JPH1128421A - Control method of ultrasonic generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the heat generation or the stress fatigue of a tool or the like by increasing a vibrational amplitude up to a rated value when the rate of change of a load applied on an ultrasonic vibrator transducer driven by a small vibrational amplitude during a non-load time exceeds a fixed value. SOLUTION: In a non-load state at the tip of a drill 4, the change of a current for a vibrator transducer does not occur, the output of a DC amplifier 25 is not changed as well and all of the output of a window comparator 27, a timer 30 and the like are in an L level state. Therefore, a vibrational amplitude control circuit 34 and a frequency control circuit 35 recognize a non-load mode to rotate a motor 13 at a slow speed. When a load is applied on the drill 4, the signal of the DC amplifier 25 is largely changed and the output of a differential circuit 26 is produced. When the output exceeds the setted standard level of the window comparator 27, the output of the window comparator 27 is changed to an H level and the vibrational amplitude control circuit 34 and the frequency control circuit 35 are changed to a load applied mode. As the result, the vibrational amplitude becomes a rated value, a motor 13 is rotated in a rated state to enable a usual working.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an ultrasonic generator used in an ultrasonic application apparatus such as an ultrasonic welder and an ultrasonic processing machine.

[0002]

2. Description of the Related Art Generally, ultrasonic oscillation control in this type of ultrasonic application apparatus uses means such as turning on / off the oscillation by a switch and turning on / off the oscillation using an interface. The method of controlling by means for stopping the operation is the mainstream, and in some cases, there is a method in which no special control means is provided and the oscillation is simply allowed to occur. In these cases, the increase or decrease of the vibration amplitude of the ultrasonic vibrator is usually set to a predetermined value or adjusted by an artificial operation.

[0003]

In general, when performing any operation utilizing the ultrasonic vibration of the ultrasonic vibrator, in order to further enhance the effect, it is necessary to increase the vibration amplitude of the ultrasonic vibrator. The most effective. However, if the vibration amplitude is increased, the load on the ultrasonic vibrator or the tool attached to the tip thereof will increase accordingly. As a result, there is an inconvenience that deterioration of the ultrasonic vibrator and the mounted tool due to heat generation and stress fatigue is promoted. In addition, the fact that oscillation is always the best when oscillated means that, in other words, a load is imposed on the ultrasonic vibrator and the mounted tool even when the ultrasonic wave is not in a working state.
For example, in the case of a hand-held ultrasonic cutter or ultrasonic knife, the operator cuts the object by holding the ultrasonic cutter or ultrasonic knife in his hand, but raises the vibration amplitude of the tool to the best condition. It is usual to keep. In this case, as described above, the heat generated from the ultrasonic vibrator and the attached tool is large, and in some cases, the worker himself feels hot and hinders the work. Further, when no load is applied, the stress fatigue of the tool is advanced due to such a high vibration amplitude, and there is a possibility that the cutting edge is scattered and an unexpected injury is caused.

As a countermeasure against such a situation, the oscillation may be turned on artificially each time a cut is made in the object, and the oscillation may be turned off simultaneously with the end of the work. Doing it frequently is cumbersome,
In practice, it is often impossible.

[0005] For example, a typical example is an ultrasonic drill in which various tools and the like are attached to the tip of an ultrasonic vibrator held rotatably, and processing is performed by superimposing ultrasonic vibration while rotating the ultrasonic vibrator. Consider the case of a rotary ultrasonic machining apparatus.
In such a rotary ultrasonic machining apparatus, the vibration amplitude of the tool is usually maintained at a high amplitude, and the tool is usually rotated at a high speed in order to further improve the machining performance. The control is performed by turning on / off the ultrasonic vibration. However, as the work on the workpiece becomes a continuous work, it becomes complicated to substantially stop the ultrasonic vibration, and the processing must be performed while the work is continuously vibrated. For this reason, as in the case of the above-described hand-held ultrasonic cutter and ultrasonic knife, there is a problem in that the ultrasonic transducer and the tool generate heat and promote stress fatigue. In particular, when the tool diameter is large, if the tool is brought into contact with the workpiece in a high-speed rotation state, the peripheral speed is large, so that it is easy to fall into eccentric machining due to the large peripheral speed, deterioration of machining dimensional accuracy and generation of noise due to eccentric machining And other problems. Although this point can be solved by lowering the rotation speed, the processing speed is necessarily reduced by the reduced speed. Furthermore, even at the time of no load, the high-speed rotation is always performed, so that the heat generation of the rotation drive unit is promoted,
There are also problems that noise is generated and electric energy is wasted.

Further, even when there is no load, the danger given to an operator or the like increases depending on the situation where the tool is rotating at high speed. As a countermeasure, stop the rotation when there is no load or reduce the rotation speed extremely, it is the stage to shift to machining, gradually contact the workpiece with the rotation speed reduced, and stabilize It is sufficient to shift to high-speed rotation, but the control for that is complicated, and it is difficult to apply it to a highly versatile ultrasonic processing apparatus.

Accordingly, the present invention provides a control method of an ultrasonic generator capable of preventing heat generation and stress fatigue of an ultrasonic vibrator and a tool under no load without using a special external control device. The purpose is to:

According to the present invention, it is possible to prevent heat generation and stress fatigue of the ultrasonic vibrator and the tool when no load is applied, and to perform a stable ultrasonic processing operation even in discontinuous processing. An object of the present invention is to provide a control method of an ultrasonic generator.

Further, the present invention can prevent heat generation and stress fatigue of the ultrasonic vibrator and tool under no load, and can perform stable ultrasonic processing work even in any processing environment. It is an object of the present invention to provide a control method of an ultrasonic generator which can be performed.

Another object of the present invention is to provide a control method of an ultrasonic generator capable of improving safety, suppressing noise, suppressing energy consumption, and improving machining accuracy.

[0011]

According to the first aspect of the present invention,
A change rate of a load applied to the ultrasonic vibrator driven with a small vibration amplitude for no load is detected, and when this change rate becomes larger than a certain value, the vibration amplitude for the ultrasonic vibrator is rated. Value. When a load is applied to the ultrasonic transducer directly or indirectly via a tool, etc., the state changes when no load is applied. By increasing the amplitude and automatically performing ultrasonic vibration at the rated vibration amplitude that is optimal for processing, there is no hindrance to the transition to processing work, and it is possible to keep the vibration amplitude small during standby without load, Deterioration due to heat generation and stress fatigue during standby with no load is prevented.

According to a second aspect of the present invention, a change rate of a load applied to an ultrasonic vibrator driven with a small vibration amplitude for no load is detected, and when the change rate becomes larger than a predetermined value. After increasing the vibration amplitude for the ultrasonic vibrator to the rated value, if no change in load is detected even after a certain period of time has elapsed, the vibration amplitude for the ultrasonic vibrator is set to a small value for no load. To be reduced. Therefore, in addition to the invention described in claim 1, even if the vibration amplitude is once shifted to the rated vibration amplitude, if the change in the load is not detected again within a predetermined time, it is determined that the machining has been completed, and the vibration amplitude is reduced again. Since the value is reduced to a value and the state is returned to the no-load standby state, deterioration due to heat generation and stress fatigue during the no-load standby state is prevented again. On the other hand, once the vibration amplitude is shifted to the rated vibration amplitude, the rated vibration amplitude state is maintained at least until a certain period of time elapses. The ultrasonic machining operation can be stably continued without lowering the vibration amplitude during the operation.

According to a third aspect of the present invention, a change rate of a load applied to an ultrasonic vibrator driven with a small vibration amplitude for no load is detected, and when the change rate becomes larger than a certain value. After increasing the vibration amplitude for the ultrasonic vibrator to the rated value, if the load fluctuation is not detected even after a certain period of time or more, the load consumption is detected. If so, the vibration amplitude for the ultrasonic vibrator is maintained at a rated value, and if smaller than a certain value, the vibration amplitude for the ultrasonic vibrator is reduced to a small value for no load. Therefore, in addition to the invention described in claim 1, even if the load does not change within a certain time after the shift to the rated vibration amplitude, the consumption of the load is not less than a certain value. For example, it is determined that the machining operation is continued in a high load state, and the vibration amplitude state is maintained.If the load consumption is smaller than a certain value, it is determined that the machining operation is completed. Since the vibration amplitude is reduced to a small value to return to the no-load standby state, it is possible to appropriately control the increase and decrease of the vibration amplitude without causing a malfunction even in any processing environment.

According to a fourth aspect of the present invention, in addition to the control method of the ultrasonic generator according to the first, second, or third aspect, the ultrasonic vibrator is controlled by increasing or decreasing the vibration amplitude of the ultrasonic vibrator. The operating state of the associated peripheral device is controlled. Therefore, when increasing / decreasing the vibration amplitude of the ultrasonic vibrator, the operating state of the peripheral device attached to the ultrasonic vibrator is also controlled in conjunction with the control, thereby improving safety, reducing noise and suppressing energy due to the peripheral device. Can be performed properly. Here, the peripheral device corresponds to, for example, a motor for rotating an ultrasonic vibrator, and its control corresponds to frequency control, on / off control, and the like for the motor.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. The present embodiment is applied to a control method and a device for an ultrasonic generator using an ultrasonic drill 1 as an ultrasonic application device. FIG. 1 schematically shows a configuration of an ultrasonic generator for driving the ultrasonic drill 1 and a controller thereof. In FIG. 1, an existing control portion such as an automatic tracking circuit for efficiently generating ultrasonic vibrations, a matching circuit, and the like are omitted.

First, an ultrasonic drill 1 mainly includes an ultrasonic vibrator 2 rotatably held, and a horn-type tool 3 is firmly fixed to a tip portion of the ultrasonic vibrator 2 by a screw or the like. Have been. The tip of the horn type tool 3 is formed as, for example, a drill 4. 5 is an ultrasonic transducer 2
Is a high-frequency power supply for causing the ultrasonic transducer 2 to ultrasonically vibrate, and in the present embodiment, operates as a constant voltage circuit and supplies an optimal frequency power supply to the ultrasonic transducer 2. In order to receive power supply, the high-voltage side electrode 6 drawn from the ultrasonic transducer 2 is wired to the rotating electrode 8 of the rotary connector 7, and the low-voltage side (ground side) electrode 9 drawn from the ultrasonic vibrator 2 is Wired to the rotating electrode 10 of the rotary connector 7. Here, the rotary connector 7 is rotatably positioned and fixed concentrically with the ultrasonic vibrator 2 and is rotatable synchronously with the ultrasonic vibrator 2. The high-voltage brush 11 and the low-voltage brush 12 that are components of the rotary connector 7 and that are connected to the high-frequency power supply 5 are mechanically fixed, so that the ultrasonic vibrator 2 is in a rotating state. The drive power from the high frequency power supply 5 can be stably supplied. Thus, basically, the ultrasonic vibrator 2 and the horn-type tool 3 constitute a resonator using the high-frequency power source 5 as a constant voltage source, and generate ultrasonic vibration below the resonance frequency.

Here, in the present embodiment, a motor 13 for rotating the ultrasonic vibrator 2 relative to the ultrasonic vibrator 2 is provided as a peripheral device. This motor 13
The motor gear 14 driven to rotate by the ultrasonic vibrator 2
Is arranged so as to mesh with a gear 15 fixed to a node part where vibration is zero. For the motor 13, a motor output DC power supply 16 having a variable output is connected to the wiring member 1.
They are connected via 7,18.

Next, the configuration on the control side will be described. First, a current detecting transformer 19 using a part of wiring from the high frequency power supply 5 to the ultrasonic transducer 2 side is provided, and a current detecting resistor 20 is provided between secondary windings of the current detecting transformer 19. It is connected. As described above, the high frequency power supply 5 is a constant voltage source and the ultrasonic vibrator 2 and the horn type tool 3
Is driven at the resonance frequency when the load is applied to the tip of the drill 4, the oscillator current i _a
Increases from no load. Here, when the ultrasonic transducer 2 is driven at a constant voltage, the load applied to the tip of the drill 4, that is, the work consumed at the tip of the drill 4 and the transducer current i
_{Since a} is proportional to a, _a change in the load can be known by detecting _a change in the oscillator current ia. Therefore, a value proportional to the load appears at both ends of the current detection resistor 20 as a voltage.

A high-frequency rectifier circuit 21 for performing half-wave or full-wave rectification is connected to the output side of the current detecting resistor 20, and a resistor 22 and a capacitor 2 are connected to the output side of the high-frequency rectifier circuit 21.
3 is connected, and a DC amplifier 25 and a differentiating circuit 26 are sequentially connected to the output side of the integrating circuit 24. Frequency rectifying circuit 21 and the voltage value appearing at the current detection resistor 20 and the integrating circuit 24 integrates and after rectified direct current signaling, DC amplifier 25 amplifies the integrated value, the differential circuit 26 of the oscillator current i _a This is converted into a conversion rate due to load fluctuation and output. A window comparator 27 is connected to the output side of the differentiating circuit 26. The window comparator 27 outputs an H level output when an output obtained from the differentiating circuit 26 is set in advance and indicates a rate of change equal to or more than a certain value, and outputs an L level output when the rate of change is smaller than the certain value. is there. Therefore, the detecting means 28 is constituted by the current detecting resistor 20, the high-frequency rectifier circuit 21, the integrating circuit 24, the DC amplifier 25, the differentiating circuit 26, and the window comparator 27.

On the other hand, the output side of the DC amplifier 25 is connected to a comparator 29, and a preset load level V
Compare magnitude to _L. The comparator 29, together with the high-frequency rectifier circuit 21, the integration circuit 24, and the DC amplifier 25, functions as a consumption detecting means for detecting the consumption of the load (consumption level).

A timer 30 is provided for elapse of a predetermined time T set in advance. This timer 30
The collector of the transistor 31 whose on / off is controlled in a pulsed manner is connected to the set input of the timer 30, and from the time when the transistor 31 is turned off and the potential of the collector becomes high, the timer 30 starts lapse of a predetermined time T. Start. The output of the comparator 29 and the output of the window comparator 27 are connected to the base of the transistor 31 via diodes 32 and 33 forming a wired OR. Accordingly, if the transistor 31 is turned on in a pulsed manner by the H level output of the window comparator 27 or the output of the comparator 29, the timer 30 is triggered to an active state, outputs an H level output voltage to its output side, and the transistor 31 is turned off. It functions so as to start the lapse of a certain time T starting from the point in time when it is performed.

Further, an output side of the timer 30 is connected to a vibration amplitude control circuit 34 functioning as amplitude control means and a frequency control circuit 35 functioning as peripheral device control means. The vibration amplitude control circuit 34 outputs a control signal for increasing or decreasing the vibration amplitude to the high frequency power supply 5 according to the output from the timer 30. Similarly, the frequency control circuit 35 controls the rotation frequency of the motor 13 by varying the output voltage of the motor drive DC power supply 16 for the motor 13 according to the output from the timer 30. Specifically, when the output of the timer 30 is at the H level, the vibration amplitude control circuit 34 outputs a control signal for increasing the vibration amplitude of the ultrasonic vibrator 2 to a rated value that is optimal for processing of a load. 5 and the frequency control circuit 35 controls the motor drive DC power supply 16 so as to output a drive voltage for rotating the motor 13 at a rated frequency at a high speed.
On the other hand, when the output of the timer 30 is at the L level, the vibration amplitude control circuit 34 outputs a control signal to the high frequency power supply 5 for decreasing the vibration amplitude of the ultrasonic transducer 2 to a small value for standby with no load. At the same time, the frequency control circuit 35 controls the motor drive DC power supply 16 so as to rotate the motor 13 at a low speed or output a drive voltage for stopping the rotation.

In such a configuration, control of the vibration amplitude and the like of the ultrasonic transducer 2 according to the present embodiment will be described with reference to FIG. Here, for convenience of explanation, it is assumed that the motor 13 is rotated at a low speed during no-load standby. FIG. 2 shows various states, such as a state where the tip of the drill 4 of the horn-type tool 3 firmly fixed to the tip of the ultrasonic vibrator 2 with a screw or the like is unloaded, a state where a load is applied, a state where the load fluctuates, 6 is a time chart showing the operation of each part in a proper state with the passage of time.

In FIG. 2A, V _L indicates a reference value (no-load / load determination reference value) for the load level of the comparator 29. Basically, the value integrated by the integration circuit 24 is the load level reference value. If the value is smaller than the value _VL , the comparator 29 determines that there is no load. If the value is equal to or more than the load level reference value _VL , the comparator 29 determines that a load is applied (see FIG. 2E). In FIG. 2, a section indicated by A is a state in which the tip of the drill 4 is not loaded,
The section indicated by is a state where the load applied to the drill 4 is increasing, the section indicated by C is a state where the load is actually applied to the drill 4, the section indicated by D is a state where the load is not stable and the change is drastic, E In the section indicated by, the load gradually decreases and returns to the no-load state, and in the section indicated by F, the load is applied to the tip of the drill 4 but the value is lower than the load level reference value _VL. Are respectively shown.

Firstly, in the interval A shows a state in which the leading end of the drill 4 is in the no-load, the transducer current i _a is not generated a variation does not change the output of the DC amplifier 25. This allows
The output of the differentiating circuit 25 does not change, and the output of the window comparator 27 remains at the L level. On the other hand, since the output value of the DC amplifier 25 input to the comparator 29 is also lower than the load level reference value _VL , the output of the comparator 29 becomes L level. Therefore, the transistor 31 remains off (the collector potential is maintained at the H level), the timer 30 is not set, and the output thereof remains at the L level. Therefore, the vibration amplitude control circuit 34 and the frequency control circuit 35 recognize that the apparatus is in the no-load standby mode, and rotate the motor 13 at a low speed to a driving state with low power consumption. It is controlled to be a small value for standby. That is, the oscillator current i
_a is the minimum value.

Next, in a section B where a load starts to be applied to the tip of the drill 4, the integration is performed by the integration circuit 24 and the DC amplifier 2
Since the signal amplified at 5 greatly changes as shown in FIG. 2A, the output of the differentiating circuit 26 generates an absolute value voltage of the amount of change. When the absolute value voltage exceeds the reference level of the preset change rate of the window comparator 27, the output of the window comparator 27 switches from the L level to the H level. In response, the transistor 31 is turned on in a pulsed manner, and the set input of the timer 30 is triggered to be active. As a result, the output of the timer 30 instantaneously changes to the H level. As a result, the vibration amplitude control circuit 34 and the frequency control circuit 35 recognize that the mode has shifted to the load application mode, and the vibration amplitude control circuit 34
Thus, the vibration amplitude of the ultrasonic transducer 2 is increased so as to be a rated value optimal for processing, and the frequency control circuit 35 controls the rotation of the motor 13 to a rated rotation state. As a result, a normal processing operation can be performed on the workpiece as it is. In this case, the transducer current i _a vibration amplitude increases in proportion to rises to the rated value, the load level reference value V whose value is preset in the comparator 29
If it is larger than _L , the output of the comparator 29 becomes H level.

Then, the process directly proceeds to the section C. In this section C, since the transistor 31 is maintained in the ON state, the drill 4 is supplied to the drill 4 irrespective of the set time of the timer 30 (constant time T). As long as the load is continuously applied, the motor 13 continues to rotate at the rated speed, and the vibration amplitude of the ultrasonic transducer 2 is also maintained at the rated value. As a result, the machining operation at the rated drive can be continued.

In such a section C, the load applied to the drill 4 decreases, and the value becomes the load level reference value _VL.
When the voltage becomes lower than the above, the output of the comparator 29 changes to the L level. Accordingly, the transistor 31 turns off. At this point, the timer 30 starts aging for the first time, and if the predetermined time T elapses, the output of the timer 30 becomes L level. However, the fixed time T is set to be a moderately long time in consideration of the actual situation of the machining operation and the like, and when the load is reduced instantaneously or only for a very short time, the timer 30 is still operated over time. Yes again comparator 29
Changes to the H level and the transistor 31 returns to the ON state, whereby the aging operation of the timer 30 is reset. As a result, in such a situation, the output of the timer 30 does not go to the L level, The motor 13 keeps rotating at the rated speed, and the vibration amplitude of the ultrasonic vibrator 2 is maintained at the rated value. That is, as shown in the section D, the rated operation is not interrupted even if the load is interrupted at a relatively fast cycle, and the machining operation can be performed stably.

On the other hand, if the load is not applied within the predetermined time T as shown in the section E in the state where the lapse of time has started, the output of the timer 30 changes to the L level with the lapse of the predetermined time T. Circuit 34 and frequency control circuit 3
5 recognizes that it has returned to the no-load standby mode,
Is rotated at a low speed so as to be in a driving state with low power consumption, and the ultrasonic vibrator 2 is also controlled so that the vibration amplitude becomes a small value for no-load standby. That is, the transducer current i _a becomes minimum value.

Further, even when a small load lower than the load level reference value _VL is applied to the drill 4 as shown in a section F, the load fluctuates and the window comparator 2
When the output of the switch 7 becomes H level, the transistor 31 is turned on and the timer 30 is activated. Therefore, the vibration amplitude control circuit 34 and the frequency control circuit 35 recognize that the mode has been switched to the load application mode, and instantly, the vibration amplitude control circuit 34 Thus, the vibration amplitude of the ultrasonic vibrator 2 is increased so as to have the optimum rated value for processing, and the frequency control circuit 35 controls the rotation of the frequency motor 13 to the rated rotational state. However, since the load state is originally lower than the load level reference value _VL and the output of the comparator 29 remains at the L level, the timer 30
The lapse of time starts from the point when the output on the 7-side turns to the L level again and the transistor 31 is turned off, and the constant time T
If the load does not fluctuate, the state is returned to the no-load standby state when the output of the timer 30 changes to the L level. Therefore, even if the vibration amplitude is once shifted to the rated value, if no change in the load is detected again within the fixed time T, it is determined that the machining has been completed, and the vibration amplitude is reduced to a small value again to wait for no load. Since the state is restored, it is possible to prevent deterioration due to heat generation and stress fatigue during standby with no load.

As described above, according to the present embodiment, the ultrasonic vibrator 2 is driven with a small vibration amplitude during standby with no load, and the ultrasonic vibrator 2 or the ultrasonic vibrator 2 The vibration amplitude of the ultrasonic vibrator 2 is controlled so as to automatically increase the vibration amplitude to the rated value only when a load fluctuation of a certain value or more occurs in the horn-type tool 3 mounted on the horn-type tool 3. Sometimes, it is not necessary to keep the drive state at the rated value, and it is possible to prevent heat generation of the ultrasonic vibrator 2 and stress fatigue of the horn-type tool 3 during standby with no load. In addition, since it is possible to shift to the rated drive by applying a load equal to or more than a certain value, it is possible to directly shift to the machining operation without the trouble of manually performing the on / off operation, and to improve the workability. In the present embodiment, the load application /
The rotation speed of the motor 13, which is a peripheral device, is also controlled to increase and decrease in synchronism with the increase / decrease control of the vibration amplitude of the ultrasonic vibrator 2 according to no load, so that safety is improved and unnecessary noise is suppressed. In some cases, the processing accuracy can be improved. Further, a series of control operations can be realized with a simple configuration using the control circuits 34, 35 and the like without depending on an artificial operation and without going through a complicated operation procedure represented by a computer or the like. .

[0032]

According to the first aspect of the present invention, when a load is applied to the ultrasonic vibrator directly or indirectly via a tool or the like, the state is changed when no load is applied. Then, only when the load fluctuation of the ultrasonic vibrator exceeds a certain level, the vibration amplitude is increased and the ultrasonic vibration is automatically performed at the rated vibration amplitude that is optimal for processing. In this case, the vibration amplitude can be kept small at the time of no-load standby, and deterioration due to heat generation and stress fatigue at the time of no-load standby can be prevented.

According to the second aspect of the present invention, even if the vibration amplitude is once shifted to the rated vibration amplitude, if the change in the load is not detected again within a predetermined time, it is determined that the machining has been completed, and the vibration amplitude is determined again. Since the value is reduced to a small value to return to the no-load standby state, in addition to the effect of the invention described in claim 1,
Again, it is possible to prevent deterioration due to heat generation and stress fatigue during standby with no load, and once the frequency is shifted to the rated vibration amplitude, the rated vibration amplitude state is maintained at least until a certain time elapses Therefore, during a machining operation in which an intermittent load fluctuation occurs at a relatively fast cycle, the vibration amplitude is not reduced during the machining operation, and the ultrasonic machining operation can be stably continued.

According to the third aspect of the present invention, even if the load is not changed within a certain period of time after the vibration amplitude is once shifted to the rated vibration amplitude, the consumption of the load is not less than the certain value. If there is any, it is determined that the machining operation is continuing in a high load state and the vibration amplitude state is maintained, while if the load consumption is smaller than a certain value, it is determined that the machining operation is completed. Since the vibration amplitude is reduced to a small value so as to return to the no-load standby state, in addition to the effect of the invention described in claim 1, in addition to the effect of the invention according to any of the machining environments, the vibration amplitude can be properly controlled without causing a malfunction in increasing and decreasing. can do.

According to the invention described in claim 4, according to claim 1,
In addition to the control method of the ultrasonic generator according to 2 or 3, the operation state of the peripheral device attached to the ultrasonic vibrator is controlled in conjunction with the increase / decrease control of the vibration amplitude for the ultrasonic vibrator. It is possible to appropriately improve safety, reduce noise, and suppress energy due to peripheral devices.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of each unit under various load states.

[Explanation of symbols]

 2 Ultrasonic transducer 13 Peripheral device

Claims (4)

[Claims] 1. A method of detecting a change rate of a load applied to an ultrasonic vibrator driven with a small vibration amplitude for no load, and when the change rate becomes larger than a predetermined value, the ultrasonic vibrator is detected. A method for controlling an ultrasonic generator, comprising: increasing a vibration amplitude with respect to a rated value. 2. A method for detecting a rate of change of a load applied to an ultrasonic vibrator driven with a small vibration amplitude for no load and detecting the ultrasonic vibrator when the rate of change becomes larger than a predetermined value. After increasing the vibration amplitude to the rated value, if no change in load is detected even after a certain period of time, the vibration amplitude for the ultrasonic vibrator is reduced to a small value for no load. A method for controlling an ultrasonic generator, comprising: 3. A method for detecting a change rate of a load applied to an ultrasonic vibrator driven with a small vibration amplitude for no load, and when the change rate becomes larger than a predetermined value, the ultrasonic vibrator is used. After increasing the vibration amplitude to the rated value, if no change in load is detected even after a certain period of time has elapsed, the consumption of the load is detected. Controlling the vibration amplitude for the ultrasonic vibrator to a rated value, and reducing the vibration amplitude for the ultrasonic vibrator to a small value for no load when the vibration amplitude is smaller than a fixed value. . 4. An operation state of a peripheral device associated with the ultrasonic vibrator is controlled in conjunction with a control of increasing / decreasing a vibration amplitude of the ultrasonic vibrator. A control method of the ultrasonic generator according to the above.