JP2011210687A - Slow release relay circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a fail-safe slow release relay circuit stable in a slow release time.SOLUTION: The slow release relay circuit includes: a switch circuit 30 which is series-connected to a coil R of a relay 50 and carries out conduction/cut-off switching of a coil feed circuit 55; a storage circuit 20 which is parallel-connected to the coil R and the switch circuit 30 and charged by feeding to the feed circuit 55 from outside, and in which discharge after break of external feeding is carried out via the coil R and the switch circuit 30; and a charge-discharge circuit which is parallel-connected to the coil R and the switch circuit 30 and charged by external feeding, and in which discharge after break of external feeding is carried out by bypassing the coil R and the switch circuit 30. The switch circuit 30 switches conduction/cut-off of the feed circuit 55 corresponding to a level of a charging voltage of the charge-discharge circuit 10. Capacity C2 of the storage circuit 20 is larger than capacity C1 of the charge-discharge circuit 10, and a relay operation retainable time after break of external power feeding is longer than a conductive state maintaining time of the feed circuit 55 after break of external power feeding.

Description

  The present invention relates to a slow release relay circuit used for control of railway signals, railroad crossings, and the like. More specifically, the relay operates when a DC voltage is applied, and the slow release time elapses when the application of the DC voltage is cut off. The present invention relates to a slow release relay circuit in which a relay is restored later, and more particularly to a slow release relay circuit in which a slow release time is determined based on a discharge characteristic from a capacitor.

  The slow release relay circuit (see, for example, Non-Patent Document 1 and FIG. 5) is a type that determines the slow release time of the relay using the discharge time of the capacitor by the CR circuit. The charging / discharging circuit C3, R3 in which the charging / discharging resistor R3 and the large-capacitance capacitor C3 are connected in series is a combined circuit, and the coil R of the relay 50 and the charging / discharging circuits C3, R3 are in parallel. Charging / discharging circuits C3 and R3 are connected to the power supply path 55 of the coil R of the relay 50. In such a slow release relay circuit, when the switch SW is turned on and the DC voltage 24V is applied from the pair of power supply lines B24 and C24, the relay 50 operates to raise the relay contact, and the charge / discharge resistance R3 is set. The large-capacitance capacitor C3 is charged through this.

  When the switch SW is turned off and the application of the DC voltage 24V is stopped, the large-capacitance capacitor C3 is discharged through the charging / discharging resistor R3, the power supply path 55, and the coil R. However, when the discharge current becomes small and the excitation of the coil R becomes insufficient, the relay 50 is restored and the relay contact drops. That is, the relay 50 recovers when the discharge voltage of the large-capacitance capacitor C3 falls below the recovery voltage of the relay 50. The time from when the switch SW is turned off until the relay 50 is restored is the slow release time (or the slow release time), and the discharge characteristics by the large-capacitance capacitor C3, the charge / discharge resistor R3, and the coil R of the relay 50. And the recovery voltage of the relay 50.

Published by Japan Railway Electrical Engineering Association, “Detailed information on railroad crossing safety equipment”, pages 291-293, May 31, 2007

  When such a slow release relay is used for a railway signal, a long time of several seconds to several tens of seconds is required as a slow release time. Therefore, the capacitor C3 for setting the time element needs to have a large capacity such as an electrolytic capacitor. However, such a large-capacitance capacitor C3 is generally not excellent in capacitance characteristics related to temperature changes and changes with time. In addition, since the operation of the relay 50 is held by the discharge voltage of the large-capacitance capacitor C3, the coil R of the relay 50 is included in the discharge path of the large-capacitance capacitor C3. . And, since the recovery operation time of the relay is determined by the magnitude relationship between the recovery voltage of the relay and the discharge voltage curve of the capacitor, and the recovery operation time becomes a slow release time, the temperature recovery of the relay recovery voltage and the capacitor capacity The release time tends to fluctuate under the influence of

Even if the slow release time fluctuates and the fluctuation amount is large, the slow release relay can be used as long as the fluctuation range is within the upper and lower limits of the required specifications.
However, if the variation in the slow release time is large, the initial setting must be performed in anticipation of the maximum variation, so that burdens such as part selection and adjustment before shipment are heavy. In addition, it is difficult to meet the stricter requirements, and it is not possible to appeal high quality exceeding the requirements.
Therefore, it is an issue to improve the slow release relay circuit so that the slow release time is stable, but fail safeness is indispensable in the slow release relay circuit incorporated in the railway equipment, so a new mode that satisfies that condition is also new. A slow release relay circuit must be realized.

  The slow-release relay circuit of the present invention (Solution 1) was devised to solve such a problem, and is connected in series to a coil of a relay to switch conduction of the coil feeding path. An electric circuit switching circuit, which is connected in parallel to the coil and the electric circuit switching circuit, is charged by external power feeding to the power feeding path, and discharge after the external power feeding is interrupted is performed via the coil and the electric circuit switching circuit. A storage circuit; and a charge / discharge circuit connected in parallel to the coil and the electric circuit switching circuit and charged by the external power supply, and discharging after the external power supply is interrupted bypasses the coil and the electric circuit switching circuit. A slow-release relay circuit provided, wherein the electric circuit switching circuit switches on and off of the power feeding path according to the level of the charging voltage of the charging / discharging circuit, and the capacity of the power storage circuit is Wherein the operating holding-time of the relay after disruption of the greater than the capacity of KiTakashi discharge circuit external power supply is longer than the conduction state holding time of the feeding path after disconnection of the external power supply.

  Further, the slow release relay circuit of the present invention is (Solution means 2), which is the slow release relay circuit of the above-mentioned solution means 1, wherein both the storage circuit and the charge / discharge circuit are charged through a charge resistor in the capacity portion. A backflow prevention member for preventing discharge from the power storage circuit to the charge / discharge circuit is interposed between the two resistors.

  Further, the slow release relay circuit of the present invention is (Solving means 3), which is the slow release relay circuit of the above solving means 1 and 2, wherein the charging resistance of the charging / discharging circuit is prevented from discharging via the charging resistance. A backflow prevention member is provided, and the charge / discharge circuit discharges through a discharge resistor different from the charge resistor.

  In such a slow release relay circuit of the present invention (Solution 1), switching of the relay operation state is left to the electric circuit switching circuit, and time control, that is, a long / short decision of the slow release time is left to the charge / discharge circuit. Therefore, the large-capacity storage circuit is dedicated to maintaining the operation of the relay. Since it is sufficient that the relay operation holdable time is longer than the conduction state maintaining time of the power supply path of the relay coil, that is, the slow release time, the power storage circuit is released from the requirement of discharge accuracy. Also, the relay is freed from the requirement of the recovery voltage accuracy. Furthermore, since the capacity of the charge / discharge circuit is small, the range of member selection is widened, and the circuit can be configured using members having good characteristics without much cost. As a result, the slow release time is stabilized.

Moreover, since the only current that maintains the operation of the relay after disconnection of the external power supply is the discharge from the storage circuit, unless the discharge is forcibly blocked by the circuit switching circuit, the relay operation holding time based on the discharge of the storage circuit has elapsed. The relay must be restored. For this reason, even when a failure occurs in which a part of the circuit is broken and the circuit switching circuit is not turned off while the circuit is on, the relay is always restored, so that the fail-safe property necessary for the railway facilities is ensured.
Therefore, according to the present invention, a fail-safe slow release relay circuit with a stable slow release time can be realized.

Moreover, in the slow release relay circuit of the present invention (solution means 2), it is possible to easily prevent an undesired influence from the storage circuit to the charge / discharge circuit.
Furthermore, in the slow release relay circuit of the present invention (Solution means 3), the charge / discharge circuit can be realized by a simple analog passive circuit.

1 is a circuit diagram of a slow release relay circuit according to Embodiment 1 of the present invention. It is operation | movement explanatory drawing at the time of ON. It is operation | movement explanatory drawing at the time of OFF. It is a circuit diagram of a slow release relay circuit about Example 2 of the present invention. It is a circuit diagram of the conventional slow release relay circuit.

About the slow release relay circuit of such this invention, the specific form for implementing this is demonstrated by the following Examples 1-2.
The embodiment 1 shown in FIGS. 1 to 3 embodies all the above-described solving means 1 to 3 (claims 1 to 3 at the beginning of the application), and the embodiment 2 shown in FIG. It is a modification.

  A specific configuration of the slow release relay circuit according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram thereof.

This slow release relay circuit includes a charge / discharge circuit 10, a power storage circuit 20, an electric circuit switching circuit 30, and a relay 50.
The relay 50 may be the same as that of the conventional circuit, and the feeding path 55 of the coil R is connected to the feeding line pair B24 and C24 for external feeding through the switch SW.

  In the circuit switching circuit 30, a switching element Q1 made of a p-channel enhancement type transistor, which is a MOS FET with a small leakage current and stops the drain current when the gate voltage drops, is adopted as the switching member, and the drain of the switching element Q1 Are connected to the positive power supply line B24 and the switch SW side, the source of the switching element Q1 is connected to the negative power supply line C24, and the gate of the switching element Q1 receives the discharge voltage of the charge / discharge circuit 10 to be described later. The switching element Q1 is inserted in the power supply path 55 in a form connected to the movable terminal of the discharge resistor VR1. As a result, the electric circuit switching circuit 30 is connected in series to the coil R of the relay 50, and performs conduction interruption switching of the power supply path 55 of the coil R.

  The storage circuit 20 includes a charge / discharge resistor R2 having a resistance value of, for example, about 390Ω, a large-capacity aluminum electrolytic capacitor C2 having a capacity of, for example, about 6700 μF, and a Zener diode Z2 that is not essential and is appropriately added. Such charge / discharge resistor R2 and large-capacitance capacitor C2 are generally comparable to the conventional charge / discharge resistor R3 and large-capacitance capacitor C3 described above. One end of the charge / discharge resistor R2 is connected to the power supply path 55 between the switch SW and the coil R, and the other end of the charge / discharge resistor R2 is connected to one end of the large-capacitance capacitor C2. The end is connected to the power supply line C24, and the storage circuit 20 is connected in parallel to the coil R and the electric circuit switching circuit 30. In addition, the Zener diode Z2 has a cathode connected to one end side of the large-capacitance capacitor C2 and an anode connected to the power supply line C24 to stabilize the charging voltage of the large-capacitance capacitor C2.

  The charging / discharging circuit 10 includes a charging resistor R1 having a resistance value of, for example, about 1 KΩ, a diode D1 attached to the charging resistor R1 as a backflow prevention member for preventing discharge through the charging resistor R1, a pair of fixed terminals, and one movable terminal A discharge resistor VR1 having a terminal and a resistance value between the two fixed terminals of, for example, about 500 KΩ, a film capacitor C1 having a small capacity of, for example, about 20 μF, and having small temperature fluctuations and aging, and is appropriately added. Zener diode Z1 to be provided. One end of the charging resistor R1 is connected to the power supply path 55 between the switch SW, the coil R, and the charging / discharging resistor R2, and the other end of the charging resistor R1 and the anode of the diode D1 are connected to each other. One end of the small-capacitance capacitor C1 is connected, the other end of the small-capacitance capacitor C1 is connected to the power supply line C24, and the charge / discharge circuit 10 is connected in parallel to the coil R and the electric circuit switching circuit 30.

  Also, one of the fixed terminals of the discharge resistor VR1 is connected to one end of the small capacitor C1, and the other is connected to the power supply line C24 together with the other end of the small capacitor C1, so that the charge / discharge circuit 10 is separate from the charge resistor R1. It discharges through the discharge resistor VR1. Further, the Zener diode Z1 has a cathode connected to one end of the small capacitor C1 and an anode connected to the power supply line C24 together with the other end of the small capacitor C1 to stabilize the charging voltage of the small capacitor C1. It has become. In addition, since the movable terminal of the discharge resistor VR1 is connected to the gate of the switching element Q1 as described above, the electric circuit switching circuit 30 switches the conduction of the power supply path 55 according to the level of the charging voltage of the charging / discharging circuit 10. In addition, the slow release time can be adjusted by operating the movable terminal of the discharge resistor VR1.

  Further, regarding the relationship between the charging / discharging circuit 10 and the storage circuit 20, a diode D2 is interposed between the charging / discharging resistor R2 and the charging resistor R1 as a backflow blocking member that blocks discharge from the storage circuit 20 to the charging / discharging circuit 10. Specifically, the anode of the diode D2 is connected to the connection point between the charging resistor R1 and switching, and the cathode of the diode D2 is connected to the connection point between the charging / discharging resistor R2 and the coil R. . Further, as described above, since the capacity of the large-capacitance capacitor C2 is larger than the capacity of the small-capacitance capacitor C1, the operation holdable time of the relay 50 after disconnection of the external power supply of the DC voltage 24V through the pair of power supply lines B24 and C24 is DC. It is longer than the conduction state maintaining time of the power supply path 55 after the external power supply with a voltage of 24 V is interrupted. Note that the length is determined depending on the discharge time constant based on the capacitance values C1, C2 and the resistance values VR1, R2, R.

  The use mode and operation of the slow release relay circuit of the first embodiment will be described with reference to the drawings. FIG. 2 is an explanatory diagram of the operation at the time of on, and FIG. 3 is an explanatory diagram of the operation at the time of off.

  For example, when the switch SW composed of contact points of an alarm relay is turned on and becomes conductive (see FIG. 2), a DC voltage 24V is directly applied to the charge / discharge circuit 10 from the pair of power supply lines B24 and C24. At the same time, the DC voltage 24V is applied to the power storage circuit 20 via the diode D2, and is further applied to the series circuit of the coil R of the relay 50 and the switching element Q1.

  In the charging / discharging circuit 10, a current Ia flows through the charging resistor R1 and the diode D1, and the current Ia is divided into currents Ib and Ic at the connection point between the discharging resistor VR1 and the small-capacitance capacitor C1, and the current Ib is The small capacitor C1 flows into the small capacitor C1 and is charged, and the current Ic flows through the discharge resistor VR1. At this time, the voltage applied to the discharge resistor VR1 is transmitted from the movable terminal to the gate of the switching element Q1. In this way, in the charging / discharging circuit 10 at the time of ON, the small-capacitance capacitor C1 which is a capacity part of the charging / discharging circuit 10 is charged by the external power supply from the power supply line B24 to the power supply path 55 via the charging resistor R1.

In the storage circuit 20, a current Id flows through the charge / discharge resistor R2, and the current Id flows into the large-capacitance capacitor C2 to charge the large-capacity capacitor C2. In this way, in the on-state storage circuit 20, the large-capacitance capacitor C2 that is the capacity unit of the storage circuit 20 is charged by external power supply from the power supply line B24 to the power supply path 55 via the charge / discharge resistor R2.
Further, in the electric circuit switching circuit 30, the switching element Q1 receiving at the gate the voltage of the movable terminal of the discharge resistor VR1 of the charge / discharge circuit 10 described above is turned on, and the power supply path 55 becomes conductive. Therefore, a current Ie flows between the coil R of the relay 50 and the source and drain of the switching element Q1, and the relay 50 is operated by this current Ie to raise the relay contact.

Then, when the switch SW is switched from the ON state to the OFF state and is cut off (see FIG. 3), the external power supply from the power supply line pair B24, C24 is cut off, and the charge / discharge circuit is disconnected after the external power supply is cut off. 10 and the storage circuit 20 are also discharged.
In the storage circuit 20, the large-capacitance capacitor C2 is discharged, and the discharge current Ig flows through the charge / discharge resistor R2 in the opposite direction to the charge current Id, and after passing through the charge / discharge resistor R2, the diode D2 Is prevented from flowing toward the charge / discharge circuit 10, and therefore flows exclusively through the coil R of the relay 50 and the switching element Q <b> 1.

Further, in the charging / discharging circuit 10, the small capacitor C1 is discharged, but the discharge current If is prevented from flowing toward the charging resistor R1 by the diode D1, so that the coil R and the switching element ahead of it are prevented. It bypasses Q1 and flows exclusively through the discharge resistor VR1. Then, the applied voltage of the discharge resistor VR1 is maintained for a while by the discharge current If.
Further, in the electric circuit switching circuit 30, while the voltage applied to the discharge resistor VR1 exceeds the ON voltage of the switching device Q1, the switching device Q1 having the gate voltage as the gate voltage continues to be turned on, and the voltage applied to the discharge resistor VR1 is switched. When the voltage is lower than the on-voltage of the element Q1, the switching element Q1 is turned off and the power supply path 55 is interrupted.

  As described above, the operation holdable time of the relay 50 after disconnection of the external power supply of the DC voltage 24V via the power supply line pair B24, C24 is maintained. Since the time constant of the discharge current If in the charge / discharge circuit 10 and the time constant of the discharge current Ig in the storage circuit 20 and the relay 50 are set in advance so as to be longer than the In addition, the switching element Q1 is turned off due to the decrease in the discharge current If, and thereby the power supply path 55 is cut off and the discharge current Ig is stopped. Therefore, the relay 50 is restored and the relay contact is dropped.

  Thus, in a normal state with no failure, the slow release time is determined by the CR time constant based on the small-capacitance capacitor C1 and the discharge resistor VR1, and a capacitive element having good characteristics such as a film capacitor is used for the small-capacitance capacitor C1. Since the release time is stable. Further, since the switching element Q1 whose gate is connected to the discharge resistor VR1 employs an FET with a small leakage current, its influence is negligibly small. Further, since the Zener diode Z1 is attached to the small-capacitance capacitor C1, and the Zener diode Z2 is attached to the large-capacitance capacitor C2, the influence due to the fluctuation of the DC voltage 24V applied through the pair of feeder lines B24 and C24. Is also suppressed small. Therefore, the slow release time is further stabilized. Since the large-capacitance capacitor C2 maintains the charged state during discharging, the charging time is short thereafter.

On the other hand, when this slow release relay circuit is used in the railway field at the time of failure, the current Id does not flow in a state where the switching element Q1 is not turned on due to some failure, so the relay 50 does not operate and the relay Since the contact does not rise, fail-safety is ensured.
On the other hand, when the switching element Q1 is not turned off while being turned on due to a failure, this is the worst state, but in this state, the power supply path 55 continues to be conducted.

Then, since neither the electric circuit switching circuit 30 nor the control charge / discharge circuit 10 affects the operation of the relay 50, this slow release relay circuit uses a series connection circuit of the charge / discharge resistor R2 and the large-capacitance capacitor C2 as a relay 50. Equivalent to a circuit that is simply combined with This equivalent circuit is similar to the conventional slow release relay circuit, and the difference from the conventional product is that the operation holding time of the relay 50 by the discharge current Ig from the large-capacitance capacitor C2 is the operation of the relay 50 after the external power supply is cut off. Since the holding time is reached, the slow release time is only longer than normal.
For this reason, in this slow release relay circuit, fail-safety is ensured even in a failure state in which the switching element Q1 is not turned off while being turned on.

  As described above, in the slow release relay circuit of the present invention, the charge / discharge circuit 10 with relatively high accuracy functions as the first slow release element circuit during normal operation, and the reliable storage circuit 20 operates in the event of a failure. Since it functions as a second slow release element circuit, fail-safe property is sufficiently ensured.

  The difference between the slow release relay circuit of the present invention whose circuit diagram is shown in FIG. 4 and that of the first embodiment is that a comparator 34 is added to the electric circuit switching circuit 30.

The comparator 34 is inserted and connected to the gate line of the switching element Q1, the discharge voltage of the charge / discharge circuit 10 is compared with a predetermined reference voltage, and the switching element Q1 is turned on / off according to the magnitude of both voltages. It is supposed to be.
In general, the temperature characteristic of the circuit using the comparator 34 is superior to the temperature characteristic of the gate ON voltage of the switching element Q1, so that the fluctuation of the slow release time with respect to the temperature change is suppressed, and the accuracy of the timepiece is improved. .
In addition, the fail-safe property is maintained even in the circuit using the comparator 34.

[Others]
The discharge resistor VR1 is not limited to the variable resistor described above, and may be a circuit that switches a resistance value by combining a plurality of resistors and a switching circuit.

  The slow release relay circuit of the present invention is frequently used for the control of special signal light emitters and the control of railroad crossing breakers, but the slow release time can be set even for other railway facilities that require fail-safety. It can be used for any application purpose within the scope.

10 ... Charge / discharge circuit (first elementary circuit during normal release),
R1 ... Charging resistor, C1 ... Small capacitance capacitor, VR1 ... Discharge resistor,
20: Storage circuit (second slow release elementary circuit at the time of failure),
R2: Charge / discharge resistance, C2: Large capacity capacitor,
30 ... Electric circuit switching circuit, 34 ... Comparator, Q1 ... Switching element,
50 ... Relay, 55 ... Feeding path, R ... Coil,
R3 ... Charge / discharge resistance, C3 ... Large capacity capacitor

Claims (3)

  An electric circuit switching circuit that is connected in series to the coil of the relay and performs switching on and off of the power supply path of the coil, and is connected in parallel to the coil and the electric circuit switching circuit, and is charged by external power supply to the power supply path. The discharge after the interruption of the external power supply is a storage circuit that is connected via the coil and the electric circuit switching circuit, and is connected in parallel to the coil and the electric circuit switching circuit, and is charged by the external power supply, and after the external power supply is interrupted A slow-release relay circuit including a charge / discharge circuit that bypasses the coil and the electric circuit switching circuit, and the electric circuit switching circuit responds to a level of a charging voltage of the charge / discharge circuit. Switching the conduction interruption of the relay, and the capacity of the storage circuit is larger than the capacity of the charge / discharge circuit, and the operation holding time of the relay after the interruption of the external power feeding is the external Yuruho relay circuit, characterized in that is longer than the conduction state holding time of the feeding path after disruption of electricity.   In both the storage circuit and the charge / discharge circuit, the capacitor portion is charged through a charging resistor, and a reverse flow blocking member for blocking discharge from the storage circuit to the charging / discharging circuit is interposed between these resistors. The slow release relay circuit according to claim 1, wherein the slow release relay circuit is inserted and connected.   The charging resistor of the charging / discharging circuit is provided with a backflow prevention member for preventing discharge through the charging resistor, and the charging / discharging circuit is discharged through a discharging resistor different from the charging resistor. The slow release relay circuit according to claim 1, wherein the release relay circuit is provided.

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