JPH06238236A - Vibration generator - Google Patents

Abstract

PURPOSE:To obtain a small-sized lightweight, inexpensive and efficient vibration generator simplified in circuit constitution by changing the cycle of chopping voltage to change the number of frequency of a vibration element and changing the width of chopping voltage to change the amplitude of the vibration element. CONSTITUTION:A vibration generator is equipped with an AC power supply 1, a DC power supply part 2 rectified by a diode, a chopper part 3 chopping the DC voltage of the DC power supply part 2 to output cyclical pulsating voltage of a rectangular wave, the control part 5 of the chopper part, the electromagnet 4 excited by the output of the chopper part 3 to generate attraction force, the vibration element 6 driven by the electromagnet 4 and the spring 7 supporting the vibration element 6. The cycle of chopping voltage is changed to change the number of frequency of the vibration element 6 and the width of chopping voltage is changed to change the amplitude of the vibration element 6. By this constitution, the number of frequency and amplitude of the vibration element can be changed by simple constitution and can be controlled constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Use The present invention relates to a device for generating vibration for functioning a parts feeder, a sieve, etc., and particularly, it is possible to change the frequency and amplitude and The present invention relates to a vibration generator that can be controlled to be constant. (B) Prior Art FIG. 2 is a block diagram showing the basic principle of a vibration generator which is the background of the present invention. The configuration is such that the AC power source 1 is connected to the DC power source unit 2, the DC power source unit 2 is connected to the inverter unit 8, and the inverter unit 8 is connected to the vibrating electromagnet 4 and faces the attracting surface of the electromagnet 4. The magnetic vibrating body 6 is fixed by a spring 7. Regarding the operation, the power of the AC power supply 1 is converted into DC power in the DC power source unit 2, the DC power is converted into AC power in the inverter unit 8, and the electromagnet 4 is excited by the AC power. Since the electromagnet 4 is excited by alternating current, its attractive force changes and the vibrating body 6 vibrates. With this configuration, if the output frequency of the inverter unit 8 is changed, the frequency of the vibrating body 6 changes. The output voltage waveform of the inverter unit 8 is a waveform as shown in FIG. 3, and in order to change the attractive force of the electromagnet 4, generally, in the case of the waveform of FIG. In this case, the pulse width is changed to change the suction force to change the amplitude of the vibrating body 6. (C) Problems to be solved by the invention At present, most of the vibration generators that can only adjust the amplitude are used in parts feeders and the like. However, if the frequency can be adjusted and it can be adjusted to an arbitrary frequency, it is very desirable because it helps simplify the resonance structure of the machine, etc., but the above-mentioned vibration generator is complicated in structure and large and expensive. Its spread is hindered. The present invention aims to improve this point. (D) Means and Actions for Solving the Problem The present invention is to utilize the attraction force generated by exciting the electromagnet with the rectangular wave voltage obtained by chipping the DC voltage for the vibration generation. First, the method of exciting the electromagnet of the present invention will be described. FIG. 4 is an excitation circuit diagram and FIG. 5 is an operation waveform diagram thereof. In FIG. 4, when the tipper switch 9 is turned on for a period of T1 during the time T1, the DC power source 2 excites the electromagnet 4, and the voltage and current waveforms during that time are as shown in a and b of FIG. 5, respectively. The exciting current increases in proportion to the voltage application time. Next, after T1, when the tipper switch 9 is instantly switched to the low side, a counter electromotive voltage is generated in the electromagnet 4 and an exciting current flows through the resistor 10. As for the magnitude of the counter electromotive voltage and the decreasing time of the exciting current, the smaller the resistance value of the resistor 10, the lower the counter electromotive voltage and the longer the decreasing time. Further, in this case, power loss occurs at the resistor 10. In FIG. 6, a DC power supply 2a having the same voltage as the DC power supply 2 is used instead of the resistor 10,
A diode 11 is inserted so that a current does not flow from the power source to the electromagnet 4. In this figure, when the tipper switch 9 is turned on to the side "b", the counter electromotive voltage of the electromagnet 4 becomes substantially equal to the voltage of the DC power supply 2a, and the increase and decrease times of the current become substantially equal. A waveform showing this state is shown in FIG. In FIG. 7, a is a voltage waveform of the electromagnet 4, and b is a current waveform. In this case, the electromagnetic energy of the electromagnet 4 is injected into the DC power supply 2a and no power loss occurs. In the circuit of FIG. 6, the longer the time the chewper switch 9 is on the side of a, the larger the current of the electromagnet 4, and the longer the time the chewper switch 9 repeats between a and b, the triangular wave flowing through the electromagnet 4. The current generation cycle becomes longer. The electromagnet attached to the parts feeder was excited by the triangular wave current with such a gap, but there was no problem in conveying the parts as compared with the case where it was excited by the conventional current waveform. (E) Embodiment FIG. 1 is a block diagram showing the basic principle of an embodiment of the present invention using the above-mentioned chopping method. In the figure, an AC power supply 1 is connected to a DC power supply unit 2 and converted into a DC voltage here. An electromagnet 4 is formed by periodically chopping a DC voltage at a chopper unit 3 connected to a DC power supply unit 2 at equal time intervals.
Supply to. And the control unit 5 connected to the chipper unit 3
The frequency and amplitude of the vibrating body 6 are controlled by controlling the chipping cycle and chipping time in the chipper unit 3. FIG. 8 shows an embodiment of the present invention, which will be described below.
The DC power supply unit 2 is connected to the AC power supply 1. The DC power supply unit 2 is composed of a bridge diode 70 and a capacitor 20, and converts the power from the AC power supply 1 into DC and smoothes it to obtain DC power. Transistors 30 and 31 are used as main switching elements in the chipper unit 3, and the DC positive line 100 and the negative line 1 from the DC power source unit 2 are respectively used.
01 and both terminals 102 and 103 of the electromagnet 4 are connected in a direction in which a direct current can flow. Also diode 7
1 and 72 are the positive and negative lines and the electromagnet 4, respectively.
The two terminals 102 and 103 are connected in a direction in which a DC voltage is blocked. That is, the transistors 30 and 31
And diodes 71 and 72 are alternately connected in the form of a bridge. In such a circuit the transistors 30 and 3
When 1 is simultaneously turned on by flowing a current to its base, the voltage of the chipper unit 3 is applied to the electromagnet 4 and an exciting current flows.
Next, when the base currents of the transistors 30 and 31 are simultaneously cut off and turned off, a counter electromotive voltage is generated in the electromagnet 4 and the exciting current flows back to the capacitor 20 via the diodes 71 and 72. Therefore, the transistor 30
By controlling the base currents of 31 and 31, the generation period of the current flowing to the electromagnet 4 and its value can be arbitrarily controlled. By using such a chipper unit 3, this device can control the vibration with only two main switching elements, which not only simplifies the configuration but also reduces switching power loss due to the reduced number of switching elements. Less. Next, the main transistors 71 and 7 of the chipper unit 3
The drive circuit of No. 2 will be described. The emitter of the transistor 32 is connected to the positive line 100 of the DC power supply, and its collector is connected to the base of the transistor 30. The base of transistor 32 is connected to positive line 100 by resistor 50 and to the collector of transistor 34 by resistor 51.
The collector of the transistor 33 is the collector of the transistor 31, and the emitter of the transistor 33 is the transistor 3
1 and the base of the transistor 33 are connected to the emitter of the transistor 34, respectively. When a current flows through the base of the transistor 34 in such a circuit, the transistor 34 is turned on, whereby the transistor 32 is turned on and a base current flows through the transistor 30 to turn on the transistor 30. On the other hand, the transistor 33 also turns on, a base current flows through the transistor 31, and the transistor 31 turns on. There are two main points in this circuit. One is a method of driving the two main switching transistors 30 and 31. That is, these transistors are electromagnets 4
, Which are connected separately to both terminals, and the drive circuit is not in the same potential in any line, and it depends on how a simple circuit drives this. The other is to provide an amplifier circuit in front of the main switching transistors 30 and 31 in order to reduce the output current of the control unit 5, that is, the drive current of the chipper unit 3, especially for the purpose described later. It is how to reduce the loss in. In particular, when the voltage of the DC power supply is a rectified voltage of, for example, 200 VAC or 100 VAC, it is higher than the necessary control voltage, and if a circuit is provided on the positive and negative lines, the loss becomes very large. For this reason, in FIG. 8, only one circuit, that is, the circuit of the resistor 51, which is the minimum necessary, is provided for the circuit which is still connected to the positive and negative lines of the DC power source by the Darlington connection. This minimum of one circuit includes a positive / negative switching unit and a control unit 5.
Control unit 5 so that it can be driven by one drive signal from
It is necessary to simplify the circuit of. Next, the control unit 5 will be described. First, a control power supply for operating the control unit 5 will be described. The collector of the transistor 35 for obtaining a constant voltage is connected to the positive line 1 of the DC power source with the resistor 54.
Connect to 00. Also, the base of the transistor 35 is a resistor 5
3 is connected to the positive line 100 of the DC power supply, and the Zener diode 73 is connected to the negative line 101 of the DC power supply. This circuit is one of series regulators, and the voltage of the DC power supply is dropped by the resistor 54 and the transistor 35, and a constant voltage corresponding to the voltage of the Zener diode 73 is applied to the transistor 3.
Obtained from 5 emitters. Generally 100 VAC or 2
A low control voltage must be obtained from 00 VAC or its rectified voltage, and if a resistor, a transistor or the like is used, power loss becomes very large. However, if a transformer or a switching power supply is used, power loss will be reduced, but the circuit will be complicated and expensive. Here, as described above, since the chipper part 3 is configured so that the driving signal thereof may be small, the loss in the series regulator can be suppressed to a low level and the structure can be simplified. There are various control circuits for chipping DC power, but here, an example using a circuit of a pulse width modulation system which compares a sawtooth wave oscillation waveform with a control signal and generates a drive signal is used. The oscillator 42 oscillates a sawtooth wave a as shown in FIG. 9, for example, and its oscillation period can be controlled by the resistor 60 or the capacitor 23 connected to the oscillator 42. Here, the resistor 60 is used as a variable resistor to change the oscillation cycle, so that the cycle of the chipper voltage to the electromagnet 4 can be varied. The output of the oscillator 42 and the operational amplifier 41 is connected to the input of the PWM comparator 40. The operational amplifier output b and the sawtooth wave a are compared as shown in FIG. 9, and the sawtooth wave a is larger than the operational amplifier output b. At times, a pulsed voltage c appears at the output of the comparator 40. A transistor 36 is connected to the output of the comparator 40, and the output of the transistor 36 is connected to the base of the transistor 34 of the preceding chipper Iku 3 through a base resistor 52. Therefore, the electromagnet 4 is excited according to the output voltage of the comparator 40. The operational amplifier 41 keeps the excitation voltage of the electromagnet 4 constant. It is connected to the emitter of the transistor 30 of the chipper unit 3, and is connected to the negative side of the control power source by the resistor 59 and the capacitor 22. The side is connected to a resistor 58 connected between the positive and negative lines 104 and 101 of the control power supply. Considering the voltage of the electromagnet 4 before explaining the operation of this circuit, the voltage of the electromagnet 4 is an alternating current, and its line is not at the same level as the negative line 101 of the operational amplifier 41, so that they cannot be connected to each other. However, the voltage between the switching element part on the positive side of the DC power source of the chipper part 3 and the negative line 101 of the DC power source has a part similar to the excitation voltage of the electromagnet 4. For example, it is between the base or emitter of the transistor 30 and the negative line 101 of the DC power supply, and if this voltage is used, the negative side of that voltage is common to the negative side of the operational amplifier 41 and is a DC voltage, so that it is easy to use an electromagnet. Input to the input of operational amplifier 41 as a value proportional to the voltage of 4 Although such a voltage is applied, it becomes a DC voltage that is smoothed by the capacitor 22 and is proportional to the average voltage of the excitation voltage of the electromagnet 4. On the other hand, of the operational amplifier 41 A constant voltage proportional to is applied. Therefore, in this circuit, the exciting voltage of the electromagnet 4 is the operational amplifier. Therefore, the exciting voltage of the electromagnet 4 can be set to an arbitrary value by changing this voltage. In addition, here, the resistors 56 and 57 and the capacitor 21 are This allows the accuracy and stability of this system to be adjusted. With such a simple circuit, even if the voltage of the AC power supply fluctuates, the excitation voltage of the electromagnet 4 can be kept constant so as not to adversely affect the supply speed of the parts of the parts feeder. In addition, in the embodiment of FIG. 8, only the parts which are related to the description are shown using the transistor, but the same effect can be obtained by using the MOSFET. (F) Effects of the Invention As described above, according to the present invention, the circuit structure is very simple, so that there are peculiar effects such as small size, light weight, low cost, and high efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the basic principle of the present invention. FIG. 2 is a block diagram of a conventional vibration generator, FIG. 3 is a waveform diagram for explaining FIG. 2, and FIG. FIG. 5 is a circuit diagram for understanding the principle of the present invention, FIG. 5 is a waveform diagram for explaining FIG. 4, FIG. 6 is a circuit diagram showing the basic principle of the present invention, and FIG. 7 is FIG. FIG. 8 is a waveform diagram for explaining the above, FIG. 8 is an embodiment of the present invention, and FIG. 9 is a waveform diagram for explaining the operation of FIG. In the figure, 1 is an AC power supply, 2 is a DC power supply unit, 3 is a chipper unit, 4 is an electromagnet, 5 is a control unit, 6 is a vibrating body, and 7 is a spring.

Claims (1)

(1) A direct current source section 2 obtained by rectifying an alternating current power source 1 with a diode, and a tipper section 3 for tipping a direct current voltage of a direct current power source section 2 to output a periodic pulsating current voltage of a rectangular wave. An electromagnet 4 that is excited by the output of the control unit 5 and the chipper unit 3 to generate an attractive force, a vibrating body 6 that is driven by the electromagnet 4, and a spring 7 that supports the vibrating body 6. In the above-described structure, the vibration generator is configured such that the cycle of the chopping voltage is changed to change the frequency of the vibrating body 6, and the width of the chopping voltage is changed to change the amplitude of the vibrating body 6. (2) The chipper section 3 includes two sets of switching elements 3
The vibration generator according to claim (1) having a main circuit in which 0 and 31 and two sets of diode elements 71 and 72 are connected to a bridge. (3) An amplifier circuit is provided in the preceding stage to drive the two sets of switching elements 71 and 72. The amplifier circuit is constituted only by the connection on the side of each DC line to which each switching element is connected. Amplification circuit for both lines 1 at the front stage
It is connected to one switching element 34 and driven by one drive signal. Claim (2) configured as described above
The vibration generator according to the item. (4) The vibration generation according to claim (3), in which a series regulator circuit is used to obtain a control power source by increasing the amplification degree of the amplifier circuit to suppress the output current of the control unit 5 to a low level. apparatus. (5) The control unit 5 detects a voltage waveform similar to the exciting voltage of the electromagnet 4 from one line of the switching element unit and the DC power supply, and controls the exciting voltage of the electromagnet 4 to a constant value. A vibration generator according to item (2).