 projects from the end surface of the base 19, and the other end 18b of the pin 18 projects from the outer peripheral surface of the base 19.

When mounting the conductors 17a to 17d,
The hole 17e of the external terminal portion of each conductor is provided with the protruding portion 18 of the pin 18.
It is fitted to a, and the solder 21 is built up on the protruding portion 18a of the pin to electrically connect the pin 18 and the conductors 17a to 17d. Then, the piezoelectric element 2 is connected to the drive circuit by soldering a lead wire (not shown) or the like to the pin protruding portion 18b protruding on the outer peripheral surface of the base 19.

FIG. 7 shows a thin wire conductor 2 instead of the above-mentioned thin plate conductor.
2 shows the case where 2 is used, and the conductors 22a ...
Only the relative position of 22d and the piezoelectric element 2 is shown. 22a is a conductor connected to the A phase of the piezoelectric element 2, 22b is a conductor connected to the B phase of the piezoelectric element 2, 22c is a conductor connected to the sensor phase of the piezoelectric element 2, and 22d is the potential of the base 19. It is a conductor for dropping to the reference potential of the drive circuit, and corresponds to the above-mentioned conductors 17a to 17d.

[0025]

As described above, in the vibration wave actuator of the present invention, as a connecting conductor for electrically connecting the piezoelectric element and the drive circuit, a metal (conductive Since the conductor is used without an insulating coating, the following effects can be obtained.

(1) The conductor made of metal or the like is much cheaper than the flexible one and is free from the risk of cutting or damage. Therefore, the workability is good and the manufacturing efficiency of the vibration wave actuator is improved, resulting in a large manufacturing cost. Can be reduced to

(2) Since a conductor having high mechanical strength is used and fixed by soldering, there is no risk of damage to the conductor even if it is repeatedly used in a high temperature environment or a high humidity environment.
There is no risk of electrical failure of the actuator, and the reliability and durability of the device equipped with the actuator can be improved.

(3) Since there is almost no temperature restriction on the conductor, the efficiency of the soldering work can be improved and the efficiency of the assembling work of the actuator can be improved.

(4) Since the adhesive is not used for attaching the conductor, there is no contamination of the work environment due to the dripping of the adhesive, and therefore the quality control accuracy is improved and the reliability of the actuator is improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a vibration wave actuator according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of conductors with respect to a piezoelectric element 2 in the actuator of FIG.

3 is an enlarged vertical sectional view of a part of FIG.

FIG. 4 is a half longitudinal sectional view of the vibration wave actuator shown in FIG. 1 in an assembled state.

FIG. 5 is a view showing a modified example regarding the shape of a conductor in the actuator.

FIG. 6A is a half longitudinal sectional view of a vibration wave actuator according to a second embodiment of the present invention. (B) is an enlarged view of a part of FIG.

FIG. 7 is a diagram showing a modified example showing a case where a thin wire is used as a conductor.

FIG. 8 is an exploded perspective view showing an example of a conventional vibration wave actuator.

FIG. 9 is a longitudinal sectional view of a half portion of the vibration wave actuator of FIG.

10 is a plan view of a flexible printed circuit board used in the actuator of FIG.

FIG. 11 is an enlarged cross-sectional view of the flexible printed board.

[Explanation of symbols]

1; Vibrating body 2; Piezoelectric element 3; Vibrating body 4; Moving body 5; Anti-vibration rubber 6; Springs 7, 8; Bearings 9, 19; Base 10, 20; Case 11; Shaft 12; Flexible printed circuit board 14 , 15; electrodes 16; reinforcing plates 17a to 17
d; thin conductor 17e; hole 18; pin 21: solder 22a to 22
d; Fine wire conductor

Claims (4)

[Claims] 1. A vibrating body to which a vibration generating element such as a piezoelectric element is fixed, a moving body that is pressed against a vibrating surface of the vibrating body to move by vibration of the vibrating body, the vibration generating element and a control circuit. And an electrical connection member for connecting the electrical connection member to the vibrator and the moving body in an electrically insulated case in which the electrical connection member is formed of a conductive thin plate. A vibration wave actuator, wherein: 2. The vibration wave actuator according to claim 1, wherein the electrical connection member is a conductive thin wire. 3. The vibration wave actuator according to claim 1, wherein the case is made of a conductor, and an insulating coating is applied to an inner surface of the case. 4. The case is made of a conductor, and an insulating coating is applied to the inner surface of the case.
Vibration wave actuator.