JPH07107758A - Ultrasonic actuator - Google Patents

Abstract

PURPOSE:To perform the fine movement of the title actuator by a method wherein high-frequency voltages of different phases are applied to two sets of electromechanical energy transducers, standing-wave vibrations are generated in a resonator and node parts of the standing-wave vibrations are fixed by a holding means using an elastic hinge structure. CONSTITUTION:An elastic hinge part 14 in which one pair of elastic hinge grooves 14a are formed in the other side face on the surface of a holder 7 is extended and installed integrally with the holder 7 at right angles to the generation direction of a driving force. Screw holes 15a are engraved on the surface of a fixed part 15, bolts 16 which are inserted and passed from the surface of an enclosure 12 are screwed to the screw holes 15a, and the elastic hinge part 14 is fixed to the enclosure 12. Then, the elastic hinge grooves 14a hold an ultrasonic actuator in such a way that its rigidity is weak in the direction of A and that its rigidity is strong in directions of B and C. In this state, driving voltages whose phase is deviated from each other by 90 deg. and whose resonant frequency coincides with that of an ultrasonic vibrator 5 are applied to a laminated piezoelectric element 1 for the ultrasonic actuator. Then, a sliding plate 19 which is bonded and fixed, at sliding protrusions 4, to an object 18 to be driven is frictionally driven, and the object 18 to be driven is driven in the direction of C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic actuator, and more particularly to an ultrasonic actuator which generates ultrasonic vibration by an electro-mechanical energy conversion element such as a piezoelectric element or an electrostrictive element.

[0002]

2. Description of the Related Art Conventionally, ultrasonic vibrators having various shapes have been proposed, and for example, there is one having a shape as described in JP-A-3-195377. Figure 14
It is explanatory drawing which showed the ultrasonic actuator described in this Unexamined-Japanese-Patent No. 3-195377, FIG.14 (a) is a sectional side view, FIG.14 (b) is the figure seen from the front.

As shown in this figure, the above technical means is such that three piezoelectric elements 122, 123a,
123b is fixed, and feet 132a and 132b are arranged on one surface of the resonator 121 to form an ultrasonic transducer. A pressing spring is directly arranged on the opposite surface of the foot of the resonator, and the spring 135 is fixed to the holder 133.
Due to the long holes arranged in the holder 133, the resonator 12
The pins 124a and 124b arranged at 1 are supported so as to be movable in the vertical direction. Further, the ultrasonic actuator has a structure in which the other end surface of the holder 133 is fixed to the guide plate 138 and holds the sliding plate 134.

[0004]

However, in the ultrasonic actuator disclosed in Japanese Unexamined Patent Publication No. 3-195377, the ultrasonic vibrator is vertically moved in order to transmit the pressing force of the spring to the ultrasonic vibrator. Need to be movably supported. For this reason, the structure is such that the pins are arranged on the ultrasonic vibrator and the long holes are formed in the holder. In this case, the pins, the long holes, and the ultrasonic transducers are supported so that they do not move in the movement direction of the actuator, but there is a contradiction between being able to move in the vertical direction and restricting in the driving direction. There is a risk of looseness in the long holes. This backlash is not preferable for an ultrasonic actuator that requires high accuracy, and becomes a problem particularly when positioning on the order of microns is required.

The present invention has been made in view of the above problems, and an object of the present invention is to solve the above problems of the prior art and to provide an ultrasonic actuator capable of minute movement.

[0006]

To achieve the above object, an ultrasonic actuator according to the present invention comprises two sets of electro-mechanical energy conversion elements and a resonator to which these electro-mechanical energy conversion elements are fixed. In the ultrasonic actuator for generating standing wave vibration in the resonator by applying high-frequency voltages having different phases to the two sets of electro-mechanical energy conversion elements, the constant actuator generated in the resonator is provided. The holding means for fixing the node portion of the standing wave vibration is configured by using an elastic hinge structure.

[0007]

The ultrasonic actuator according to the present invention is constituted by using an elastic hinge structure in which standing wave vibration is generated in the resonator by applying high frequency voltages having different phases to the two sets of electro-mechanical energy conversion elements. The holding means fixes the node portion of the standing wave vibration.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 are explanatory views of an ultrasonic actuator according to a first embodiment of the present invention. FIG. 1 shows the first
It is a front view showing an ultrasonic actuator of the embodiment,
FIG. 2 is a front view showing an ultrasonic transducer used in the ultrasonic actuator of the first embodiment. Also, FIG.
4A and 4B are explanatory views showing (A) resonance longitudinal vibration and (B) resonance bending vibration of the ultrasonic transducer, and FIG. 4 is a view showing a holder portion in the ultrasonic actuator of the first embodiment. FIG.

As shown in FIG. 2, in the ultrasonic transducer 5 applied to the ultrasonic actuator of the first embodiment, a brass rectangular parallelepiped resonator 2 in which a pair of laminated piezoelectric elements 1 are arranged is
As shown in FIG. 3, the resonance longitudinal vibration (A) and the resonance bending vibration (B) are simultaneously excited.

The ultrasonic vibrator 5 has a pin 3 made of quenched stainless steel and press-fitted into the vibration node of the resonator 2. In addition, the bottom surface of the resonator 2,
That is, the projection 4 for sliding is provided at the vibration antinode position on the side opposite to the surface on which the piezoelectric element 1 is arranged.

FIG. 1 is an explanatory view showing an ultrasonic actuator 6 which is a first embodiment of the present invention using the ultrasonic vibrator 5 constructed as described above.

As shown in the figure, above the ultrasonic vibrator 5, a holder 7 (see FIG. 4) made of hardened stainless steel and having a substantially U-shape is provided with its opening downward. And the ultrasonic vibration 5 is sandwiched between them.
A pair of V-shaped grooves (hereinafter referred to as V grooves) 8 are engraved on one side of the lower surface of the holder 7 (see FIG. 4).
An elastic hinge portion 14, which will be described later, is provided to extend upward on the other side of the upper surface of the holder 7. Further, on the upper surface of the holder 7, on the vertical line of the V groove 8, there is formed a circular recess 11 against which a pressing spring 10 described later abuts.

The holder 7 is held by the pin 3 of the ultrasonic transducer 5 being engaged with the pair of V grooves 8. On the other hand, the casing 1 on the axis 9 in the direction perpendicular to the V groove 8 of the holder 7
2, a pressing screw 13 is screwed into the pressing screw 13.
A pressing spring 10 is fixed to the tip of the. Furthermore, the tip end of the pressing spring 10 is engaged with the recessed portion 11 provided on the upper surface of the holder 7, and the pressing screw 13 is rotated in a predetermined direction to press the holder 7 in a predetermined direction. Pressure is activated.

When a pressing force is applied to the holder 7 by the pressing spring 10 in the axial direction 9, a predetermined pressing force is applied to the ultrasonic transducer 5 in the axial direction 9 via the pin 3. .

On the other hand, on the other side of the upper surface of the holder 7, an elastic hinge portion 14 having a pair of elastic hinge grooves 14a is formed.
Is at a right angle to the direction of thrust generation (direction C in the figure).
It is extended integrally with (see FIG. 4). The elastic hinge 1
A screw hole 15a is threaded on the upper surface of the fixing portion 15 above 4a (see FIG. 4), and a bolt 16 inserted from the upper surface of the casing 12 is screwed into the screw hole 15a, thereby elastic The hinge portion 14 is fixed to the housing 12.

The elastic hinge portion 14 is, as shown in FIG. 4, a driven body supported by a roller 17 on a casing 12 which applies a pressing force to the ultrasonic transducer 5 so as to be movable in the C direction in the figure. A sliding plate 19 made of ceramics is adhered and fixed to a contact surface of the ultrasonic transducer 5 with the sliding protrusion 4.

Next, the operation of the first embodiment will be described.

The elastic hinge 14a, which is integrally formed with the holder 7, has a low rigidity in the A direction in FIG.
The ultrasonic actuator is held in the directions C and C (see FIG. 1) with high rigidity. In this state, the ultrasonic transducer 5
The pair of laminated piezoelectric elements 1 are out of phase with each other by 90 degrees,
When a drive voltage that matches the resonance frequency of the ultrasonic transducer is applied, the sliding projection 4 frictionally drives the sliding plate 19 that is adhesively fixed to the driven body 18, and the driven body 18 in the figure
Driven in the C direction.

According to the ultrasonic actuator of the first embodiment described above, since the holder and the elastic hinge are integrally processed, there is no backlash, and the elastic hinge allows the pressing force of the pressing spring to be reduced. It does not affect the ultrasonic transducer. Also, the pressing spring and the V of the holder are
By arranging the pin of the ultrasonic transducer that engages with the groove in a straight line, the pressing force of the spring applied to the holder and the reaction force of the pressing force of the holder pressing the pin of the ultrasonic transducer are aligned. Since it exists, no rotation moment is generated in the holder.

Next, a second embodiment of the present invention will be described.

FIG. 5 is an exploded perspective view showing the structure of the ultrasonic actuator of the second embodiment. In the second embodiment, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the ultrasonic actuator of the second embodiment, a pair of holders 20 are arranged on both sides of the ultrasonic vibrator 5. An elastic hinge portion 14 is formed so as to extend on the upper surface of the rigid body portion 21 of the holder 20, and the holder 20 is fixed to the housing 12 at the elastic hinge portion 14 with bolts 16. The holder 20 is composed of a rigid body portion 21 and an elastically deformable portion 22 extending from the rigid body portion toward the tip, and a V-shaped V groove 8 is formed on the lower surface of the rigid body portion 21. The ultrasonic transducer 5 is formed by the pair of V grooves 8.
The pin 3 is held independently from the left and right.

FIG. 6 is an enlarged side view of the vicinity of the tip of the elastically deforming portion 22.

As shown in the drawing, a recess 25 is formed on the lower surface of the tip of the elastically deforming portions 22 of the pair of holders 20. In addition, at a position facing the lower surface of the tip of the elastically deforming portion 22, a pair of protrusions 2 that abut the pair of recesses 25.
A support plate 24 on which 3 is provided is disposed. The protrusion 2
3 is engaged with the concave portion 25 provided on the elastically deforming portion 22 at its tip by point support, whereby the support plate 2
4 is arranged without being separated from the elastically deforming portion 22.

Further, a screw hole 27 is threaded between the pair of protrusions 23 on the support plate 24, and the housing 12 is formed.
The tip of the bolt 26, which is inserted from the upper surface of the
It is screwed to 7. By the rotation of the bolt 26, the support plate 24 is moved in the vertical direction with respect to the elastically deformable portion 22, whereby the elastically deformable portion 22 is rocked in the vertical direction to be deformed. .

The other structure is the same as that of the first embodiment, and the description thereof is omitted here.

FIG. 7 is a front view of the second embodiment as seen from the direction E in FIG.

As shown in this figure, with the ultrasonic transducer 5 incorporated, the bolt 26 is rotated in a predetermined direction to gradually pull up the elastically deformable portion 22 of the holder 20,
Transform it. The stress corresponding to the deformation causes the elastic hinge 14
The ratio of the distance α between the a and the protrusion 23 and the distance β between the elastic hinge 14a and the V groove 8 is enlarged or reduced, and the ultrasonic transducer 5
Acts as a pressing force.

FIG. 8 is an enlarged side view of the essential parts of the second embodiment as seen from the direction D in FIG.

As shown in this figure, when the sliding protrusions 4 and the like are deformed, the holders are arranged independently of each other on the right and left sides. Press the child.

According to the ultrasonic actuator of the second embodiment, since the holder is integrally provided with the elastically deformable member, the pressing mechanism is integrated and the structure can be simplified. In addition, by providing a pair of independent holders, even if the ultrasonic transducer is attached to the sliding surface in an inclined state, the sliding plate and the sliding protrusion can be contacted while maintaining that state. Since it can be applied to the entire surface, the operation of the ultrasonic actuator is stabilized.

Next, a modification of the second embodiment will be described.

FIG. 9 is an enlarged top view of an essential part showing a modification of the ultrasonic actuator of the second embodiment, and FIG.
[FIG. 8] is a front view of a main part of the modified example.

In this modification, a pair of elastically deforming portions 22 are integrally processed from the rigid body portion 21 of the holder 28, the elastic hinge portion 14, and the end surface 29 of the rigid body portion 21, and the ultrasonic transducer is provided at the tip of the elastically deforming portion 22. A V-shaped groove 8 for holding the pin 3 of No. 5 without play is formed.

In this modification, the opposite side of the elastically deforming portion 22 of the holder 28 is pushed up by a screw 30 to deform the elastically deforming portion 22 and apply a pressing force to the ultrasonic transducer. At this time, the pair of elastic deformation portions 22 has an effect of absorbing the inclination of the ultrasonic transducer 5.

FIG. 11 is a front view showing another modification of the ultrasonic actuator of the second embodiment.

In this modification, one side portion of the holder 31, that is, on the opposite side of the V groove 8 with the elastic hinge portion 14 interposed therebetween,
Grooves 31a are alternately formed from the upper and lower surfaces at right angles to the moving direction of the ultrasonic actuator. And this holder 3
A pushing force is applied to the ultrasonic transducer by pushing up one side end portion 1 in the direction indicated by an arrow 32 in the figure.

In this modification, since the elastically deforming portion is formed by alternately providing the grooves 31a, it is possible to construct a smaller ultrasonic actuator than the above embodiment.

Next, a third embodiment of the present invention will be described.

FIG. 12 is a front view showing the ultrasonic actuator of the third embodiment, and FIG. 13 is an explanatory view showing the force generated at each part in the third embodiment. In the third embodiment, the same parts as those in the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.

In the third embodiment, the position of the hinge 33 formed on one side of the holder 34 is aligned 36 with the donating force 35 applied to the holder 34 by the thrust of the ultrasonic actuator through the pin 3. Is an example in which (see FIG. 13).

In FIG. 13, the arrow 37 indicates the pressing spring 10.
Indicates the force pressing the holder 34 downward in the figure,
The arrow 38 indicates the reaction force of the force with which the ultrasonic transducer 5 is pressed by the pressing force 37. Further, the arrow 39 indicates the above-mentioned donating power 3
5 shows a reaction force of 5.

In the third embodiment, in addition to the first embodiment, since the hinge position is aligned with the point of action of the thrust of the ultrasonic actuator, it is possible to prevent the generation of the rotation moment due to the thrust and the reaction force.

According to the third embodiment, since no rotational moment is generated in the elastic hinge, there is an effect that no deformation occurs at the hinge portion and lost motion due to deformation does not occur at the time of minute displacement.

As described above, according to each of the above embodiments, the ultrasonic linear actuator can be realized with a simple structure.
Further, the essence of the holder of the ultrasonic actuator of the above embodiment is to integrally fix the holder part and the hinge part in holding the ultrasonic vibrator. Therefore, the present invention is not limited to the ultrasonic transducer described in the present embodiment, and can be realized using all standing wave ultrasonic transducers.

It is obvious that the ultrasonic actuator of the above embodiment is not limited to the linear type, but can be applied to a rotary type ultrasonic actuator by pressing the rotating body against the elliptical vibration generating portion. .

[0048]

As described above, according to the present invention, it is possible to provide an ultrasonic actuator capable of minute movement.

[Brief description of drawings]

FIG. 1 is a front view showing an ultrasonic actuator according to a first embodiment of the present invention.

FIG. 2 is a front view showing an ultrasonic transducer used in the ultrasonic actuator of the first embodiment.

FIG. 3 (A) of the ultrasonic transducer in the first embodiment.
It is explanatory drawing which showed the resonance longitudinal vibration and (B) resonance bending vibration.

FIG. 4 is an enlarged perspective view of an essential part showing a holder part in the ultrasonic actuator of the first embodiment.

FIG. 5 is an exploded perspective view showing a configuration of an ultrasonic actuator according to a second embodiment of the present invention.

FIG. 6 is an enlarged side view of the vicinity of the tip of the elastically deformable portion in the ultrasonic actuator of the second embodiment.

FIG. 7 is a front view showing the configuration of the ultrasonic actuator of the second embodiment.

FIG. 8 is an enlarged side view of an essential part of the second embodiment as seen from the direction D in FIG.

FIG. 9 is an enlarged top view of the essential parts showing a modification of the ultrasonic actuator of the second embodiment.

FIG. 10 is an ultrasonic actuator 1 according to the second embodiment.
It is a principal part front view which showed the modification.

FIG. 11 is a main part front view showing another modified example of the ultrasonic actuator of the second embodiment.

FIG. 12 is a front view showing an ultrasonic actuator according to a third embodiment of the present invention.

FIG. 13 is an explanatory diagram showing forces generated in each part in the third embodiment.

FIG. 14 is a side sectional view (a) and a front view (b) showing an example of a conventional ultrasonic actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laminated piezoelectric element 2 ... Resonator 3 ... Pin 4 ... Sliding protrusion 5 ... Ultrasonic transducer 6 ... Ultrasonic actuator 7 ... Holder 8 ... V groove 9 ... Shaft 10 ... Press spring 12 ... Case 13 ... Press screw 14 ... Elastic hinge part 14a ... Elastic hinge 15 ... Fixed part 17 ... Roller 18 ... Driven object 19 ... Sliding plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiharu Tsubata 2-34-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Takashi Ouchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd.

Claims (1)

[Claims] 1. A pair of electro-mechanical energy conversion elements, and a resonator to which these electro-mechanical energy conversion elements are fixed, comprising: In an ultrasonic actuator that generates standing wave vibrations in the resonator by applying different high-frequency voltages, the elastic hinge structure is used as the holding means for fixing the node portion of the standing wave vibrations generated in the resonator. An ultrasonic actuator characterized by being configured.