JP2012190701A - Timer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components of a timer equipped with a relay furthermore.SOLUTION: The timer 200 comprises a relay 20 which is switched to determine whether power or a signal is fed to a load or not, and a control unit 10 which operates with power supplied from an AC power supply 50 to perform on/off control of the relay 20. The relay 20 has a half-wave rectifier circuit D1 which performs half-wave rectification of an AC current from the AC power supply 50, an AC relay 100 to which a pulsating current subjected to half-wave rectification by the half-wave rectifier circuit D1 is input, and a switch circuit TR1 which turns the pulsating current input to the AC relay 100 on/off. The control unit 10 outputs a drive signal to the switch circuit TR1 in order to perform PWM control of the AC relay 100 in a period when power or a signal is supplied to a load.

Description

  The present invention relates to a timer including a relay.

Patent Document 1 discloses a rectifier diode that rectifies an AC current from an AC power supply, a smoothing capacitor that smoothes a current output from the rectifier diode, a relay coil that receives a current smoothed by the smoothing capacitor, And a relay driving transistor for turning on or off a current input to the timer. In Patent Document 1, the number of parts of the timer is reduced.
Patent Document 1 Japanese Patent No. 3661272

  However, further reduction in the number of parts of the timer is required. Therefore, an object of the present invention is to further reduce the number of parts of a timer including a relay.

  A timer according to the present invention is a timer including a relay unit that switches whether power or a signal is supplied to a load, and a control unit that operates by power from an AC power source and controls on / off of the relay unit. The relay unit includes a half-wave rectifier circuit that half-rectifies the alternating current from the AC power source, an AC relay that receives a half-wave rectified current by the half-wave rectifier circuit, and a pulse that is input to the AC relay. The control unit outputs a drive signal to the switch circuit in order to perform PWM control of the AC relay in a period in which power or a signal is supplied to the load.

  In one aspect of the timer according to the present invention, the half-wave rectifier circuit may input a pulsating current that has not been smoothed by the smoothing circuit to the AC relay.

  In one aspect of the timer according to the present invention, the AC relay includes a relay coil that generates a main magnetic flux by a pulsating current, a winding coil that generates a submagnetic flux that is out of phase with the main magnetic flux by the main magnetic flux, and a load and an electrical And a movable contact electrically connected to the fixed contact by an attractive force generated by a main magnetic flux and a sub magnetic flux.

  In one aspect of the timer according to the present invention, a diode connected in parallel with the relay coil and absorbing a counter electromotive force generated in the relay coil may be further provided.

  In one aspect of the timer according to the present invention, the control unit turns on the switch circuit until the current value output from the AC relay reaches the reference current value during the period in which power or a signal is supplied to the load. The AC relay may be PWM controlled by outputting a drive signal that repeats a cycle for turning off the switch circuit for a period of time.

  In one aspect of the timer according to the present invention, the control unit may perform PWM control of the AC relay based on a reference current value and a reference off period determined based on the rated voltage of the AC power supply.

  In one aspect of the timer according to the present invention, a control unit, a substrate that holds the control unit, a case that houses a relay unit that is electrically connected to the control unit via the substrate, and an alternating current between the relay unit and the control unit You may further provide the terminal which outputs the electric power from a power supply, and the external terminal which has a terminal which electrically connects a relay part and load.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

It is a figure which shows the circuit structure of the timer which concerns on this embodiment. It is a figure which shows the internal structure of the timer which concerns on this embodiment. It is a figure which shows an example of the parameter of PWM control.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a diagram illustrating a circuit configuration of a timer 200 according to the present embodiment. The timer 200 is a so-called relay built-in solid state timer, and includes a relay unit 20, a control unit 10, a DIP switch 30, and a pulse generation unit 40.

  The relay unit 20 switches whether power or a signal is supplied to a load connected to the timer 200. The control unit 10 operates with electric power from the AC power supply 50 and controls the on / off of the relay unit 20.

  The control unit 10 is, for example, an IC chip, and outputs a drive signal to the transistor TR1 in order to perform PWM control of the AC relay 100 during a period in which power or a signal is supplied to a load connected to the timer 200.

  Relay unit 20 includes a diode D1, an AC relay 100, and a transistor TR1 connected in series. Furthermore, the relay unit 20 includes a diode D <b> 2 in parallel with the AC relay 100. The diode D1 is an example of a half-wave rectifier circuit, and performs single-phase half-wave rectification on the AC current from the AC power supply 50. A pulsating current half-wave rectified by the diode D1 is directly input to the AC relay 100 without passing through a smoothing circuit such as a smoothing capacitor. The transistor TR1 is an example of a switch circuit, and turns on or off the pulsating current input to the AC relay 100. A drive signal from the control unit 10 is input to the base of the transistor TR1 through the resistor R2, the resistor R3, and the capacitor C1. The resistor R3 and the capacitor C1 are elements for stably inputting a drive signal to the base of the transistor TR1. The diode D2 is connected in parallel with the relay coil of the AC relay 100 and absorbs the back electromotive force generated by the relay coil.

  The relay unit 20 further includes a resistor R1, a resistor R4, and a capacitor C2 as a current detection circuit that detects a current value output from the AC relay 100. The control unit 10 calculates the current value output from the AC relay 100 based on the voltage value at both ends of the resistor R1.

  The controller 10 turns on the transistor TR1 until the current value output from the AC relay 100 reaches the reference current value in a period in which power or a signal is supplied to the load connected to the timer 200. The AC relay 100 is PWM-controlled by outputting a drive signal that repeats the cycle of turning off TR1.

  The dip switch 30 is a switch for setting a time range and an operation mode indicating a period during which power or a signal is supplied to a load connected to the timer 200. The pulse generator 40 outputs a pulse having a predetermined period. The controller 10 has a counter that counts the pulses generated by the pulse generator 40. The control unit 10 counts up for each number of pulses corresponding to the time range set by the DIP switch 30. Further, the control unit 10 outputs a drive signal to the transistor TR1, that is, a period during which power or a signal is supplied to the load, based on the number of pulses counted according to the operation mode set by the DIP switch 30. I have control. For example, the control unit 10 operates in the first operation mode in which the AC relay 100 is turned on before counting up, that is, the driving signal is output to the transistor TR1 until counting up. Alternatively, the control unit 10 operates in the second operation mode in which the AC relay 100 is turned off after counting up, that is, the output of the drive signal to the transistor TR1 is stopped after counting up. Alternatively, the control unit 10 operates in a third operation mode that repeats the first operation mode and the second operation mode.

  The timer 200 includes a surge absorbing element SA, a resistor R10, a diode D10, a smoothing capacitor C10, a resistor R12, a light emitting diode FD1, a resistor R16, a resistor R14, a light emitting diode FD2, a transistor TR2, and a Zener diode D20.

  The surge absorbing element SA is an element for surge current protection. The resistor R10, the resistor R12, and the resistor R14 are resistors for dropping the voltage to a reference voltage necessary for driving the IC chip constituting the control unit 10. The diode D10 is a rectifier circuit that half-wave rectifies an alternating current from the alternating current power supply 50. The smoothing capacitor C10 is a smoothing circuit that smoothes the pulsating current half-wave rectified by the diode D10. The light emitting diode FD1 is a power display element indicating that the timer 200 is powered on. The light emitting diode FD2 is an element for displaying an operating state indicating that the AC relay 100 is operating, that is, that the power or signal from the timer 200 is supplied to the load. The controller 10 supplies a signal to the gate of the transistor TR2 while the drive signal is not input to the AC relay 100, and outputs a signal to the gate of the transistor TR2 while the drive signal is input to the AC relay 100. Do not supply. Thereby, according to the operating state of the AC relay 100, the light emitting diode FD2 emits light. The Zener diode D20 is an element for stably supplying a constant voltage from the AC power source to the control unit 10.

  In the present embodiment, the diode D1 directly inputs the pulsating current that is not smoothed by the smoothing circuit to the AC relay 100. That is, the timer 200 does not include a smoothing circuit between the diode D1 and the AC relay 100. When the pulsating flow that has not been smoothed by the smoothing circuit is directly input to the relay coil, the current is not stable, so that the movable contact of the relay vibrates, and so-called distortion occurs. Therefore, in this embodiment, an adverse effect caused by deleting the smoothing circuit is suppressed by using an AC relay instead of a DC relay as a relay. Thereby, according to this embodiment, generation | occurrence | production of the beat of a relay can be suppressed and the number of parts of the timer 200 can be reduced and cost can be reduced, implement | achieving the stable operation of the timer 200.

  FIG. 2 is a diagram showing the internal structure of the timer 200. The timer 200 includes an electronic circuit 120 and a case 140 that houses the AC relay 100 that is electrically connected to the electronic circuit 120. The electronic circuit 120 includes a substrate 122 on which elements such as an IC chip, an IC chip, and a light emitting diode as the control unit 10 are disposed, and a substrate 124 that is electrically connected to the substrate 122 and on which elements such as resistors are disposed. The timer 200 further includes a compatible terminal 130 that is an external terminal having a terminal 134 that outputs power from the AC power supply 50 to the AC relay 100 and the control unit 10, and a terminal 132 that electrically connects the AC relay 100 and a load. Is provided.

  The AC relay 100 includes an iron core 102, a relay coil 104, a winding coil 106, a movable piece 108, a movable contact 110, a fixed contact 112, and a yoke 114. The relay coil 104 generates a main magnetic flux by a pulsating flow directly input from the diode D1. The winding coil 106 generates a sub magnetic flux that is out of phase with the main magnetic flux by the main magnetic flux. The fixed contact 112 is electrically connected to a load via the terminal 132. The movable contact 110 is electrically connected to the fixed contact 112 by the movable piece 108 coming into contact with the iron core 102 by the attractive force generated by the main magnetic flux and the sub magnetic flux. As described above, the diode D2 is connected to the relay coil 104 in parallel. Thereby, when the current input to the relay coil 104 is turned off, an induced current due to the counter electromotive force generated in the relay coil 104 is input to the relay coil 104 via the diode D2, thereby generating a magnetic flux. As a result, during PWM control, the movable contact 110 and the fixed contact 112 can be used even when the current input to the relay coil 104 is off and even when the current input to the relay coil 104 is a pulsating flow. The suction force that can maintain the electrical connection is more reliably maintained.

  The timer 200 incorporates a number of elements constituting the timer 200 inside the case 140. On the other hand, downsizing and cost reduction of the timer 200 are required, and the small timer 200 cannot incorporate a dedicated power supply circuit for driving the relay. Therefore, it is necessary to supply power from the power source that supplies power to the IC chip of the timer 200 also to the relay. The specifications of the power supply voltage vary depending on the type of relay. If a timer that does not meet the specifications of the power supply voltage is used, a beat or the like will occur in the relay built in the timer. Therefore, the specification of the power supply voltage of the timer 200 incorporating the relay is limited by the specification of the power supply voltage of the relay. In order to eliminate such a restriction, it is conceivable that the range of power supply voltages that can be used is widened by switching the relay on control to PWM control. Such a timer may be configured to smooth the pulsating current rectified by the rectifier circuit using a smoothing circuit, and then input the smoothed current to the DC relay to perform PWM control of the driving of the DC relay. However, the electrolytic capacitor used in the smoothing circuit is relatively expensive, and depending on the specifications of the power supply voltage, it is necessary to use a large electrolytic capacitor. Therefore, the use of an electrolytic capacitor may not meet the requirements for timer downsizing or cost reduction.

  Based on the above, this embodiment provides a timer that is not equipped with a smoothing circuit that smoothes the current input to the relay coil. Here, if the smoothing circuit is simply eliminated, the current output from the rectifier circuit is a pulsating flow, so that a stable current cannot be supplied to the relay coil, and the relay cannot operate normally. Therefore, in this embodiment, an AC relay with a winding coil is used as a relay instead of a DC relay. As described above, the winding coil is a coil that generates a sub magnetic flux that is out of phase with the main magnetic flux by the main magnetic flux generated in the relay coil. By using such a winding coil, it is possible to operate the relay normally even when a stable current cannot be supplied from the power source to the relay coil. In addition, by performing PWM control of the ON control of the AC relay, it is possible to give a range to the specification of usable power supply voltage. Accordingly, since the range of power supply voltages that can be used by one timer is widened, the types of timers corresponding to the specifications of the power supply voltage can be narrowed down. Therefore, the timer parts can be shared and mass production can be realized, so that further cost reduction can be realized.

  Furthermore, the cost can be further reduced by adopting a general-purpose AC relay as an AC relay with a winding coil. However, when a general-purpose AC relay is employed, the inductance cannot be adjusted by adjusting the shape of the winding coil in order to operate the AC relay stably. Therefore, the stable operation of the AC relay may be realized by adjusting the parameters of the PWM control.

  FIG. 3 is a diagram illustrating an example of PWM control parameters according to the power supply voltage specification of the timer. The parameters for PWM control are determined in advance according to the power supply voltage specification of the timer. As described above, the control unit 10 turns on the transistor TR1 until the current value output from the AC relay 100 reaches the reference current value in the period in which power or a signal is supplied to the load, and then turns on the transistor TR1 in the reference off period. The AC relay 100 is PWM controlled by outputting a drive signal that repeats the cycle of turning off. Therefore, stable operation of the AC relay may be realized by changing the reference current value and the reference off period according to the power supply voltage specification as parameters of the PWM control.

  FIG. 3 shows an AC relay that can operate stably in each power supply voltage specification among general-purpose AC relays in which the relay coil specification and the shape of the winding coil are predetermined. Furthermore, the reference current value and the reference off period during which the AC relay employed in each power supply voltage specification can operate stably are shown. As shown in FIG. 3, for example, the reference current value may be increased as the power supply voltage is lower. Further, the reference off period may be shortened as the power supply voltage is lower. Thus, by setting the reference current value and the reference off period in advance according to the rated voltage of the power supply, even when a general-purpose AC relay is employed, the AC relay can be operated stably.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Control part 20 Relay part 30 Dip switch 40 Pulse generation part 50 AC power supply 100 AC relay 200 Timer

Claims (7)

A timer comprising a relay unit that switches whether or not to supply power or a signal to a load, and a control unit that operates with power from an AC power source and controls on or off of the relay unit,
The relay unit is
A half-wave rectifier circuit for half-wave rectifying an alternating current from the AC power source;
AC relay to which the pulsating current half-wave rectified by the half-wave rectifier circuit is input;
A switch circuit for turning on or off the pulsating current input to the AC relay,
The control unit is a timer that outputs a drive signal to the switch circuit so as to PWM-control the AC relay during a period in which power or a signal is supplied to the load.   The timer according to claim 1, wherein the half-wave rectifier circuit inputs the pulsating current that has not been smoothed by a smoothing circuit to the AC relay. The AC relay is
A relay coil for generating a main magnetic flux by the pulsating flow;
A torsion coil for generating a sub magnetic flux out of phase with the main magnetic flux by the main magnetic flux;
A fixed contact electrically connected to the load;
The timer according to claim 1, further comprising a movable contact that is electrically connected to the fixed contact by an attractive force generated by the main magnetic flux and the sub magnetic flux.   The timer according to claim 3, further comprising a diode connected in parallel with the relay coil and absorbing a counter electromotive force generated in the relay coil.   The control unit turns on the switch circuit until a current value output from the AC relay reaches a reference current value in a period in which power or a signal is supplied to the load, and then turns off the switch circuit in a reference off period. The timer according to any one of claims 1 to 4, wherein the AC relay is PWM-controlled by outputting the drive signal that repeats a cycle to be performed.   The timer according to claim 5, wherein the control unit performs PWM control on the AC relay based on the reference current value determined based on a rated voltage of the AC power supply and the reference off period. Housing the control unit, a substrate holding the control unit, and the relay unit electrically connected to the control unit via the substrate;
7. The device according to claim 1, further comprising: a terminal that outputs power from the AC power source to the relay unit and the control unit; and an external terminal that includes a terminal that electrically connects the relay unit and the load. Any one of the timers.

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