JPH0331420Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is an ultrasonic device that has been treated with voltage resistance to prevent dielectric breakdown caused by the electric charge and to allow safe work, especially when applying ultrasonic vibrations to an electrically charged object. It concerns a sound wave vibrator.

Conventionally, when applying ultrasonic vibrations to perform ultrasonic processing on electrically charged objects, such as drilling holes,
By simply insulating between the magnetostrictive vibrator used as the ultrasonic drive source and the drive winding, electric charges are not influenced by the oscillator that drives the magnetostrictive vibrator, and danger to the operator's body is also prevented. Was.

However, in this method, the value of electric charge becomes high, and in practice, dielectric breakdown occurs at about 1 KV, so there are restrictions on use, and it is desirable to be able to use it safely even under conditions of even higher electric charges.

This invention was made in view of these points,
In the commonly used type of ultrasonic transducer, the vibration system is constructed by combining in series a "vibrator", a "cone", and a "horn" whose respective resonance frequencies are set to be the same. , in which a part of the cone is replaced with ceramic without changing the resonance frequency, and will be described in detail below with reference to examples.

FIG. 1A is a diagram showing the state when ultrasonic vibration is applied to the charged object 1 to be vibrated, and FIG. 1B
1A is a diagram showing the vibration velocity distribution of each part during the operation of FIG. 1A, and FIG. 2 is a diagram showing the shape of the insulating ceramic 4 shown in FIG. 1A.

In the figure, the ultrasonic vibrator is integrally constructed of a horn 2 made of metal such as stainless steel, a cone 3 made of the same metal, an insulating ceramic 4, and a vibrator 5 made of magnetostrictive material. The ceramic 4 is bonded to the cone 3 and the vibrator 5 with adhesive. The cone 3 is for amplifying the vibration of the end face of the vibrator 5 and transmitting it to the horn 2, and this amplitude ratio is proportional to the approximate area ratio of the thick end face (slanted part) and the narrow end face of the cone 3. .

Here, as the ceramic material used for the insulating ceramic 4, alumina, silicon nitride, etc., which have high tensile strength and can withstand vibration stress, are used. Enter it and decide accordingly.

The shape should be larger than the outer diameter of the cone 3 and the vibrator 5 in order to increase the creepage distance, considering that the dielectric strength is determined by the dielectric breakdown of the outer periphery rather than the dielectric breakdown inside the insulator itself. Ivy large diameter part 1
1 (as shown in Figure 2). In other words, the dielectric strength voltage of alumina, which is an insulator, is 15 KV/mm, so if the thickness l is 10 mm, the voltage will be 150 KV. however,
Since the dielectric strength voltage of air is lower than this, dielectric breakdown at the outer periphery can be prevented by increasing the creepage distance of the insulator to increase the dielectric strength voltage. By doing so, it is possible to prevent the charge from affecting the vibrator 5 and the like. In addition, a small-diameter protrusion 12 (shown in FIG. 2) is formed on the bottom surface, and when the cone 3 and the insulating ceramic 4 are joined, the protrusion 12 is inserted into the recess 13 provided in the cone 3.
2 is press-fitted and adhered, and is configured to prevent adhesive peeling due to internal stress generated on the joint surface.

On the other hand, since no internal stress is generated at the bonding surface between the insulating ceramic 4 and the vibrator 5, sufficient adhesive strength can be obtained even if the bonding surface remains flat without any special consideration. Note that the insulating ceramic 4 is the cone 3.
Since it forms a part of the horn 3 and the vibrator 5, the resonant frequency when both are combined is
The dimensions of both are determined based on physical constants so that they match the resonance frequency of.

Also, the periphery 3 of each end face end where the cone 3, the vibrator 5, and the insulating ceramic 4 are joined.
0 and 50 are finished with a small diameter R cut off, so the dielectric strength can be kept stable. That is, if the edges of the metal body consisting of the cone 3 and the vibrator 5, which face each other with the insulating ceramic 4 in between, have angular edges, discharge is likely to occur and dielectric breakdown will occur below a predetermined withstand voltage. By forming this, it is possible to prevent discharge from occurring.

Further, if the insulation treatment section 14 including the cone 3, the insulating ceramic 4, and the vibrator 5 is covered with a silicon compound, an even more insulating effect can be obtained.

Although not directly related to the present invention, 6 is a fixed flange provided at the vibration node position of the cone 3, 7 is an insulating case, 8 is a lead wire of the drive winding of the vibrator 5, and 9
is a connector, and when the output cord of an oscillator (not shown) is connected to this connector 9 and the ultrasonic transducer is driven, the tip of the horn 2 vibrates as shown by the arrow, and this vibration is caused by the charged vibration. applied to object 1. Further, 10 is a discharge mechanism, and when the tip of the horn is separated from the charged object, the horn 2 and the cone 3
It discharges the electric charge that has withstood.

As described above, in the present invention, the resonant frequency of the horn 2 and the vibrator 5 is reduced by integrally providing the insulating ceramic 4 having the distance necessary for a predetermined dielectric strength voltage to the cone 3 which is a part of the vibration system. There's nothing to change. Moreover, the outer diameter of the insulating ceramic 4 is made larger than the outer diameter of the cone 3 and the vibrator 5,
Since the periphery of the joint end surface with the insulating ceramic 4 is ground down with a small diameter R, discharge can be released and dielectric breakdown of the outer periphery of the insulator can be prevented. Therefore,
The influence of electric charges on the vibrator 5 etc. can be eliminated,
Voltage resistance effects can also be obtained. Practical test results show 0~
It was confirmed that it can be used in a range of about 50KV.

[Brief explanation of drawings]

FIG. 1A is a diagram showing the state when ultrasonic vibration is applied to the charged object 1 to be vibrated, and FIG. 1B
1A is a diagram showing the vibration velocity distribution of each part during the operation of FIG. 1A, and FIG. 2 is a diagram showing the shape of the insulating ceramic 4 shown in FIG. 1A. 1... Charge-resistant vibrating object, 2... Horn, 3...
... Cone, 4 ... Insulating ceramic, 5 ... Vibrator, 6 ... Fixed flange, 7 ... Insulating case, 8
... Lead wire, 9 ... Connector, 10 ... Discharge mechanism, 11 ... Large diameter part, 12 ... Projection part, 13 ...
Recessed portion, 14...Insulation treatment portion.

Claims (1)

[Claims for Utility Model Registration] (1) In an ultrasonic vibrator having a structure in which a horn, a cone, and a vibrator, each having the same resonant frequency, are integrally coupled in series, the dimensions are smaller than the diameters of the cone and the vibrator. An insulating ceramic having a large diameter with an appropriate thickness and a small diameter protrusion at the center of one end face is formed as a part of the cone, and the resonant frequency of the insulating ceramic and the cone as a whole is the same as that of the horn. and the resonant frequency of the vibrator, and the protrusion is press-fitted into a recess provided in the center of the end face of the cone and fixed by adhesive,
An ultrasonic wave having a structure in which the end face of the large diameter portion and the end face of the vibrator are adhesively fixed, and the periphery of the end face of each of the cone and the vibrator to be bonded to the insulating ceramic is shaved with a small diameter R. vibrator. (2) The ultrasonic transducer according to item 1, wherein the part where the cone, the insulating ceramic, and the transducer are joined is covered with a silicone compound.