JPS5990672A - Ultrasonic vibrating element drive - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Technical Field The present invention relates to an ultrasonic vibrating 8-element drive system for ultrasonic vibration of ultrasonic vibrating elements for ultrasonic processing machines such as so-called ultrasonic waves and ultrasonic wave head welding machines. Related to equipment.

Prior Art In the conventional ultrasonic vibrating element drive '3A, if the machining bone installed in the ultrasonic vibrating element cracks or the machining horn is replaced, the ultrasonic vibrating element is now vibrated at a different frequency than the fundamental frequency, resulting in problems such as poor welding of the plastic workpiece, for example.

Purpose The purpose of the present invention was to solve the above-mentioned problems, and when one limb of an ultrasonic vibrating element is moved at a frequency other than the fundamental frequency, the ultrasonic vibration due to the vibration frequency of that field is An object of the present invention is to provide an ultrasonic vibrating element drive device which prevents vibration of a sonic vibrating element and automatically shifts to vibration at the fundamental frequency, thereby preventing defective welding of workpieces. .

EXAMPLE Hereinafter, an example in which the present invention is embodied in an ultrasonic processing machine will be described in detail.

As shown in FIG. 1, a branch office 2 is erected on top of the table 1, and a fixed base 3 is fixed to the bottom of the column 2. A fluid pressure cylinder 1 is fixed to the fixed base 3,
Movable frames 6 are fixed to screws 1 to 5 extending downward, and ultrasonic vibration elements 7 are held on the movable frames 6. A machining bone 8 is removably attached to the lower end of the ultrasonic vibration element 7.
The processed portion 8a of 1S@ in A is opposed to the daple 1. Further, an oscillation circuit 9 that oscillates the ultrasonic vibration element 7 is provided in stages 6.

Then, a mold 10 is placed on the table 1, two workpieces 11 made of plastic are placed in the mold 10 in a superposed manner, and the piston rod 5 of the fluid pressure cylinder 4 is moved downward. When the machining horn 8 is moved downward together with the movable frame 6, its machining portion 8a presses the machining portion 11a of the workpiece 11. In this state, when the ultrasonic vibration rF) element 7 is vibrated by the oscillation circuit 9 and the ultrasonic vibration is applied from the processing part 8a to one workpiece, both waves cause the processing part 11a of the workpiece 11 to be welded. be done. After the machining is completed, the machining horn 8 is moved upward by the fluid pressure cylinder 1, and the workpiece 11 is placed on the table 1.
− is removed from

Next, the electronic circuit of the ultrasonic processing machine of this embodiment will be explained with reference to FIG. Ultrasonic vibration element 7 LJ driving element 7a
The detection element 7b and the like are connected to each other, and the oscillation circuit 9 oscillates. Regarding the oscillation circuit 9, the actual vibration frequency f of the ultrasonic vibration element 7 is detected from the detection element 7b.
An electrical high frequency signal SG1 is output, and the high frequency signal SG1 is input to the feedback circuit 12. The feedback circuit 1
2 is a knee sensor 14 whose one end is connected to the detection element 71+ of the ultrasonic vibration element 7 and whose other end is grounded via a resistor 13, its resistor 13, and the resistor 1. The transformer 15 has a primary terminal connected in parallel with the transformer 15, and the secondary terminal of the transformer 15 is connected to the output terminal of the feedback circuit 12. A feedback signal S G 2 tJ output from the output terminal of the feedback circuit 12 is input to the attenuation circuit 16 . The depletion circuit 16 has three resistors R1, I'?
2. R3 are connected in series, and are connected in parallel to the secondary terminal of transformer '15.

An analog and log switch 17 is connected in parallel to both ends of the resistor R2, and a damping circuit 1G is connected to the resistor R1 and R2.
The output signal @SG3 is output. A output signal S G
3 is amplified by a variable amplification amplifier circuit 18 and a power amplifier circuit 19, and high frequency power is supplied from one of the power amplifier circuits to the driving element 7a of the ultrasonic vibration element 7. and,
Attenuation circuit 16. Variable amplification amplifier circuit 18. The power supply circuit 20 is constituted by one power amplifier circuit.

This oscillation circuit 9 has a voltage amplification factor of 0. It oscillates when the voltage returns.

The high frequency signal S01 from the detection element 71) of the ultrasonic vibration element 7 is input to the detection rectifier circuit 21, which converts the high frequency signal tU S G 1 into a variable DC voltage VD proportional to the voltage (1r1). The variable DC power supply 22 has a power supply voltage vC (=J~), and an output voltage vO controlled by the DC voltage VD.
is applied to the variable amplification amplifier circuit 18. Output type E of A
' VO becomes a lower value as the DC voltage VD becomes higher, and becomes higher as the DC voltage VD becomes lower. The amplification factor of the variable amplification amplifier circuit 18 is proportional to its output type ffVO. Therefore, -( , as the vibration frequency of the ultrasonic vibration element 7 decreases, the voltage value of the high-frequency signal SGI decreases, the DC voltage VD decreases, and the output voltage vO increases.
As a result, the amplification factor of the variable amplification amplification circuit 18 is increased, and a human-like high-frequency horn is supplied to the driving element 7a of the ultrasonic vibration element 7. Therefore, the ultrasonic vibration element 7 vibrates at a constant frequency, and the voltage value of the high frequency signal SG1 also remains constant. Conversely, when the vibration frequency f of the ultrasonic vibration element 7 becomes high, the same control is performed, and as a result, the JfI sonic vibration element 7 is vibrated at a constant vibration frequency, and the voltage of the high-frequency signal SG1 also increases. It becomes constant.

However, the ultrasonic vibration element 7 includes frequencies other than the Sodemoto frequency fo. Frequencies other than this fundamental frequency fO include harmonics and parasitic vibrations caused by the oscillation circuit 9, etc., but the ultrasonic vibration element 7
The so-called spurious characteristic with respect to the frequency of
I yelled that I was going to put it away and put it away. In such a state, the detection rectifier circuit 21 as described above. Variable DC power supply 2
2. Depending on the variable amplification amplifier circuit 18, it is no longer possible to keep the vibration frequency f of the ultrasonic transducer 7 constant.

In this invention, the oscillation circuit 9 is provided with a circuit configuration as described below. An electrical signal at the vibration frequency of the ultrasonic vibration element 7 is output from the connection point between the resistor 13 and the capacitor +j14 of the feedback circuit 12.
3, the frequency detecting device 23 applies a self-current voltage Vf proportional to the oscillating frequency fNl to the determining means 24. The slightly higher frequency f() is proportional to Δf.
A reference voltage generator 25 outputs a DC voltage VH proportional to a frequency slightly lower than the fundamental frequency rO, a DC voltage v proportional to a frequency [0-△[, and a DC voltage Vf and a DC voltage V1-.
A comparator 26 in which 1 and 1 are respectively input to two input terminals.
A comparator 27 to which DC voltage Vf and DC voltage VL are respectively input to two input terminals, and both comparators 26 .
It consists of an OR circuit 28 in which 27 output terminals are respectively connected to two input terminals.

The comparator 26 outputs logic 1 when the DC voltage vr becomes higher than the DC voltage V + i J:, that is, when the vibration frequency 113 of the ultrasonic vibration element 7 becomes higher than the fundamental frequency [Δf number than O]. The comparator 27 outputs an output signal of DC voltage V
When [ becomes lower than the DC voltage V, Tl, that is, the vibration frequency f of the ultrasonic vibrating cord 7 is Δf than the fundamental frequency rO (When J becomes lower, an output signal of logic 1 is output. When either or both of the outputs of the comparators 26 and 27 becomes logic 1, the OR circuit 28 outputs logic J,
! I! 1 discrimination signal SG/1 is output. The determination signal SG4 of A is sent to the alarm display means 30 via the switch 29.
Alternatively, it is input to the analog switch drive circuit 31. The alarm display means 30 is a light emitting diode Δ that generates alarm No. 13.
-Do.

It consists of an alarm display element drive circuit 33 that drives an alarm element 32 such as an alarm element 32 such as a speaker. If the actual frequency f of the ultrasonic vibrating cord 7 is not within the range of fO±△f, a discrimination signal SG4 of logic 1 is applied from the discrimination means 24 to the alarm display element drive circuit 33. , alarm element 32h) generates an alarm signal such as light or sound.

Further, when the switch 29 is turned to the analog switch drive circuit 31 side, the discrimination signal SG4 of logic 1 is output from the discrimination means 24, and the analog switch drive circuit 31
is activated, and its analog switch drive circuit 31 turns on the analog switch 17 of the attenuation circuit 16. The reduction 6592 of the attenuation circuit 16 is rR1/(R14-R2-1
-R3), but when the analog switch 17 is turned on, it becomes R17/(F?, 1'+R3). Therefore, when the up-go switch 17 is turned on, the attenuation rate of the attenuation circuit 16 becomes larger, and the overall voltage gain of the oscillation circuit 9 decreases. Therefore, even if the peak value of the spurious characteristic is equalized at a frequency close to the fundamental frequency [0, the peak value under normal conditions is lower than the peak value of the fundamental frequency fO,
It becomes difficult to oscillate at frequencies other than that, and oscillates at a fundamental frequency of 10. Eventually, the DC voltage V output from the frequency detection device 23 falls within the value range of the DC voltage VL-V1 output from the reference voltage generator 25,
From the determination means 24, argument 1! I! A signal of 0 is output.

Therefore, the analog switch drive circuit 31 does not operate, and the analog switch 17 is turned off. Then, the total voltage sum (q) of the oscillation circuit returns to its original value, and the ultrasonic transducer element 7 is vibrated at the fundamental frequency fO as in A.

The above-mentioned IFc detection rectifier circuit 21. ηA circuit consisting of an AC/DC power source 22, etc. is configured to maintain the fundamental frequency fO of the ultrasonic transducer 7 when the value of 0 deviates for some reason.
This is a circuit to keep the value constant.

On the other hand, frequency detection device 231 discrimination means 24° alarm display means 30. Analog switch drive circuit 31, analog switch 17. The circuit constituted by the attenuation circuit 16 and the like is a circuit that prevents the ultrasonic vibration element 7 from being oscillated by frequencies due to harmonic components other than the fundamental frequency fO, and its purpose is to serve this purpose.

A3, the frequency detection device 23 is a Schmitt circuit that converts the high frequency signal SG1 of the vibration frequency r into a pulse No. 13 of that frequency. The discriminating means 24 may be configured to directly measure the frequency f or period h1 and output the discriminating signal @SG4.

Effects As described in detail above, this invention number includes a frequency detection device 23 that detects the electricity 1g Vf which is proportional to the frequency f of the high frequency signal SG1 output from the detection element 7b of the ultrasonic vibration element 7. A determining means 24 determines whether the electric signal Vf detected by the detecting device 23 matches the predetermined frequency fO or not, and the determining means 24 determines whether the electric signal Vf detected by the detecting device 23 matches the predetermined frequency fO. By providing means for reducing the high frequency power supplied from the power supply circuit 2o to the driving element 7a in response to the result of the determination, if it is determined that the frequency does not match the frequency fO, When replacing with a new machining horn, etc., the fundamental frequency fo of the ultrasonic vibrating element 7 may be different.
Even if the ultrasonic vibration element 7 is about to be vibrated, it is automatically vibrated at the fundamental frequency fO, thereby eliminating welding defects on the workpiece.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention in an ultrasonic processing machine, with FIG. 1 being a side view and FIG. 2 being a circuit diagram.

Claims (1)

[Claims] 1. An ultrasonic vibration element (7) comprising a driving element (7a) and a detection element (7b); a power supply circuit (20) for supplying high-frequency power; and the ultrasonic vibration element (7) in the power supply circuit (20).
The high frequency signal (SG
In the ultrasonic vibrating element drive device including a feedback circuit (12) that provides positive feedback of I), an electric signal (V The frequency detection station (23) that detects [) and the electrical signal (Vf) detected by the frequency detection device (23) are predetermined.
The detected frequency (r) is determined by the determining means (24) for determining whether or not the detected frequency (r) matches the predetermined frequency (2/I).
0) If it is determined that they do not match, the driving element r-(7) is supplied from the power supply circuit (20) in response to the determination result of
An ultrasonic vibrating element driving device comprising: (a) means for reducing high frequency mino J supplied to the ultrasonic vibrating element drive device. 2. The power supply circuit (20> is connected to the detection element (7b)
) is an attenuation circuit (
16), and the means for reducing the high frequency electric horn includes a drive circuit (31) for driving the analog switch (17). Vibration element drive device.