JPH0574435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in self-excited resonant vibration devices.

[Conventional technology]

Conventionally, this type of vibrating device was
There is one described in Publication No. 88282.

FIG. 6 is a block diagram showing the configuration of this type of conventional vibrating device. 1 is a parts conveying device such as a parts feeder, and as shown in FIG. Bowl 10 to be transported
2. A plurality of elastic bodies 103 that support this ball;
It has a vibration driver M (in this example, an electromagnet 104 and a suction plate 105) and a vibration isolating leg 106. Reference numeral 2 denotes a vibration detector, and for example, in the case of a magnetic type vibration detector, it is arranged opposite to a vibrating body such as a bowl 102 or an elastic body 103. A power amplifier 3 amplifies the power of the vibration signal v detected by the vibration detector 2 and supplies power having a positive phase with respect to the vibration signal v to the coil of the electromagnet 104. Note that this power amplifier 3 has a function of automatically adjusting the width of the current pulse flowing through the coil of the electromagnet 104.

In this vibrating device, when the bowl 102 is vibrated, the vibration detector 2 detects the generated vibration and sends out a vibration signal v, and the power amplifier 3 amplifies the power of this vibration signal to coil the electromagnet 104. Therefore, the electromagnet 104 applies an electromagnet (excitation force) proportional to the magnitude of the supplied electric power to the suction plate 105, and the bowl 102 is moved under the conditions and loads (components inside the bowl 102) specific to the transport equipment. It is vibrated at a natural frequency ω ₀ determined by external conditions such as grounding conditions.

[Problem that the invention seeks to solve]

In this way, the above-mentioned vibration device vibrates self-excited and resonates at the natural frequency ω ₀ of the vibration system, so when the natural frequency ω ₀ of the vibration system is This has the advantage of eliminating the need to adjust the frequency to the commercial frequency or its multiples by increasing or decreasing the number of elastic bodies 103, but the power amplifier 3 generates an output only after receiving the vibration signal v from the vibration detector 2. Therefore, when the bowl 102 is stationary, turn on the power switch and turn on the power amplifier 3.
Even if the power supply is connected to the component transport equipment, the component transport equipment does not vibrate, and in order to make it vibrate, it is necessary to separately provide some kind of vibrating means and apply a shock to the vibration system when generating vibration. This is particularly inconvenient when a large number of vibration devices are operated and monitored.

Further, in the conventional vibrating device described above, the electromagnet 104
Since the current supplied to the circuit is a pulsed current and the pulse width of the pulsed current is controlled to keep the vibration amplitude constant, the noise due to harmonic vibration is large, especially when the load is light. become noticeable.

This invention was made to solve the above-mentioned conventional problems, and it can be used without any special vibration excitation means.
In addition to being able to generate vibrations reliably and quickly,
It is an object of the present invention to provide a self-excited resonant vibration device that can quickly stop vibration and perform constant amplitude control without causing harmonic vibration.

[Means for solving problems]

In order to achieve the above object, in the first invention, a power amplifier that supplies power to a vibrating device is a power amplifier with a variable amplification degree, and the amplification degree is determined by a difference between a target amplitude setting device and the vibration amplitude of the vibrating device. In the second aspect of the invention, the amplification degree is further reduced by the operation stop signal to substantially eliminate the amplification effect.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 11 is an amplifier that amplifies the vibration signal v of the vibration detector 2. In FIG. Reference numeral 12 denotes a phase shift circuit section, which includes a phase shifter 13 and a phase inverter 14. This phase shifter 13 includes two first-order delay elements (integrators) 15A and 15, as shown in FIG.
B are connected in series, each integrator 15A, 15
B sends out an output with a phase delay of π to 3π/2 with respect to the input phase by adjusting the variable resistor _r1 , so the output of the phase shifter 13 has a phase delay of 0 to π with respect to the vibration signal v. A signal having a delay and a phase lead in the range of 0 to π with respect to the vibration signal v can be extracted from the phase inverter 14. When the phase non-inversion switch 16 is turned on, the phase inverter 14
A signal having a phase delay of 0 to π with respect to the vibration signal v is extracted from the vibration signal v. C is a capacitor, r ₂ ,
r ₃ , r ₄ , and r ₅ are resistances. Reference numeral 17 denotes a variable amplification power amplifier, the configuration of which will be described later.
Note that the power amplifier 17 may be provided with a step-up or step-down transformer on its output side, if necessary. 18 is a signal converter which receives the vibration signal v from the vibration detector 2 through the amplifier 11 and sends out a DC signal A having a magnitude proportional to the amplitude of the vibration signal v. 19 is a comparator, which is a target amplitude setter 2;
The DC signal A is compared with the target amplitude signal A ₀ created by the DC signal A, and the deviation signal ε thereof is supplied to the control amplifier 21. A signal a output from the control amplifier (DC amplifier in this example) 21 is supplied to the power amplifier 17 as an amplification degree control signal. Further, an operation stop signal b is supplied to the power amplifier 17 via an operation stop switch 22. This power amplifier 17
As shown in FIG. 3, the photocoupler 23 has a phototransistor Tr (its equivalent resistance is R _x ) in parallel with the feedback resistor R _f , and a control amplifier 21 is connected to the light emitting diode D of the photocoupler 23 . The amplification control signal a is supplied through the resistor _r6 . R _i is the input resistance. 24 is a photocoupler whose light emitting diode D is connected to the control power source E+
and the operation stop switch 22, and the phototransistor Tr is inserted between the control power source E ₊ and the resistor _r7 . 25 is an abnormality detector which monitors the magnitude of the output signal a of the control amplifier 21 and the amplification upper limit signal c created by the limit setter 26, and determines that c=a.
When this happens, the abnormality detection signal d is supplied to the alarm 27, and at the same time, the signal d is supplied to the power circuit breaker 28 as a power cutoff signal. 29 is a drive power supply (DC power supply),
30 is a power switch.

Next, the operation of this device will be explained.

In terms of vibration engineering, the phase of the vibration of the component conveying device 1 that vibrates in response to the excitation force of the vibration drive element M is generally delayed in the range of 0 to π, and the excitation force is adjusted to the frequency ω and the vibration of the vibrating device. When the natural frequency ω ₀ matches, it becomes π/2. When ω<ω ₀ , it is smaller than π/2, and when ω>ω ₀ , it is larger than π/2.

Now, the phase shift circuit section 12 has an output of π/
The variable resistor _r1 is adjusted so that the leading phase of the vibration detector 2 is set, and the mounting direction of the vibration detector 2 is correct, that is, the phase of the vibration signal v sent out by the vibration detector 2 and the vibration phase of the component transport device 1 are adjusted. It is assumed that these are in phase and that the component transport device 1 is vibrating. The vibration signal v is amplified by an amplifier 11 and supplied to a phase shift circuit section 12 . The phase shift circuit unit 12 sends out a signal v ₊ whose phase is advanced by π/2 with respect to the vibration signal v, and the signal v ₊ is supplied to the power amplifier 17.
The frequency of the power amplifier 17 is the natural frequency ω ₀ and the phase is π/with respect to the vibration phase of the component transport device 1.
The sinusoidal AC power, which is the leading phase of
The drive element M receives this power and operates, exerting an excitation force on the elastic body 103 and vibrating the bowl 102 of the component transport device 1. On the other hand, the comparator 19 monitors the deviation of the actual vibration amplitude A of the component transport device 1 from the target amplitude A ₀ , and the deviation ε
=A-A An amplification control signal proportional to A ₀ is supplied to the photocoupler 23 of the power amplifier 17 .
When this amplification degree control signal a flows to the light emitting diode D, a phototransistor is activated in accordance with the amount of light emitted.
Since the resistance value R _x of the Tr decreases, the power amplifier 17
The amplitude of the output AC of the power amplifier 17 is controlled so that it becomes smaller as the deviation ε becomes larger, and conversely, it becomes larger as the deviation ε becomes smaller. Amplitude A is constant amplitude controlled to ₀ .

In this way, in this embodiment, since the power supplied to the drive element M is a sinusoidal alternating current, the noise can be significantly reduced compared to the conventional case where the power is a pulsed wave.

Next, the vibration operation of the component transport device 1 will be explained with reference to the oscillograph shown in FIG.

In order to generate vibrations, the power switch 3 is turned on at time t ₀ .
0 and immediately open the switch 22. At this time, there is no vibration signal v, and the signal converter 18
When the DC signal A=0, the above deviation ε becomes A ₀ , and
The amplification control signal a becomes smaller, and the power amplifier 17
Since the degree of amplification increases, internal noise is greatly amplified in the power amplifier 17, and a noise-like output is generated from the power amplifier 17. This noise-like output causes the driver M to operate, and after a time Δt, vibrations occur in the component transport device 1.

FIG. 5 is an example of an oscillograph of a vibration phenomenon during excitation based on an experiment conducted by the present inventor, and as can be understood from this, excitation was completed in only about 0.5 seconds after the switch 22 was opened. There is.

Next, when the operation stop switch 22 is turned on while the component transport device 1 continues to vibrate, the light emitting diode D of the photocoupler 24 emits light, so the phototransistor Tr is turned on, and the control power source E+ is turned on. Since the voltage (operation stop signal b) is applied to the light emitting diode D of the photocoupler 24, the amount of light emitted increases rapidly and the photodiode Tr is turned on, and the feedback resistor Rf is almost short-circuited, so that the amplification degree G becomes almost the same. The output of the power amplifier 17 reaches the vibration signal level, and the driver M loses its excitation force due to insufficient power supply, so the vibration of the component transport device 1 immediately stops.

Therefore, according to this embodiment, the power switch 3
The operation stop switch 22 can be operated without turning 0 on or off.
Since it is possible to quickly stop and vibrate by turning on and off the parts conveying device 1, especially when operating and controlling a large number of component conveying devices 1 all at once from the operator's cab, the component conveying devices 1 can be frequently activated.・It is extremely convenient when the operation mode is stopped.

While the parts transport device 1 continues to vibrate,
Now, when abnormal vibration occurs for some reason and the amplification degree control signal a decreases abnormally and reaches the amplification degree upper limit value c, the abnormality detector 25 sends out an abnormality detection signal d. As a result, the alarm 27 is activated and the operator is notified that abnormal vibration has occurred, and at the same time the power circuit breaker 29 is opened and the power supply to the drive element M is cut off. This can ensure protection in such cases.

Also, when the amplification control signal a increases abnormally (switch 22 in FIG. 3 is off), the alarm 27
can be operated.

Further, in this embodiment, when the phase non-inversion switch 16 is turned on, a signal having a phase delay of π/2 with respect to the phase of the vibration signal v is supplied to the power amplifier 17. If the phase of the vibration signal v is opposite to the vibration phase of the component transport device 1 because the mounting direction of the device 2 is reversed (in this case, the vibration does not occur even if the power switch 30 is turned on). ), it is sufficient to simply turn on the switch 16 without having to take the trouble of changing the connection of the power supply line from the power supply amplifier 17 to the driver M.

Further, since the phase shift circuit section 12 of the above embodiment can lead its output phase in the range of 0 to π with respect to the phase of the vibration signal v, the component transport device 1 can be Not only can it be vibrated at the frequency ω ₀ , but it can also be operated with the vibration frequency shifted from the above-mentioned natural frequency, and the required stability can be easily obtained. Furthermore, since this phase shift circuit section 12 can extract a signal with an advanced phase using a delay element, it has the advantage of being resistant to noise compared to the case where a differential type circuit is used. Of course, the phase shift circuit section 12 is one transferer 1.
It may be configured with 5A.

Note that in the above embodiment, a DC amplifier is used as the control amplifier 21, but the control amplifier 21 is not limited to this, and for example, a PID amplifier may be used.

Further, although the phase non-inversion switch 16 has been described as a manual switch, for example, a switching transistor may be used, and after the power switch 30 is turned on,
If an element is provided that supplies the base current to the transistor on the condition that there is no vibration signal v after a certain period of time has elapsed, even if the vibration detector 2 is installed in the opposite direction, the phase shift circuit section 12 The output phase of the output phase can be automatically corrected.

Further, in the above embodiment, the case where the vibration driver M is an electromagnet has been described, but even if it is another vibration driver, such as a voltage actuator,
Similar effects can be obtained by implementing this invention.

In addition, although constant amplitude control is performed in the above embodiment, if it is desired to control the conveyance speed at a constant value, as shown in FIG. A second signal converter 31 for converting into a DC signal is provided, and the output F of the signal converter 31 and the output A of the signal converter 18 are combined into a multiplier 32.
The multiplied value S=F×A is multiplied by the comparator 19.
The configuration may be such that the target transport speed S ₀ is compared with the target transport speed S 0 created by the target transport speed setting unit 120 and the deviation is introduced to the control amplifier 21 .

〔Effect of the invention〕

As explained above, this invention uses a variable amplification power amplifier as a power amplifier that supplies power to a vibrating device, and has a configuration in which the amplification degree is controlled by a signal proportional to the difference between the target amplitude and the detected amplitude. In addition to being able to perform constant amplitude operation without making a lot of noise, it is also possible to quickly generate vibrations without using any special vibration excitation means, and furthermore, it is possible to quickly repeat the activation and stopping of vibrations. This can be done with a switch other than the power switch.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of this invention.
Fig. 2 is a circuit diagram of the transfer circuit section in the above embodiment, Fig. 3 is a circuit diagram of the power amplifier in the above embodiment, Fig. 4 is a block diagram of another embodiment of the present invention, and Fig. 5 is a circuit diagram of the above embodiment. FIG. 6 is a block diagram showing a conventional resonant vibration device, and FIG. 7 is a side view of a component conveying device. 1... Vibration equipment, 2... Vibration detector, 12...
Transfer circuit section, 17... variable amplification power amplifier,
18, 31...signal converter, 20...target amplitude setter, 21...control amplifier, 22...operation stop switch. 32... Multiplier, 120... Target conveyance speed setting device.

Claims (1)

[Claims] 1. A vibration detector that detects vibrations of a vibration device, a phase shift circuit unit that advances the phase of an output signal of the vibration detector, and a signal supplied from the phase shift circuit unit that amplifies the above-mentioned signal. a power amplifier with variable amplification for supplying a vibration drive element of a vibration device; a first signal converter to which the vibration signal is guided and which sends out a signal proportional to the amplitude of the vibration signal; a second signal converter that sends out a signal proportional to the frequency of the signal, a multiplier that multiplies the outputs of the first and second signal converters, a comparator that compares the output of the multiplier with a target conveyance speed; A self-excited resonant vibration device comprising a control amplifier that amplifies the output of the comparator, and the output of the control amplifier is supplied to the power amplifier as an amplification control signal. 2. A vibration detector that detects vibrations of a vibration device, a phase shift circuit unit that advances the phase of an output signal of the vibration detector, and a vibration driver of the vibration device that amplifies the signal supplied from the phase shift circuit unit. a power amplifier with variable amplification for supplying the vibration signal to the vibration signal, a signal converter to which the vibration signal is guided and outputs a signal proportional to the amplitude of the vibration signal, a comparator to compare the output of the signal converter with a target amplitude;
It has a control amplifier and an operation stop switch circuit that amplify the output of the comparator, the output of the control amplifier is supplied to the power amplifier as an amplification degree control signal, and the signal generated by the operation stop switch circuit is used to stop the amplification operation. A self-excited resonant vibration device, characterized in that the signal is supplied to the power amplifier. 3. A vibration detector that detects vibrations of a vibration device, a phase shift circuit unit that advances the phase of an output signal of the vibration detector, and a vibration driver of the vibration device that amplifies the signal supplied from the phase shift circuit unit. a first signal converter from which the vibration signal is guided and which outputs a signal proportional to the amplitude of the vibration signal; a first signal converter from which the vibration signal is guided and which outputs a signal proportional to the frequency of the vibration signal; a second signal converter that sends out a signal, a multiplier that multiplies the outputs of the first and second signal converters, a comparator that compares the output of the multiplier with a target conveyance speed, and amplifies the output of the comparator. The output of the control amplifier is supplied to the power amplifier as an amplification control signal, and the signal generated by the operation stop switch circuit is supplied to the power amplifier as an amplification stop signal. A self-excited resonant vibration device characterized by: