JPH07155687A - Ultrasound vibrator - Google Patents

Abstract

PURPOSE:To eliminate the trend to load any intrinsic performance due to the attempt to support an ultrasound vibrator. CONSTITUTION:A hole 16a is provided, along an axis, in a connection bolt 16 which connects both blocks 11, 15 holding piezoelectric elements 12, 14 and a fixing shaft 17 is introduced into the hole 16 leaving a clearance. When supporting an ultrasound vibrator at the tip of the fixing shaft 17, the fulcrum of the vibrator is used as a node of vibration. Thus it is possible to support the ultrasound vibrator at a point which becomes a node of vibration in any direction.

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 more particularly to a technique for supporting the ultrasonic vibrator so as not to suppress the generation of vibration.

[0002]

2. Description of the Related Art An ultrasonic vibrator has been developed which generates a combined vibration of a longitudinal vibration and a bending vibration by applying a cyclically varying voltage to a piezoelectric element. An example is shown. The structure of the ultrasonic transducer is shown in FIG.

In FIG. 5, reference numeral 51 is a rectangular parallelepiped elastic body,
A first piezoelectric body 52 for causing longitudinal vibration to the elastic body 51 is attached to one side surface thereof. Further, a second piezoelectric body 53 for causing flexural vibration to the elastic body 51 is attached to the other side surface.
By applying a voltage that fluctuates periodically to the first piezoelectric body 52, the elastic body 51 expands and contracts in the X direction in the figure, and one point 54 of the elastic body 51 vibrates as shown by x in the figure. By applying a cyclically varying voltage to the second piezoelectric body 53, the elastic body 51 bends and vibrates in the XZ plane in the figure, and the elastic body 51
One point 54 of oscillates as indicated by z in the figure. Both piezoelectric bodies 5
When a fluctuating voltage is applied to each of Nos. 2 and 53, one point 54 of the elastic body vibrates by the combined vibration of the x vibration and the z vibration. Here, by adjusting the cycle and phase of the voltage applied to each of the first piezoelectric body 52 and the second piezoelectric body 53, it becomes possible to vibrate both the longitudinal vibration and the bending vibration at the resonance frequency, and One point 54 can be largely moved in an elliptic motion as illustrated at 55 in the figure.

Reference numeral 56 in the drawing denotes a bolt for supporting the ultrasonic vibrator, and the bolt 56 is provided at a node of vibration generated in the elastic body 51. When the elastic body 51 is supported by the support bolt 56 at the node of vibration, (E) to (H) in FIG.
As shown in FIG. 5, the elliptic motion indicated by 55 in the figure can be obtained as intended without the supporting point affecting the occurrence of vibration.

[0005]

With this structure, no particular problem occurs as long as the vibration is limited to the XZ plane. However, if the vibration surface of the bending vibration can be switched by this structure, the following problems occur. For example, in FIG. 5, the first piezoelectric body 52 causes bending vibration and the second piezoelectric body 5
When used in such a manner that 3 causes longitudinal vibration, the elastic body 51 vibrates in the XY plane.

FIG. 4 shows vibrations in the XY plane, and vibrations (A) .fwdarw. (B) .fwdarw. (C) .fwdarw. (D) .fwdarw. (A) .fwdarw. Should occur. In this case, the support bolt 56 is clearly XY
I try to swing around in the plane. However, since the support bolts 56 are actually strongly supported, the vibrations in the XY plane do not end up as shown in (E) to (H) of FIG. 4, but to the vibrations shown in (A) to (D). Try to cause. However, for the following reasons:
Actually, the vibration of (A) to (D) does not occur.

If both sides are supported by the support bolts 56, it is expected that the vibrations shown in FIGS. 4 (A) to 4 (D) will occur, but in that case, the resonance frequency also shifts and a resonance phenomenon is obtained. I will not be able to. So actually (A)
The vibration of (D) does not occur. Therefore, if the vibration is used in the XY plane, the vibration of one point 54 of the elastic body 51 becomes irregular and small. As described above, according to the conventional support structure, an ultrasonic transducer that is expected to vibrate in various planes even though it is good for vibration in one plane is inconvenient for vibration in another plane. Cannot be favorably supported. A first object of the present invention is to realize a support structure capable of generating a uniform vibration phenomenon regardless of the vibration surface. Moreover, it is intended to realize a support structure capable of constantly generating a resonance phenomenon regardless of the vibrating surface.

[0008]

An ultrasonic vibrator according to a first aspect of the present invention generates a combined vibration of a longitudinal vibration and a bending vibration by applying a cyclically varying voltage to a piezoelectric element. It is related to ultrasonic transducers, the vibration surface of bending vibration can be switched, and it is supported at a point that it is a node of compound vibration in common regardless of the vibration surface of bending vibration. It is characterized by

The ultrasonic transducer according to the second aspect is
The present invention relates to an ultrasonic transducer in which a ring-shaped piezoelectric element is sandwiched between a pair of blocks, and the two blocks are connected by a connecting rod. The connecting rod is provided with a hole along the axis. The fixing shaft, which is located with a clearance from the inner wall of the hole, is inserted into the hole, and the insertion end of the fixing shaft is fixed to the ultrasonic transducer. In this case, it is extremely preferable that the fixing shaft is fixed to the ultrasonic oscillator at the vibration node of the ultrasonic oscillator.

[0010]

According to the first aspect of the present invention, the vibration is stable regardless of the direction, because the vibration is not supported by any direction because it is always supported at the point of the node of vibration regardless of the vibration surface. Vibration is obtained. Further, according to the second aspect, since the vibrator is supported symmetrically with respect to the central axis, anisotropy does not occur in the vibration, and uniform vibration can be obtained regardless of the direction. In particular, if it is supported by the vibration node, the characteristic considering the ultrasonic transducer alone can be obtained even in a supported state, and stable resonance can be generated.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 11 and 15 are metal blocks having a substantially cylindrical shape, and in a state where a piezoelectric element (in this case, two layers of piezoelectric elements 12 and 14) is sandwiched between the two blocks 11 and 15, Are connected by connecting bolts 16. A divided electrode 13 divided into four pieces is sandwiched between the two layers of piezoelectric elements 12 and 14, as shown in FIG. The piezoelectric elements 12 and 14 and the divided electrode 13 have a ring shape, and the connecting bolt 16 passes through this inner hole with a clearance. That is, the piezoelectric elements 12, 14
The divided electrode 13 is insulated from the connecting bolt 16. The connecting bolt 16 is threaded at both ends and is screwed into a screw hole provided on the axis of each of the blocks 11 and 15. Both the blocks 11 and 15 and the metal connecting bolt 16 are grounded and used.

A high frequency voltage can be selectively applied to the divided electrodes 13a to 13d. When a high frequency voltage is applied to the electrode 13a in FIG. 2, co-vibration shown in FIGS. It occurs within the plane shown in. Resonance is horn 11 of block 11
Amplified by a, the tip of the horn 11a makes a large elliptical motion in the XY plane (18). When a high frequency voltage is applied to the electrode 13c in FIG. 2, resonance shown in FIG. 4 (H) → (E) occurs in the plane indicated by Y in FIG. In this case, the tip of the horn 11a is X
A large elliptical motion is made in the Y plane, but its direction is opposite to the elliptic motion shown in 18.

When a high frequency voltage is applied to the electrode 13b in FIG. 2, resonance shown in FIGS. 4 (E) → (H) occurs in the plane indicated by Z in FIG. In this case, the tip of the horn 11a makes a large elliptical motion in the XZ plane. This direction is orthogonal to the elliptic motion in FIG. When a high frequency voltage is applied to the electrode 13d in FIG. 2, an elliptic motion in the opposite direction occurs in the XZ plane.

In this way, this ultrasonic oscillator causes elliptical vibration which is a combination of longitudinal vibration and bending vibration, and the bending vibration surface at that time can be switched. Also in the case of the vibration, the point 17a in the drawing is a node of the vibration. That is, the vibrations shown by (E) to (H) in FIG. 4 are taken on any surface, and the node of vibration shown by 56 in FIG. 4 corresponds to the point 17a in FIG.

In the structure of FIG. 1, the connecting bolt 16 is provided with a hole 16a along its axis. The fixing shaft 17 is inserted into the hole 16a. The fixing shaft 17 has a clearance CL with the inner wall of the hole 16a.
It is located with. Insertion end 1 of fixing shaft 17
7a has an enlarged diameter and is fixed to the hole 16a of the bolt 16. The tip enlarged diameter portion 17a of the fixing shaft 17 is press-fitted and fixed in the hole 16a. Instead of press-fitting, it may be bonded. Base flange 1 of fixing shaft 17
7b is fixed to the device, whereby the ultrasonic transducer is supported by the device.

Now, in the case of this embodiment, the fixing shaft 1
7 supports the ultrasonic transducer at a point 17a which is a node of vibration in common regardless of its vibrating surface.
Anisotropy does not occur in vibration, and common vibration characteristics can be obtained in all directions. Further, since it is supported by the vibration node, the physical system of vibration is not affected by the support, and a stable resonance phenomenon can be obtained.

FIG. 3 shows another embodiment. In this case, a screw is cut on the outer periphery of the enlarged diameter portion 37a of the tip of the fixing shaft 37, and this screw is screwed into the screw hole of the metal block 31. By being crushed, the ultrasonic transducer is fixed to the fixing shaft 37. Also in this case, the enlarged tip portion 37
a is located at a point that is a node of vibration in common regardless of the vibrating surface, and the same phenomenon as in FIG. 1 can be obtained. In this way, since the tips of the horns 11a and 31a can be largely moved in an elliptical plane in any plane, the object can be driven in any direction by the tips of the horns.

[0018]

According to the present invention, since the ultrasonic vibrator is supported not by the outer periphery but by the axial center portion, anisotropy may occur in the vibration when supporting the ultrasonic vibrator. To be prevented. Further, regardless of the vibrating surface, since it can be commonly supported at a point serving as a node of vibration, a resonance phenomenon can be stably generated and stable ultrasonic vibration can be obtained.

[Brief description of drawings]

FIG. 1 is a central sectional view of a first embodiment.

FIG. 2 is a plan view of a divided electrode.

FIG. 3 is a central sectional view of the second embodiment.

FIG. 4 is a diagram schematically showing the state of vibration in an enlarged manner.

FIG. 5 is a view showing a conventional support structure.

[Explanation of symbols]

 11 Blocks 12 and 14 Piezoelectric elements 13 (13a to 13d) Split electrodes 16 Connection bolts 17 Fixing shafts 17a and 37a Support points (vibration nodes)

Claims (3)

[Claims] 1. An ultrasonic vibrator for generating a combined vibration of longitudinal vibration and flexural vibration by applying a cyclically varying voltage to a piezoelectric element, the vibrating surface of the flexural vibration being switchable. Also, an ultrasonic transducer having a support point at a point that is commonly a node of compound vibration regardless of the vibration surface of the bending vibration. 2. In an ultrasonic transducer in which a ring-shaped piezoelectric element is sandwiched between a pair of blocks and both blocks are connected by a connecting rod, the connecting rod is provided with a hole along an axis. In the hole, a fixing shaft located apart from the inner wall of the hole with a clearance is inserted, and an insertion end of the fixing shaft is fixed to the ultrasonic transducer. Ultrasonic transducer. 3. The ultrasonic vibrator according to claim 2, wherein the fixing shaft is fixed to the ultrasonic vibrator at a vibration node of the ultrasonic vibrator. Child.