JPH06210244A - Ultrasonic vibrator and ultrasonic actuator - Google Patents

Abstract

PURPOSE:To excite strong vibration in an elastomer and to enable efficient driving by providing the elastomer, a fixing member and an exciting means and constituting the exciting means of a lamination type piezoelectric element and the load mass body fixed to the end part thereof. CONSTITUTION:An elastomer 5 is held and fixed at the nodes 6 in its resonance bending vibration by fixing members 7 and a lamination type piezoelectric element 9 is bonded and fixed at a vibration loop position 8 and a load mass member 10 is bonded and fixed to the end surface of the piezoelectric element 9 and an exciting means 11 is constituted of the lamination type piezoelectric element 9 and the load mass member 10. When ultrasonic vibrator thus constituted is driven by the resonance bending vibration frequency of the elastomer 5 by an external power supply, it is excited in the lamination direction of the lamination type piezoelectric element 9. At this time, reaction force is applied to the piezoelectric element 9 by the inertial force of the load mass member 10 and becomes the exciting force of the elastomer 5 to strongly excite the elastomer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vibrator and an ultrasonic actuator which generate 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, various structures of ultrasonic transducers and ultrasonic actuators have been proposed. For example, Japanese Patent Laid-Open No. 2-209340 discloses ultrasonic vibrations having a structure as shown in FIG. The child is disclosed. In this ultrasonic transducer, two elastic discs 2 are arranged on the outer periphery of a rod-shaped elastic body 1, and a piezoelectric disc (piezoelectric element) 3 is attached to each of these elastic discs 2. As shown in FIG. 8, the piezoelectric disk 3 is divided into four equal parts and polarized, and the elastic disk 2 is in-plane.
It is driven at a frequency that causes asymmetric vibration of.

FIGS. 8A and 8B show the vibration of the elastic disk 2 due to the driving of the piezoelectric disk 3, and the broken line shows the displacement due to the vibration. In the above-mentioned conventional ultrasonic oscillator, the vibration states (a) and (b) are generated by changing the phase to excite elliptical vibration on the outer circumference of the elastic disk 2.

[0004]

However, in the above-mentioned conventional ultrasonic transducer, the rod that holds the two elastic disks 2 is actually the elastic body 1, and as is clear from FIG. Since the support portion 4 of the elastic disc 2 that is a rod vibrates due to the asymmetric vibration of the in-plane elastic disc 2, the vibration is transmitted to the elastic body 1 and interferes with the adjacent elastic disc 2. Further, in order to prevent vibration interference, the rigidity of the rod-shaped elastic body 1 must be increased, which impedes the vibration of the elastic disc 2 and the improvement in performance cannot be expected.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an ultrasonic transducer and an ultrasonic actuator that are small in size and have a large output.

In order to solve the above problems, the present invention provides an elastic body, a fixing member for fixing the node position of the elastic body, and an elastic body for applying vibration to the antinode of the resonance bending vibration of the elastic body. The ultrasonic vibrator comprises vibration means attached to the outer periphery at intervals of 90 degrees, and the vibration means comprises an ultrasonic transducer from a laminated piezoelectric element and a load mass body fixed to the end of the piezoelectric element.

Here, the load mass body may be formed of a material having a density higher than that of the resonator.

Further, the ultrasonic transducer having the above structure is provided,
An ultrasonic actuator was configured by including a driven body that was pressed to the antinode position of the elastic body other than the arrangement of the vibrating means of the ultrasonic oscillator.

[0009]

In the ultrasonic vibrator having the above-mentioned structure, by vibrating the antinode position of the elastic body at the resonance frequency of the elastic body by the vibrating means, the load mass body provided at the end of the laminated piezoelectric element Due to the mass effect, the thickness longitudinal vibration due to the laminated piezoelectric element is vibrated by the sum of the mass of the load mass body and the laminated piezoelectric element, and the reaction force is applied to the elastic body through the laminated piezoelectric element, resulting in a strong resonance. Vibration is excited.

Further, by using a material having a high density as the material of the load mass body, the load mass body can be downsized.

Further, the ultrasonic actuator can be constructed by pressing the driven body to the vibration antinode position of the elastic body.

[0012]

[Embodiment 1] FIG. 2 is a diagram showing the principle of the present invention, and FIG. 1 is a perspective view showing an ultrasonic transducer for producing elliptical vibration using the same. (Structure) In FIG. 1, the elastic body 5 is formed of a stainless round bar, and the elastic body 5 is held and fixed by the fixing member 7 at the node 6 in the resonance bending vibration. Further, a laminated piezoelectric element 9 is adhesively fixed to the vibration antinode position 8 of the elastic body 5, and a load mass body 10 made of stainless steel is adhesively fixed to an end surface of the laminated piezoelectric element 9 to form a laminated type. The piezoelectric element 9 and the load mass body 10 constitute a vibrating means 11. In the ultrasonic transducer of the present embodiment shown in FIG. 2, in addition to the configuration of FIG. 1, two sets of vibrating means 11 are arranged on the outer circumference of the elastic body 5 at intervals of 90 degrees.

(Operation) In the ultrasonic vibrator having the above-described structure, as a basic principle, when the laminated piezoelectric element 9 is driven at the resonance bending vibration frequency of the elastic body 5 by an external power source (not shown), the laminated type The piezoelectric element 9 is excited in the stacking direction (vertical direction 12 in FIG. 1). At this time, a reaction force is applied to the laminated piezoelectric element 9 by the inertial force of the load mass body 10, and this reaction force serves as a vibrating force for the elastic body 5.

As shown in FIG. 2, the two vibrating means 11 are firmly fixed to the vibrating antinode position 8 of the elastic body 5 by adhesion with a phase of 90 degrees, and the phase of each laminated piezoelectric element 9 is fixed. By applying an appropriate voltage of the resonance bending vibration frequency of the elastic body 5 deviated by 90 degrees, the vibration antinode position 8 of the elastic body 5 elliptically vibrates. The direction of the elliptical vibration is reversed by changing the phase of the applied voltage.

(Effect) As in this embodiment, by providing the load mass body 10 at the end portion (tip portion) of the laminated piezoelectric element 9 arranged at the vibration antinode position 8 of the elastic body 5, the elastic body is formed. 5
The vibrating force applied to is increased, and the elastic body 5 is strongly excited. Here, it is important that the load mass body 10 has a large mass, and may be a solid having a high density, such as iron,
Metals with a density of 7 or more, such as brass, copper, tungsten, and lead, are desirable.

[0016]

[Embodiment 2] FIG. 3 is a perspective view showing an ultrasonic actuator of the present embodiment. The same parts as those of the first embodiment are designated by the same reference numerals as those in FIGS. (Structure) Four vibrating means 11 are firmly fixed by adhesion to the outer periphery of the vibration antinode position 8 of the resonance bending vibration in the hardened stainless steel rod-like body 5 at intervals of 90 degrees. . Further, the elastic body 5 is fixed so as to be sandwiched by the brass scissors-shaped fixing member 7 at the vibrating node position 6. The fixing member 7 has a V-shaped contact portion with the elastic body 5, and the tip of the fixing member 7 is tightened with a bolt 13 so that the elastic body 5 can be firmly fixed.

At the tip antinode position 14 at the tip of the elastic body 5, a rotor 15 made of aluminum oxalate hard alumite is pressed. The rotor 15 is rotatably fixed to a shaft 17 via a bearing 16. Both ends of shaft 17
8 is a rotor 1 by one end of a leaf spring 19 made of stainless steel.
It is urged so as to press 5 toward the elastic body 5. The other end 20 of the leaf spring 19 is fixed to the base 21. A block 22 is fixed to the base 21, and a screw hole 23 is formed in the center of the block 22. The tip 25 of the screw hole 23 has a leaf spring 1
A screw 24 for pressing and biasing 9 is screwed.

(Operation) FIGS. 4 (a) and 4 (b) correspond to FIG.
FIG. 6 is a view of the vibrating means 11 in FIG. 6 viewed from the direction of the axis 26 of the rod-shaped elastic body 5. Four vibrating means 11a, 11b, 11
c and 11d are fixed at a right angle to the elastic body 5, as shown in FIG.
4A shows a state where the vibrating means 11a and 11c are excited, and FIG. 4B shows a state where the vibrating means 11b and 11d are excited.

When the phase of the high frequency voltage applied to the vibrating means 11a and 11c is shifted by 180 degrees and applied, the laminated piezoelectric element 9 of the vibrating means 11a contracts and vibrates as shown in FIG. 4 (a). The laminated piezoelectric element 9 of the vibrating means 11c is in an expanded state. As a result, the two sets of vibrating means 11
The elastic body 5 is moved in the direction of arrow 27 by a and 11b (stacking direction)
It is vibrated with twice the force. Similarly, FIG. 4B shows an example in which the vibrating means 11b and 11d are driven, and the vibrating means 11b and 11d are vibrated with a double force in the direction of the arrow 28 (the stacking direction). By shifting the phases of the vibrations in the two directions by ± 90 degrees, the elliptical vibration is reversibly excited at the tip antinode position 14 of the elastic body 5.

Then, the rotor 15 is rotated by pressing the rotor 15 to the end antinode position 14. By pressing the leaf spring 19 with the screw 24, the rotor 15
The pressing force between the elastic body 5 and the elastic body 5 may be adjusted.

(Effect) As described above, according to this embodiment, the ultrasonic actuator can be realized with a simple structure.
Although the rotary actuator is shown in this embodiment, it is needless to say that an ultrasonic linear actuator can be formed by pressing the elastic body 5 with a driven body capable of linear operation.

[0022]

[Embodiment 3] FIG. 5 is a perspective view showing an ultrasonic actuator of the present embodiment. The same parts as those in Embodiments 1 and 2 are shown in FIGS.
Are denoted by the same reference numerals, and the description thereof will be omitted. (Structure) In the present embodiment, the load mass body 29 is fixed to the tip antinode position 14 of the ultrasonic transducer of the second embodiment in a concentric manner with the elastic body 5 by adhesion. As the material of the load mass body 29, stainless steel having a density of 7 or more, brass, copper, iron, ceramics or the like is used.

(Operation) This is the same as the second embodiment.

(Effect) The load mass body 29 provided at the end antinode 14 of the elastic body 5 has the effect of increasing the oscillator amplitude of the elastic body 5 and reducing the mechanical impedance.

(Modification) FIG. 6 shows an example in which the vibrating means 11 is fixed to the elastic body 5 by the fastening means 30, whereby the vibrating means 11 can be firmly fixed to the elastic body 5. . The fastening method is not limited to this modification, and may be fixed by utilizing the outer circumference of the fastening means 30, or may be fixed so that the opposing fastening means sandwiches the elastic body 5 integrally.

[0026]

As described above, according to the ultrasonic transducer and the ultrasonic actuator of the present invention, the load mass body is fixed to the tip of the laminated piezoelectric element whose one end is fixed to the elastic body. It is possible to excite strong vibrations, and it is possible to drive efficiently with a small size.

[Brief description of drawings]

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

FIG. 2 is a front view illustrating the principle of the ultrasonic transducer of the first embodiment.

FIG. 3 is a perspective view showing an ultrasonic actuator according to a second embodiment of the present invention.

FIG. 4 is a side view showing a main part of the second embodiment.

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

FIG. 6 is a cross-sectional view showing a modified example of the main part of the present invention.

FIG. 7 is a perspective view showing a conventional ultrasonic transducer.

8 is a front view showing a piezoelectric disc of the ultrasonic transducer shown in FIG. 7. FIG.

[Explanation of symbols]

 1,5 Elastic body 6 Nodes 7 Fixing member 8 Vibration antinode position 9 Laminated piezoelectric element 10,29 Load mass body 11 Vibrating means 14 Tip antinode position 15 Rotor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihisa Taniguchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (3)

[Claims] 1. An elastic body, a fixing member for fixing a node position of the elastic body, and a vibrating member attached to the outer periphery of the elastic body at intervals of 90 degrees in order to apply vibration to the antinode of the resonance bending vibration of the elastic body. An ultrasonic transducer comprising: a means for oscillating, wherein the vibrating means comprises a laminated piezoelectric element and a load mass body fixed to an end of the piezoelectric element. 2. The ultrasonic vibrator according to claim 1, wherein the load mass body is made of a material having a density higher than that of the resonator. 3. An ultrasonic transducer according to claim 1 or 2, further comprising: a driven body that is pressed to an antinode position of an elastic body other than the vibrating means of the ultrasonic transducer. Characteristic ultrasonic actuator.