JPWO2006035938A1 - Oscillating magnetic field generator, electromagnet drive circuit, and parts feeder using them - Google Patents

Abstract

The simple oscillating magnetic field generator is improved to reduce the time constant of the electromagnetic energy emission circuit and to suppress the heat generation in the electromagnet to stabilize the oscillating magnetic field. An oscillating magnetic field generator 120 according to the present invention includes an electromagnet 4 having an inductance L and a resistance value r, and an electromagnet drive circuit 5 that drives the electromagnet 4, and supplies an excitation current to the electromagnet 4 from a DC power source 11, thereby providing an electromagnet drive circuit. Reference numeral 5 denotes a switching element 12 that controls the excitation current on / off, an electromagnetic energy emission circuit that releases energy stored in the electromagnet 4 when the switching element 12 is off, and a pulse that generates a pulse signal to be supplied to the switching element 12. The electromagnetic energy emission circuit includes a generation unit 10, and a circuit in which a resistor 14 having a resistance value R larger than the resistance value r is connected in series to the diode 13 is connected in parallel to the electromagnet 4, and the pulse signal Is periodically supplied to the switching element 12 to generate an oscillating magnetic field having a period of a pulse signal in the electromagnet 4. That.

Description

  The present invention relates to an oscillating magnetic field generator, an electromagnet drive circuit, and a parts feeder using them. Specifically, the present invention relates to an oscillating magnetic field generator that vibrates a resonant parts feeder, an electromagnet drive circuit that is a part thereof, and a resonant parts feeder that uses them to supply components in accordance with the period of vibration.

  Conventionally, in order to set immunoassay parts such as chips, cuvettes, and cartridges in a measuring apparatus, a large number of parts are manually taken out of the box, and are arranged side by side and set in the measuring apparatus.

  Therefore, the inventors have been developing a parts feeder for automating the process of supplying parts to the measuring device.

  On the other hand, as a method of generating vibration with an electromagnet, a method of periodically turning on and off an electromagnet switch can be mentioned. Incidentally, the coil of the electromagnet has a relatively large inductance L and a relatively small resistance value r. The rise and rise of the drive current (also called the coil current, which is divided into the excitation current during excitation and the energy release current during energy release (demagnetization) stored in the electromagnet) when turning on / off such a coil switch. The time constant that determines the down speed is as large as L / r.

An inductive load control device is disclosed in which the current response is improved by reducing the time constant when discharging stored energy of an inductive load such as an electromagnet coil. (See Patent Document 1)
FIG. 8 shows an outline of a circuit configuration of the inductive load control device. In FIG. 8, a circuit in which an inductive load 52, a detection coil 53 of a current detection sensor, and an impedance element 54 are connected in series is connected to a DC power source 51, and further connected to a ground 57 through a switching element SW1. A diode 55 (connected in the reverse direction) and a capacitor 56 are connected in parallel to the series connection circuit, and a switching element SW2 is connected in parallel to the impedance element 54. When the switching element SW1 is on / off controlled by a PWM (pulse width modulation) signal, the switching element SW2 is turned on. When the switching element SW1 is turned on, the inductive load 52, current When the current I1 flows to the inductive load 52 through the detection coil 53, the switching element SW2, the switching element SW1, and the ground 57 of the detection sensor and the switching element SW1 is turned off, the accumulated energy is detected by the detection coil of the current detection sensor. 53, flows through the switching element SW 2 and the diode 55 as a current I 2, and returns to the DC power source 51. The capacitor 56 is for absorbing a surge generated when a current flows through the diode 55. When the PWM signal output is turned off and the switching element SW1 is turned off, the switching element SW2 is also turned off, and the stored energy passes through the detection coil 53, the impedance element 54, and the diode 55 of the current detection sensor. However, since the impedance element 54 is connected in series to the inductive load 52 and the circuit time constant is small, the current at that time is rapidly attenuated, and the responsiveness of the inductive load 52 is improved. The detection coil 53 of the current detection sensor controls the PWM signal output by detecting the current flowing through the inductive load 52 and comparing it with a specified current value.

JP-A-7-143793 (paragraphs [0036] to [0045], FIGS. 1 to 4 etc.)

  The resonance type parts feeder developed by the inventors is a part that vibrates a parts transfer path for moving parts, aligns the parts, and supplies parts one by one continuously and automatically according to the vibration. It is a feeder, and it has the advantage that a large amplitude can be obtained with low power by matching the natural frequency of the vibration mechanism of the parts feeder and the frequency of the drive circuit, but it can supply parts efficiently, but on the other hand, temperature When the natural frequency changes due to changes, assembly adjustments, impacts, changes with time, etc., there is a drawback that the resonance is lost and the amplitude is reduced.

  As a countermeasure against this instability, it is possible to employ a resonance ensuring means that monitors the natural frequency of the vibration mechanism of the parts feeder and corrects the drive frequency, but the drive circuit is complicated and large. In contrast, parts feeders that do not employ resonance securing means have the advantage that the drive circuit is simple and easy, but on the other hand, because the vibration is unstable, the parts supply capability is unstable, Often, the entire device could fail.

  For example, an electromagnet is used as a vibration element for applying vibration to the resonance type parts feeder. However, in order to achieve a stable operation, it is effective to suppress the heat generation of the electromagnet. Therefore, the coil of the electromagnet has a small resistance value r. Those having a relatively large inductance L are employed.

  With respect to an oscillating magnetic field generator using such an electromagnet, as will be described later with respect to a comparative example, there is no problem because the excitation current rises quickly during excitation, but when electromagnetic energy is released, the energy emission current rises. Since the time constant of the fall is long, there is a problem that the coil current does not fall easily and the vibration frequency cannot be set high. In addition, when the frequency is increased, the next ON operation starts before the current sufficiently decreases, and a wasteful current that does not contribute to vibration continues to flow, and all this wasteful current is consumed as heat is generated in the coil. There was a problem. Further, in an oscillating magnetic field generator that employs such a simple drive circuit, all of the energy stored in the electromagnet is consumed as heat generated in the coil while the electromagnet is off, and the temperature of the electromagnet rises, driving the electromagnet. There was a problem of disturbing the period and destabilizing the vibration of the parts feeder.

  Even if the technology in the inductive load control device of the conventional example is applied to the oscillating magnetic field generator as it is, when the on / off control is performed with the PWM signal, the stored energy does not flow through the impedance element, so the time constant becomes small. Therefore, the above problem cannot be solved. Therefore, it is necessary to improve the configuration of the electromagnet driving circuit so that the stored energy flows through the impedance element even when on / off control is performed.

  The present invention improves the oscillating magnetic field generator and the inductive load control device adopting the simple drive circuit, reduces the time constant of the electromagnetic energy release circuit, suppresses heat generation in the electromagnet, The purpose is to stabilize the oscillating magnetic field. It is another object of the present invention to apply a oscillating magnetic field generator employing such a simple drive circuit to a parts feeder so that stable automatic component supply can be performed through stable vibration.

  In order to solve the above problems, an oscillating magnetic field generator according to the present invention is an oscillating magnetic field generator comprising an electromagnet 4 and an electromagnet drive circuit 5 for driving the electromagnet 4 as shown in FIG. Has an inductance L and a resistance value r, and the electromagnet drive circuit 5 includes terminals A and D for connection to a DC power source 11 that supplies an excitation current to the electromagnet 4, a switching element 12 that controls on / off of the excitation current, When the switching element 12 is off, it has an electromagnetic energy release circuit that releases energy stored in the electromagnet 4 and a pulse generation means 10 that generates a pulse signal to be supplied to the switching element 12. A circuit in which a diode 13 and a resistor 14 having a resistance value R that is larger than the resistance value r is connected in series is connected in parallel to the electromagnet 4 so that a pulse signal is transmitted. By periodically supplied to the switching element 12 to generate an oscillating magnetic field with a period of the pulse signal to the electromagnet 4.

  Here, the electromagnet drive circuit 5 is used by being connected to the DC power supply 11, but it may be connected to the DC power supply during distribution in the market or the like. When the terminals A and D of the electromagnet driving circuit 5 are connected to the positive and negative electrodes of the DC power supply 11, respectively, the electromagnet 4 is connected to the terminal A and the switching element 12 is connected to the electromagnet 4 as shown in FIG. The terminal B may be connected between the terminal B and the terminal D on the opposite side of A, or the electromagnet 4 may be connected to the terminal D, and the switching element 12 may be connected to the terminal D on the side opposite to the terminal D of the electromagnet 4. You may connect between A. The diode 13 is typically used in the reverse direction, that is, with the cathode connected to the terminal A side and the anode connected to the terminal B side. If comprised in this way, in the electromagnet drive circuit 5, the time constant of an electromagnetic energy discharge | release circuit can be reduced, the heat_generation | fever in the electromagnet 4 can be suppressed, and an oscillating magnetic field can be stabilized.

  The time constant is determined by the inductance L and the resistance value r of the electromagnet 4, and since the inductance L is large, it is relatively large as L / r. The present invention enables stabilization of the oscillating magnetic field by inserting a large resistance value R in the electromagnetic energy emission circuit, reducing the time constant, and suppressing heat generation. Has been confirmed to be obtained.

  Further, according to a preferred aspect of the oscillating magnetic field generator according to the present invention, the switching element 12 is constituted by an insulated gate type element, and the pulse generating means 10 determines the cycle of the switching pulse supplied to the switching element 12 element. It has a first timing generator 18 and a second timing generator 19 that defines the width of the switching pulse on the high level side. With this configuration, the pulse period and the ratio between the pulse width on the high level (H level) side and the pulse width on the low level (L level) side can be adjusted independently, so that a desired duty can be obtained at a desired frequency. It becomes easier to generate rate switching pulses.

  The electromagnet drive circuit according to the present invention is an electromagnet drive circuit 5 for driving an electromagnet 4 having an inductance L and a resistance value r as shown in FIG. Terminals A and D for connection to the switching element 11, a switching element 12 for controlling on / off of the exciting current, an electromagnetic energy emission circuit for discharging energy stored in the electromagnet 4 when the switching element 12 is off, and a switching element 12 The electromagnetic energy emission circuit includes a diode 13 and a resistor 14 having a resistance value R larger than the resistance value r in series. 4 is connected in parallel, and the pulse signal is periodically supplied to the switching element 12 so that the electromagnet 4 has a cycle of the pulse signal. To generate an oscillating magnetic field. It is invention of the electromagnet drive circuit corresponding to the oscillating magnetic field generator which concerns on this invention.

Further, the parts feeder according to the present invention is taken in from the vibration magnetic field generator 120 according to the present invention, the part taking-in part 101 for taking in a large number of parts 6, and the part taking-in part 101 as shown in FIG. The parts transfer path 1 for moving the parts 6 while aligning them, the parts supply unit 102 for supplying the parts 6 transferred along the parts transfer path 1 one by one, and the parts transfer path 1 are installed to generate the oscillating magnetic field. A main body 110 having a vibration table 2 that receives vibration magnetic field from the device 120 and applies vibration to the parts transfer path 1, and applies vibration to the parts transfer path 1 by the vibration magnetic field generated by the vibration magnetic field generator 120. Thus, the component 6 is moved along the parts transfer path 1 while being aligned.
With this configuration, by applying the oscillating magnetic field generator according to the present invention to the parts feeder, a simple electromagnet driving circuit that does not take resonance securing means, and stable automatic component supply via stable vibration can be achieved. Possible parts feeder can be provided.

  Moreover, according to the preferable aspect of the parts feeder which concerns on this invention, as shown, for example in FIG. 1, the power supply 130 which supplies electric power to the main-body part 110 and the oscillating magnetic field generator 120 is provided. This configuration is convenient because it can be managed and transported integrally with the power source.

  Moreover, according to the preferable aspect of the parts feeder which concerns on this invention, it can adjust so that the frequency of an oscillating magnetic field may be matched with the natural frequency of an own vibration mechanism. If comprised in this way, stable resonance vibration can be maintained by adjusting to the resonance vibration which matched the natural frequency of the vibration mechanism of the parts feeder 100, and the electromagnet 4 can be maintained, and the supply process of a parts feeder can be made efficient. . Adjustment is possible, for example, with the first timing generator 18 (see FIG. 5).

  Moreover, the automatic immunity measuring device according to the present invention includes the parts feeder according to the present invention. If comprised in this way, parts supply will be performed automatically and the automatic immunoassay apparatus which can perform an automatic measurement can be provided. The automatic immunoassay device typically includes a solid phase reagent, a labeling reagent, and a specimen that specifically recognize and bind to a measurement target in a reaction vessel such as a cuvette based on an enzyme immunoassay. It is an apparatus that detects a measurement object in a sample by mixing.

  According to the present invention, in the oscillating magnetic field generator that employs a simple drive circuit in which no resonance securing means is taken, the time constant of the electromagnetic energy release circuit is reduced, and the heat generation in the electromagnet is suppressed, The oscillating magnetic field can be stabilized. In addition, by applying the oscillating magnetic field generator according to the present invention to a parts feeder, it is possible to provide a parts feeder capable of supplying stable automatic parts through stable vibration.

This application is based on Japanese Patent Application No. 2004-287683 filed on September 30, 2004 in Japan, the contents of which form part of the present application.
The present invention will be more fully understood from the following detailed description. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, the detailed description and specific examples are preferred embodiments of the present invention and are provided for illustrative purposes only. From this detailed description, various changes and modifications will be apparent to those skilled in the art within the spirit and scope of the invention. The applicant does not intend to contribute any of the described embodiments to the public, and modifications and alternatives that may not be included in the scope of the claims within the scope of the claims are also subject to equivalence. As part of the invention.
In this description or in the claims, the use of nouns and similar directives should be understood to include both the singular and the plural unless specifically stated otherwise or clearly denied by context. The use of any examples or exemplary terms provided herein (eg, “etc.”) is merely intended to facilitate the description of the invention and is specifically recited in the claims. Unless otherwise specified, the scope of the present invention is not limited.

It is a figure which illustrates the outline | summary of a structure of a resonance type feeder. It is a figure for demonstrating the vibration mechanism of a resonance type parts feeder. It is a figure which shows the structural example of the oscillating magnetic field generator by embodiment of this invention. It is a figure which shows the example of the electric current characteristic in the oscillating magnetic field generator by embodiment of this invention. It is a figure which shows the structural example of the electromagnet drive circuit by embodiment of this invention. It is a figure which shows the structural example of the oscillating magnetic field generator of a comparative example. It is a figure which shows the example of the current characteristic in the oscillating magnetic field generator of a comparative example. It is a figure which shows the outline of the circuit structure of the conventional inductive load control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Parts transfer path 2 Shaking table 2A Armature 3 Leaf spring 4 Electromagnet 5 Electromagnet drive circuit 6 Parts 7 Parts storage box 8 Slope 9 Groove 10 Pulse generation means 11 DC power supply 12 Switching element 13 Diode 14 Resistor 15 Fuse 16 Regulator 17 DC bus 18 First timing generator 19 Second timing generator 20 Photocoupler 51 DC power supply 52 Inductive load 53 Current detection sensor detection coil 54 Impedance element 55 Diode 56 Capacitor 57 Ground 100 Resonant type parts feeder 101 Parts receiving section 102 Component supply section 110 Main body section 120 Oscillating magnetic field generators A, B, D Terminals C1 to C4 Capacitor E DC power supply voltage i (t), I Coil current L Inductance N1 to N7 of electromagnet 4 Terminal r Resistance value of electromagnet 4 R resistance 14 Period of resistance values R1, R2 variable resistor R3~R6 resistor SW1, SW2 switching element T pulse signal

  First, as a comparative example, driving of an electromagnet used for a prototype resonant feeder during development will be described.

  In FIG. 6, the structural example of the oscillating magnetic field generator of a comparative example is shown. The comparative example is an example in which an electromagnet is used as a vibration element of a resonance type part feeder, and a simple drive circuit in which resonance ensuring means is not taken is employed. The coil of the electromagnet 4 has a relatively large inductance L and a relatively small resistance value r. One terminal A of the electromagnet 4 is connected to the positive electrode of the DC power supply 11, the other terminal B of the electromagnet 4 is connected to a switching element 12 such as a power MOSFET (insulated gate field effect transistor), and the other terminal of the switching element 12. Is connected to the negative electrode D of the DC power supply 11. Further, a diode 13 is connected between the terminals A and B in parallel with the electromagnet 4 as an electromagnetic energy emission circuit in the reverse direction, that is, with the cathode on the terminal A side and the anode on the terminal B side. The pulse generating means 10 is connected to the gate of the switching element 12.

  At the time of excitation, an H level pulse signal is supplied from the pulse generating means 10 to the gate of the switching element 12 to turn on the switching element 12, and the positive electrode of the DC power source 11 → the electromagnet 4 → the switching element 12 → the negative electrode of the DC power source 11. Current flows through route D. Since a reverse voltage is applied to the diode 13, no current flows. Thereby, the electromagnet 4 is excited to magnetize and attract the armature (movable piece) 2A attached to the vibration table 2 (see FIG. 2).

  When electromagnetic energy is released, an L level pulse signal is supplied from the pulse generating means 10 to the gate of the switching element 12, the switching element 12 is turned off, and the DC power supply 11 is shut off from the electromagnet 4. The energy accumulated in the electromagnet 4 is returned to the electromagnet 4 as a current passing through the electromagnetic energy release circuit of the terminal B of the electromagnet 4 → the diode 13 → the terminal A of the electromagnet 4. That is, an electromagnetic energy release loop of electromagnet 4 → diode 13 → electromagnet 4 is formed. In the electromagnet 4, heat is generated and consumed as Joule heat at the internal resistance r.

  FIG. 7 shows an example of current characteristics in the oscillating magnetic field generator of the comparative example. FIG. 7A shows a pulse signal supplied to the gate of the switching element 12, and FIG. 7B shows a current flowing through the electromagnet 4 (repetition of excitation current and energy emission current).

  The coil current at the time of excitation, that is, when the electromagnet is turned on is expressed by (Equation 1). In (Equation 1), i (t) represents the coil current as a function of time t, E represents the supply voltage of the DC power supply 11, and ε represents the exponential (ε = 2.71828...). In FIG. 7B, the current rises quickly at the time of excitation, so no particular problem has occurred.

i (t) = E / r (1−ε ^{(−rt / L)} ) (Formula 1)

  On the other hand, when electromagnetic energy is released, there is a problem that the coil current does not decrease easily because the time constant is long, and the vibration frequency cannot be set high. Further, when the frequency is increased, the next ON operation starts before the current sufficiently decreases as shown in FIG. 7B, and a wasteful current that does not contribute to vibration continues to flow (if the minimum current value is 0). In other words, a current below the minimum current value is a wasteful current.) However, there is a problem that all this wasteful current is consumed as heat is generated in the coil.

Further, such a simple driving circuit, the coil between the electromagnets 4 on (LI ^2/2) (I is the coil current) the energy of is stored, the heat generation of the coil during all this energy electromagnet 4 off There is a problem that the temperature of the electromagnet 4 rises.

  Further, in the resonance type part feeder in the comparative example, since the heat generated by the electromagnet is large as described above, there is a problem that the vibration is out of the resonance state and becomes unstable, often resulting in failure of the apparatus.

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

  FIG. 1 illustrates an outline of the configuration of a resonance type part feeder. Reference numeral 100 denotes a resonance type part feeder, which includes a main body 110, an oscillating magnetic field generator 120, and a power source 130. The main body 110 is transferred along the parts taking-in part 101 for taking in a large number of parts 6, the parts transfer path 1 for moving the parts 6 taken in from the parts taking-in part 101 while aligning them, and the parts transferring path 1. And a component supply unit 102 for supplying the components 6 one by one. In addition, the parts transfer path 1 is mounted, and a vibration table 2 that receives vibration magnetic fields from the vibration magnetic field generator 120 and applies vibrations to the parts transfer path 1 is provided. The oscillating magnetic field generator 120 includes an electromagnet 4 that generates an oscillating magnetic field and an electromagnet drive circuit 5 that drives the electromagnet 4. The power supply 130 supplies power to the main body 110 and the oscillating magnetic field generator 120 (the electromagnet 4 and the electromagnet drive circuit 5).

  FIG. 2 is a diagram for explaining the vibration mechanism of the resonance type part feeder. FIG. 2A is a diagram showing the concept of the vibration mechanism, and FIG. 2B is an enlarged perspective view conceptually showing the parts transfer path. The parts transfer path 1 is fixedly mounted on the stage of the vibration table 2, and an iron plate as an armature 2 </ b> A is attached in the vicinity of the attracting portion of the electromagnet 4 disposed on the lower surface of the vibration table 2. A leaf spring is used for the support leg 3 of the vibration table 2 and is urged so as to separate the vibration table 2 from the electromagnet. The armature 2A and the support leg 3 are included in the vibration table 2. When the electromagnet drive circuit 5 performs on / off control of a drive current (also called a coil current, which is referred to as an excitation current in the on state and an energy release current in the off state) flowing in the coil of the electromagnet 4, the electromagnet 4 is excited at the on time. Then, the leaf spring 3 is bent to attract the armature 2A together with the stage, and when it is off, the electromagnet 4 is demagnetized, and the vibration table 2 returns to its original state by the force of the leaf spring. By repeating on / off, the vibration table 2 and the parts transfer path 1 vibrate.

  A parts storage box 7 serving as a parts receiving portion 101 is provided above the parts transfer path 1, and a large number of parts 6 (usually one type) such as chips, cuvettes, cartridges, etc. are stored therein. When the bottom of the parts storage box 7 is opened, a large number of parts 6 are dropped and supplied from the parts storage box 7 to the parts transfer path 1 and rolls on the slope 8 of the parts transfer path 1 to form grooves 9 provided in the parts transfer path 1. It is configured to fall and align. The part 6 has a cylindrical shape or a conical shape which is symmetric with respect to the central axis, and its main body part is formed in the groove 9 and only the head part is formed on the groove 9. The width of the groove 9 is such that the part 6 has a width. It is formed wider than the main body portion of the component and narrower than the head portion so as to be aligned in a line along the groove 9. When the electromagnet 4 is turned on and off, an oscillating magnetic field is generated, and vibration is transmitted to the parts transfer path 1 via the vibration table 2. In the vibration, the parts 6 that have fallen on the slope 8 are moved to fall into the grooves 9 and aligned in a row along the grooves 9, and the parts 6 aligned in the grooves 9 in accordance with the vibrations are transferred one by one to the parts transfer path 1. Move in the forward direction. The parts 6 moved forward in the parts transfer path 1 reach a parts supply unit 102 (not shown), and are picked up one by one in synchronization with the operation of a predetermined processing apparatus to which the parts are supplied, and supplied to the predetermined processing apparatus. Is done.

  Examples of the predetermined processing apparatus include an automatic immunoassay apparatus. When such a parts feeder is incorporated in an automatic immunoassay device, a reagent dispensing unit or the like is applicable. Since these parts are automatically supplied from the parts feeder to these processing apparatuses, automatic processing becomes possible. Note that an automatic immunoassay device typically mixes a solid phase reagent, a labeling reagent, and a specimen that specifically recognizes and binds to a measurement object in a reaction vessel such as a cuvette based on an enzyme immunoassay. Thus, it is an apparatus for detecting a measurement object in a specimen.

  FIG. 3 shows a configuration example of the main part of the oscillating magnetic field generator according to the embodiment of the present invention. The coil of the electromagnet 4 has a relatively large inductance L and a relatively small resistance value r. One terminal A of the electromagnet 4 is connected to the positive electrode of the DC power supply 11, the other terminal B of the electromagnet 4 is connected to the drain of the power MOSFET as the switching element 12, and the source of the power MOSFET 12 is connected to the negative electrode D of the DC power supply 11. It is connected. Further, in parallel with the electromagnet 4 between the terminals A and B, a diode 13 and a resistor 14 having a resistance value R larger than the resistance value r are connected in series as an electromagnetic energy emission circuit. They are connected in the opposite direction, that is, with the cathode on the terminal A side and the anode on the terminal B side. The pulse generating means 10 is connected to the gate of the switching element 12. Note that the resistance value Rd of the diode 13 is very (sufficiently) smaller than the resistance value (R + r), and therefore can be ignored when performing various energy calculations. Terminals A, B, and D are also terminals of the electromagnet driving circuit 5, and the electromagnet driving circuit 5 is connected to the electromagnet 4 and the DC power source 11 at the terminal A, connected to the electromagnet 4 at the terminal B, and also connected to the terminal D Is connected to the negative electrode side of the DC power supply 11. The only difference from the comparative example of FIG. 6 is that a resistor 14 is added to the electromagnetic energy emission circuit.

  Further, as compared with the conventional example of FIG. 8, instead of the impedance connected between the inductive load (corresponding to an electromagnet) and the switching element SW1, a resistor 14 is connected in series with the diode 13 and an electromagnetic energy emission circuit. The switching element SW2 is omitted, the number of switching elements is one, and the surge current absorbing capacitor is also omitted. As a result, the energy emission current when the switching element 12 is turned off flows through the resistor 14, and the time constant of the electromagnetic energy emission circuit becomes small, so that the energy emission current can be attenuated quickly.

  At the time of excitation, an H level pulse signal is supplied from the pulse generating means 10 to the gate of the switching element 12 to turn on the switching element 12, and the positive electrode of the DC power source 11 → the electromagnet 4 → the switching element 12 → the negative electrode of the DC power source 11. Current flows through route D. Since a reverse voltage is applied to the diode 13, no current flows. Thereby, the electromagnet 4 is excited to magnetize and attract the armature 2A of the vibration table 2.

  When electromagnetic energy is released, an L level pulse signal is supplied from the pulse generating means 10 to the gate of the switching element 12, the switching element 12 is turned off, and the DC power supply 11 is shut off from the electromagnet 4. The energy accumulated in the electromagnet 4 is returned to the electromagnet 4 as a current passing through the electromagnetic energy release circuit of the terminal B of the electromagnet 4 → the diode 13 → the resistor 14 → the terminal A of the electromagnet 4. That is, an energy release loop of electromagnet 4 → diode 13 → resistor 14 → electromagnet 4 is formed.

  FIG. 4 shows an example of current characteristics in the oscillating magnetic field generator of FIG. FIG. 4A shows a pulse signal supplied to the gate of the switching element 12, and FIG. 4B shows a current flowing through the coil of the electromagnet 4 (repetition of excitation current and energy emission current).

  At the time of excitation, that is, when the electromagnet is turned on, the rise of current is as fast as in FIG. On the other hand, when the electromagnetic energy is released, the resistance value of the energy release loop is (r + R), so that the time constant is L / (r + R) based on the inductance L and the resistance value (r + R), which is compared with the conventional L / r. Therefore, the energy emission current approaches 0 quickly. Since the resistance value Rd of the diode 13 is sufficiently smaller than the resistance value (R + r), it can be ignored when calculating the time constant. Therefore, it is possible to quickly switch from the off state to the on state, and the frequency of the pulse signal can be increased.

  Further, as shown in FIG. 4B, after the current is sufficiently lowered, the next electromagnet 4 can be turned on, and the useless steady current that does not contribute to vibration is reduced. FIG. 4B shows an example of a current waveform when the resistance value R inserted into the electromagnetic energy emission circuit is about twice the internal resistance value r of the electromagnet 4. In this example, L = 48 mH, r = 2.4Ω, and R = 5Ω were used as the inductance and resistance values. Although a relatively small value is used as the resistance value R, the driving current is shifted to the low current side by about 0.4 A compared to FIG. is decreasing.

Further, Joule heat R / (r + R) of the ^(LI 2/2) is consumed by the resistor 14, the amount that is consumed in the electromagnet 4 is reduced and r / (r + R), consumed by the heat generation of the electromagnet 4 The amount of heat generated can be greatly reduced, and the temperature rise of the electromagnet 4 can be suppressed. Again, the resistance value Rd of the diode 13 is sufficiently smaller than the resistance value (R + r), and can be ignored when the Joule heat is calculated. Thereby, the oscillating magnetic field of the oscillating magnetic field generator 120 after power-on and the oscillating operation of the parts feeder 100 can be greatly stabilized.

  The larger the resistance value R of the resistor 14 is, the more effective, but since a reverse voltage generated by multiplying the resistance value R by the coil maximum current value Imax is generated at both ends of the resistor 14, the resistance of the switching element 12 is within the allowable range. Set to an appropriate value. For this reason, the resistance value R is preferably 2 to 10 times the resistance value r. With this configuration, the time constant can be reduced to 1/3 or less, and the heat generation of the electromagnet can be suppressed to 1/3 or less (the coil current itself can also be reduced, so that it can be further reduced). The vibration magnetic field and the vibration of the parts feeder 100 can be greatly stabilized. The lower limit of the resistance value is a value that does not affect the stability of the vibration magnetic field and the vibration of the parts feeder 100 due to a decrease in the time constant, and the upper limit is a value that does not affect the reverse voltage generated in the resistor 14. Further, the maximum current value Imax of the resistor 14 is the same as the maximum current of the coil, and the maximum power consumption is a value obtained by multiplying R / (r + R) of the power stored in the coil when the electromagnet is on by the frequency.

  FIG. 5 shows a configuration example of an electromagnet driving circuit according to the embodiment of the present invention. The same components as those in FIG. 3 are denoted by the same reference numerals and description thereof is omitted. Although it is the same as that of the structure of FIG. 3, the pulse generation means 10 is connected to the switching element 12 via the resistor R4 in that it is connected to the DC power supply 11 via the fuse 15 for protecting the electromagnet drive circuit. The point is different. The supply voltage of the DC power supply 11 is set to, for example, 24 V so that a current that can provide a sufficiently large vibration (or oscillating magnetic field) can be supplied.

  Reference numeral 16 denotes a series regulator which reduces the voltage of 24V to 5V. The capacitor C1 connected to the input side of the series regulator 16 and the capacitor C2 connected to the output side of the series regulator 16 are for smoothing the voltage. The output terminal of the series regulator 16 is connected to the DC bus 17 and supplies a voltage of 5V to the pulse generator 10 via the DC bus 17.

  The pulse generation means 10 has a first timing generator 18 and a second timing generator 19, and the first timing generator 18 and the second timing generator 19 respectively supply a voltage of 5 V from the DC bus 17. Then, a pulse signal for driving the electromagnet supplied to the switching element 12 is generated in cooperation. By periodically supplying the pulse signal to the switching element 12, an oscillating magnetic field having a period T of the pulse signal is generated in the electromagnet 4.

  In the first timing generator 18, a variable resistor R1 is connected between the DC bus 17 and the terminal N1 of the first timing generator 18, a resistor R3 is connected between the terminal N1 and the terminal N2, and a capacitor C3 is connected between the terminal N2 and the ground terminal D. The first timing generator 18 is a simple transmission circuit that uses, for example, an unstable operation of a timer circuit, and the frequency (frequency) of electromagnet on / off, that is, the period T (H level time of the gate signal of the switching element 12). Width + L level time width). This time is set by a combination of the resistor R1, the resistor R3, and the capacitor C3. Here, for the sake of simplicity, here, these resistance values and capacitances are R1, R3, and C3.

The H level time width Th ₁ and the L level time width Tl ₁ of the output are expressed by the following equations.

Th ₁ = Ln2 × (R1 + R3) × C3 (Formula 2)
Tl ₁ = Ln2 × R3 × C3 (Formula 3)

The total period T is expressed by the following equation.

T = Th ₁ + Tl ₁ = Ln2 × (R1 + 2 × R3) × C3 (Formula 4)

The frequency f is the reciprocal of the period.

f = 1 / T = 1.44 / ((R1 + 2 × R3) × C3) (Formula 5)

For example, when the resistance value R1 is variable from 150 KΩ to 1.15 MΩ and the capacitance C3 and the resistance value R3 are appropriately selected (here, C3 = 0.1 μF, R3 = 2 kΩ), the frequency f = 12 Hz to 94 Hz is obtained. Thus, the L level time width Tl ₁ becomes 0.14 mS independently of the setting of the resistance value R1, and the H level time width Th ₁ can be changed from 10 mS to 83 mS depending on the setting of the resistance value R1. This is a reasonable value because the target is 10 to 100 Hz in the design stage. The frequency range can be changed by changing the range of the resistance value R1, the resistance value R3, and the capacitance C3.

It is preferable to make the frequency f of the circuit coincide with the natural frequency of the parts feeder because a resonance state is obtained and energy transfer is performed efficiently. The natural frequency of the parts feeder is set to 60 Hz as a design value, for example. However, each product has subtle variations in its natural frequency. Therefore, fine adjustment is performed to match the natural frequency of each part feeder with the frequency of the circuit at the time of shipment or installation. In addition, the natural frequency of the parts feeder may be changed by changing the specification. Therefore, adjustment is possible in the range of about 10 to 100 Hz so that the frequency of the circuit can be matched with the natural frequency of the parts feeder.
The output terminal N3 of the first timing generator 18 is connected to the input terminal N6 of the second timing generator 19.

In the second timing generator 19, a variable resistor R2 is connected between the DC bus 17 and the terminal N4, and a capacitor C4 is connected between the terminal N4 and the ground D. The timing generator 19 is a circuit called a one-shot multivibrator that uses a monostable operation of a timer circuit, for example, and sets the ratio of the H level time width Th ₂ and the L level time width Th ₂ . This ratio is determined by resistor R2 and capacitor C4. Here, for the sake of simplicity, these resistance values and capacitances are R2 and C4. The frequency f is unchanged and maintains the frequency output from the first timing generator 18. The output signal is output from the output terminal N7 and input to the gate of the switching element 12 via the resistor R4.

The timing generator 19 holds the output at the H level for a certain period of time triggered by the falling edge of the input signal. The H level time width Th ₂ is expressed by the following equation.

Th ₂ = 1.1 × R2 × C4 (Formula 6)

For example, when calculation is performed by substituting the resistance value R2 (10 to 110 KΩ) and the capacitance C4 (0.068 μF), the H level time width Th ₂ becomes 0.75 ms to 8.2 ms. This is a reasonable value because the target is about 1 to 8 ms at the design stage. For example, it can be set around 4 ms.
The L level time width Tl ₂ depends on the resistance value R1 and the resistance value R2, and is expressed by the following equation.

Tl ₂ = (1 / f−Th ₂ ) (Expression 7)

  N5 is an input terminal for a reset signal. When the input terminal is maintained at the L level, the output is fixed at the L level, the electromagnet 4 is off, and no vibration is applied to the shaking table 2. When a control signal of 24V is applied between the terminal N8 and the terminal N9, a current flows in the order of the resistor R5, the light emitting diode (LED) D2 for monitoring, and the light emitting diode D3 of the photocoupler 20, and the light emitting diode D2 is turned on. . When a current flows through the light emitting diode D3, the phototransistor T2 is turned on, the input terminal N5 becomes H level, and the second timing generator 19 is activated. In this state, the electromagnet 4 is driven on and off to apply vibration to the parts feeder.

On the other hand, when the control signal of 24V is lost between the terminals N8 and N9, the light emitting diode D2 is turned off, the phototransistor T2 is turned off, the input terminal N5 becomes L level, and the second timing generator 19 is turned on. Reset and stop operation. In this state, the output terminal N7 is maintained at the L level, and the switching element 12 is kept off. The reason why the photocoupler 20 (D3-T2) is used is to insulate the control signal from the drive system power supply and prevent the noise from entering the pulse generating means 10.
The resistor R4 is for protecting the circuit so that an excessive current does not flow due to the gate input capacitance of the switching element 12.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made to the embodiments without departing from the spirit of the present invention. It is.

  For example, although an example in which a power MOSFET is used as the switching element 12 has been described in the present embodiment, a JFET (junction transistor) may be used, or an IGBT (insulated gate bipolar transistor) may be used. Although a bipolar transistor may be used, it is necessary to use a large number of control ICs and transistors, and the amount of heat generation increases, so it is preferable to use an insulated gate type element. Moreover, although the example which uses the series regulator 16 for converting 24V voltage into 5V voltage was shown, it replaced with the series regulator 16 and may use a DC-DC converter. However, since a DC-DC converter may be a noise source, it is preferable to use a series regulator.

  Further, an electromagnet driving (24V) power source and a timing generating circuit (5V) power source may be provided separately. In addition, although an example in which one resistor 14 is used to insert the resistance value R has been described, a plurality of resistors connected in series and in parallel are used in an equivalent circuit that can obtain the resistance value R. For example, two resistors may be arranged separately above and below the diode 13. Further, instead of the diode 13 in the reverse direction, a switch that turns on when the switching element 12 is turned off and turns off when the switching element 12 is turned on may be provided. Also, the configuration of the pulse generating means for controlling the switching element 12 can be variously changed.

The present invention is used for an oscillating magnetic field generator for applying vibration to a resonance type part feeder. In addition, a resonance-type parts feeder incorporating an oscillating magnetic field generator is used for an automatic immunoassay device or the like.

Claims (7)

An oscillating magnetic field generator comprising an electromagnet and an electromagnet drive circuit for driving the electromagnet;
The electromagnet has an inductance L and a resistance value r;
The electromagnet driving circuit includes a terminal for connecting to a DC power source that supplies an excitation current to the electromagnet, a switching element that controls on / off of the excitation current, and energy stored in the electromagnet when the switching element is off. An electromagnetic energy emission circuit that emits and a pulse generation means for generating a pulse signal to be supplied to the switching element;
In the electromagnetic energy emission circuit, a circuit in which a diode and a resistor having a resistance value R larger than the resistance value r are connected in series is connected in parallel to the electromagnet;
Periodically supplying the pulse signal to the switching element to cause the electromagnet to generate an oscillating magnetic field having the period of the pulse signal;
Oscillating magnetic field generator. The first switching element is composed of an insulated gate element, and the pulse generation means includes a first timing generator for determining a cycle of a switching pulse supplied to the switching element, and a high level side of the switching pulse. A second timing generator defining a width of
The oscillating magnetic field generator according to claim 1. An electromagnet drive circuit for driving an electromagnet having an inductance L and a resistance value r;
A terminal for connecting to a DC power source for supplying an excitation current to the electromagnet; a switching element for controlling on / off of the excitation current; and an electromagnetic energy release for releasing energy stored in the electromagnet when the switching element is off. A circuit and pulse generation means for generating a pulse signal to be supplied to the switching element, wherein the electromagnetic energy emission circuit includes a diode and a resistor having a resistance value R larger than the resistance value r connected in series. A circuit connected to the electromagnet in parallel, and periodically supplying the pulse signal to the switching element, thereby causing the electromagnet to generate an oscillating magnetic field having the period of the pulse signal;
Electromagnet drive circuit. 3. The oscillating magnetic field generator according to claim 1 or 2, a parts receiving part for inserting a large number of parts, a parts transfer path for moving parts inserted from the parts receiving part while being aligned, and the parts transferring path A parts supply unit for supplying the parts that have been transferred one by one, and a vibration table that mounts the parts transfer path and receives a vibration magnetic field from the vibration magnetic field generator and applies vibration to the parts transfer path. A main body having;
Applying the vibration to the parts transfer path by an oscillating magnetic field generated by the oscillating magnetic field generator, thereby moving the parts while being aligned along the parts transfer path;
Parts feeder. A power supply for supplying power to the main body and the oscillating magnetic field generator;
The parts feeder according to claim 4. Adjustable to match the frequency of the oscillating magnetic field to the natural frequency of its own vibration mechanism;
The parts feeder according to claim 4 or 5. A parts feeder according to any one of claims 4 to 6 is provided;
Automatic immunoassay device.

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