JPH07132368A - Method and device for automatically following ultrasonic oscillator - Google Patents

Abstract

PURPOSE:To precisely and automatically follow an oscillator against a resonance frequency of an ultrasonic vibration system which changes corresponding to the temperature's change. CONSTITUTION:An automatic following starting point of a resonance frequency corresponding to the temperature's changing amount and its change is decided against the resonance frequency of the ultrasonic vibration system 2 which changes corresponding to the temperature's change. A temperature sensor 8 to detect the temperature change, and an arithmetic unit 9 to calculate the automatic following starting point based on the detecting value of the temperature sensor 8 are installed with connecting onto the ultrasonic vibration system 2 and an automatic following oscillator 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically tracking the resonance frequency of an ultrasonic oscillator in an ultrasonic oscillator system used in a high temperature environment such as soldering using ultrasonic waves. Regarding the device.

[0002]

2. Description of the Related Art As shown in FIG. 1, an ultrasonic oscillator system has its own vibration frequency (resonance frequency) f ₀ determined according to the mechanical structure and temperature conditions. In addition to the true resonance frequency, the oscillator system includes large and small parasitic resonance frequencies a, b, c, etc. such as harmonics. Further, this frequency f ₀ changes according to the change in the length of the substance due to the change in temperature. Generally, when the temperature rises, the length of the substance such as metal increases and the elastic modulus also changes, so that the resonance frequency of the ultrasonic vibration system decreases from f ₀ at room temperature to f ₀₁ as shown in FIG. . When vibrating the such oscillators in the ultrasonic generator, constantly detects the resonance frequency f ₀ of the oscillator system to supply frequency power corresponding to the f _0, in order to continue efficiently vibrations,
A method of automatically tracking the frequency of the oscillator system to f ₀ using an automatic tracking oscillator is used. The start of the automatic tracking, the resonance for the frequency f _0, f ₀ from the time of detecting the predetermined certain frequency (tracking start frequency) f _S
The search is started for the frequency characteristics within a certain limited range _fe , and the resonance frequencies are sequentially tracked.

[0003]

However, as described above, the resonance frequency of the oscillator system changes due to the temperature rise of the oscillator system, and further, the parasitic resonance as shown in the above a to c within the automatic tracking search range. If the frequency is included, there is a problem that in actual automatic tracking, the tracking operation deviates from the true resonance frequency range at the temperature, and the automatic tracking function is impaired. The present invention aims to provide an automatic tracking method and apparatus for an ultrasonic oscillator that solves these problems.

[0004]

The automatic tracking method of the present invention for solving the above-mentioned problems is such that when the tracking start frequency is a predetermined frequency with respect to the vibration of the vibrator 1 in the ultrasonic vibrator system 2, In the method of automatically tracking the vibration of the oscillator system 2 to the resonance frequency by starting the tracking to the frequency characteristic of the oscillator system 2 by the automatic tracking oscillator 6, the temperature of the oscillator system 2 is detected. The resonance frequency of the oscillator system 2 and the tracking start frequency corresponding to the temperature point are determined. The apparatus of the present invention also vibrates the transducer 1 of the ultrasonic transducer system 2 to start tracking to the frequency characteristic of the transducer system 2 at a predetermined tracking start frequency time point to start the transducer system. A temperature sensor 8 for detecting the temperature of the ultrasonic oscillator system 2 and an automatic tracking oscillator 6 for automatically tracking the vibration of the ultrasonic oscillator 2 at the resonance frequency are connected to the ultrasonic oscillator system 2. It is characterized in that a calculator 9 is provided for calculating and setting the tracking start frequency of the automatic tracking oscillator 6 based on the detected value of the sensor 8 and the resonance frequency of the oscillator system 2 corresponding to the temperature at the time of detection.

[0005]

In the method of the present invention, standard temperature (normal temperature)
When the vibration frequency characteristic (resonance frequency) of the ultrasonic transducer system 2 provided under the section changes with the temperature change of the transducer system 2, the automatic change is made in response to the change of the frequency characteristic according to the temperature change. The tracking start frequency of tracking is determined, and the ultrasonic vibration most suitable for the changing temperature is given. As a result, there is no energy loss and there is no influence of parasitic frequencies other than the resonance frequency. Further, in the device of the present invention, the vibration characteristics given to the vibrator 1 of the vibrator system 2 are calculated by the calculator 9 using the change temperature of the vibrator system 2 detected by the temperature sensor 8 and the resonance frequency corresponding to the change temperature. The starting frequency of the automatic tracking is determined by the value obtained by the above, and the automatic tracking oscillator 6 performs the automatic tracking corresponding to the temperature change.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment shown in FIG.
Shows a configuration diagram of the device of the present invention, in which a vibrator chip 4 is attached via a horn 3 to the tip of an ultrasonic vibrator system 2 having a vibrator 1 such as a piezoelectric element (electrostrictive element). Child 1
An automatic tracking oscillator 6 is connected to the oscillator 1 and supplies amplified ultrasonic vibration power to the vibrator 1 to generate ultrasonic vibration. The oscillator 6 receives, for example, feedback of an oscillating current from the oscillator 1 and amplifies the feedback to oscillate the oscillator 6 to automatically oscillate the oscillator 6.
(Not shown), and the oscillator 6 starts tracking to the resonance frequency characteristic when the frequency of the vibrator 1 reaches the automatic tracking start frequency f _S for the resonance frequency f _{0 when the} frequency corresponds to the example of FIG. 1. The conventional ultrasonic vibrating device is configured by the automatic tracking function that automatically tracks the information.

On the other hand, in this embodiment, the oscillator system 2 is used.
A temperature sensor 8 composed of a thermocouple is attached to the temperature sensor 8, and the temperature sensor 8 serves as a mechanism for detecting a temperature change of the vibrator system 2. The temperature sensor 8 is an arithmetic unit (circuit)
9 and the arithmetic unit 9 is connected to the automatic tracking oscillator 6
It is connected to the.

Next, the automatic tracking method by the above-mentioned device will be described. The arithmetic unit 9 uses the temperature detection signal from the temperature sensor 8 to determine the standard temperature (normal temperature) of the ultrasonic transducer system 2.
Temperature difference from T ₀ to rising temperature T ₁ (T ₁ −T ₀ ).
And the change in resonance frequency corresponding to the temperature difference (f ₀ −f
₀₁ ) is calculated, and the automatic tracking start point f _ts at the temperature rise time T _s is calculated from the tracking start point f _t0 at the room temperature T ₀ . These calculations are performed by the following equations, for example. f _ts = f _t0 {(f ₀₀ −f ₀₁ ) / (T ₁ −
T ₀ )} (T _s −T ₀ ) For example, the resonance frequency f ₀₀ when the room temperature T ₀ was 20 ° C. was experimentally 19.5 KHZ, but the resonance temperature f ₁ resonated at 220 ° C. Assuming that the frequency f ₀₁ changes to 18.5 KHZ, the tracking start point at normal temperature f _ts is set as f _{t0 at} room temperature, and the tracking start point f _ts at the time of temperature increase is obtained by the above equation as f _ts = f _t0 −900. _When the value of _ts is set in the automatic tracking oscillator 6, automatic tracking can be performed with respect to the true resonance frequency f _0s of the oscillator system 2 at the increased tracking start temperature T _s .

[0009]

According to the method and apparatus of the present invention configured as described above, when the temperature of the ultrasonic oscillator system changes during operation, the true resonance frequency of the oscillator system corresponding to the temperature change. However, since automatic tracking is always performed from an appropriate tracking start point, even if a parasitic frequency is included in the resonance frequency characteristic, accurate automatic tracking to the resonance frequency is performed, and the vibration energy of the oscillator system is There are advantages that can be used most effectively.

[Brief description of drawings]

FIG. 1 is a diagram showing a resonance frequency of an ultrasonic transducer system.

FIG. 2 is a diagram similarly showing a change state of the resonance frequency according to a temperature change of the oscillator system.

FIG. 3 is an explanatory diagram of a configuration of an apparatus of the present invention.

FIG. 4 is a diagram showing a state of automatic tracking when the temperature of a vibrator system using the apparatus of the present invention changes.

[Explanation of symbols]

1 Ultrasonic Transducer 2 Ultrasonic Transducer System 3 Horn 4 Transducer Chip 6 Automatic Tracking Oscillator 8 Temperature Sensor 9 Computing Machine (Circuit) f ₀ Resonant Frequency of Oscillator System f ₀₀ Resonant Frequency of Oscillator System at _Room Temperature f ₀₁ Resonant frequency of oscillator system at temperature rise f _0s Resonant frequency of oscillator system at start of track f _t0 Tracking start frequency at normal temperature f _ts Tracking start frequency T ₀ Room temperature (standard temperature) T ₁ Temperature at temperature increase T _s Tracking start temperature

Claims (2)

[Claims] 1. When the vibration of the transducer (1) in the ultrasonic transducer system (2) is at a predetermined tracking start frequency, the frequency characteristic of the transducer system (2) is automatically tracked. In the method of automatically tracking the vibration of the oscillator system (2) to the resonance frequency by starting with the oscillator (6), the temperature of the oscillator system (2) is detected and the time point corresponding to the temperature is detected. An automatic tracking method for an ultrasonic oscillator for determining a resonance frequency of a vibrator system (2) and the tracking start frequency. 2. An oscillator (1) of an ultrasonic oscillator system (2) is vibrated to start tracking to a frequency characteristic of the oscillator system (2) at a predetermined tracking start frequency point. An automatic tracking oscillator (6) for automatically tracking the vibration of the oscillator system (2) to its resonance frequency is connected to the ultrasonic oscillator system (2). The tracking start of the automatic tracking oscillator (6) is started by the temperature sensor (8) for detecting the temperature, the detected value of the temperature sensor (8) and the resonance frequency of the oscillator system (2) corresponding to the temperature at the time of detection. An automatic tracking device for an ultrasonic oscillator, comprising: a calculator (9) for calculating and setting a frequency.