JP7402770B2 - Intermittent relay for level crossing warning lights - Google Patents

Description

The present invention relates to an intermittent relay for a warning light at a level crossing, and more particularly to a technique that is effective when used in an intermittent relay for a warning light constituting a level crossing safety device.

Railway level crossings are equipped with level crossing safety equipment that includes level crossing barriers, level crossing warning devices (acoustic generators and level crossing warning lights), and a level crossing control device that controls these devices.
The level crossing control device starts a level crossing warning when the level crossing controller on the train approach side detects a train, based on signals from a pair of level crossing controllers installed at both ends of a predetermined section across the level crossing, and When the level crossing controller passes through the detection range of the level crossing controller, the level crossing warning operation is terminated. Among these, the level crossing warning light is equipped with two lamps, and when a train approaches, it is driven to alternately blink (turn on/off) by an electronic component called an intermittent relay, which is controlled by the level crossing control device. .

Japanese Patent Application Publication No. 2004-14489 Japanese Patent Application Publication No. 2014-131391

Intermittent relays generally include an oscillator and a drive circuit having two output transistors whose outputs alternately supply current to two lamps. An example of an invention related to an intermittent relay is described in Patent Document 1, for example. The intermittent relay is inserted into a jack board housed in the level crossing equipment box, along with a relay that transmits a signal to operate other equipment such as a circuit breaker.
Conventionally, in a level crossing safety system using an FF-AIII type intermittent relay (see FIG. 5), there have been reports of an event in which a warning light dimly lights up even though the level crossing is not issuing a warning. In addition, dim lighting (slight luminescence) also occurs in DC power supply devices for warning lights, and the invention described in Patent Document 2 discloses a technique for preventing faint luminescence in DC power supply devices. .

The present inventor investigated the cause of dim lighting in a warning light operated by an FF-AIII type intermittent relay. As a result, it was found that the cause was an increase in contact resistance due to deterioration of the contact of the relay that inputs the control signal that instructs the intermittent relay to blink. The mechanism by which dim lighting occurs will be explained below.
FIG. 5 shows the circuit configuration of the FF-AIII type intermittent relay. In FIG. 5, C24 is a common terminal to which a reference voltage is applied, B24 is a positive power supply voltage terminal to which a DC voltage that is +24V higher than the voltage of common terminal C24 is applied, and RN is a terminal that responds when a train approaches. The control terminals L1+, L2+ are connected to the contact S0 of the relay which is made non-conductive by the alarm light operation control signal generated by the warning light; L1-, L2- are connected to the two lamps L1 and L2 of the alarm light. These are external terminals, and the voltage of the positive power supply voltage terminal B24 is supplied to L1+ and L2+ via the internal power supply line.

The intermittent relay includes output transistors FET1 and FET2 connected between external terminals L1- and L2- and common terminal C24, an oscillation circuit OSC that performs self-oscillation, and an oscillation signal from the oscillation circuit OSC to activate the output transistors. Control transistors TR1 and TR2 are provided to turn on and off the FET1 and FET2, and the control transistors TR1 and TR2 are turned on and off by complementary signals. In this way, by alternately turning on and off the output transistors FET1 and FET2, current is alternately passed through the two lamps L1 and L2 of the warning light, causing them to blink. Note that a power supply circuit (regulator) for generating the operating voltage of the oscillation circuit OSC is also provided in the intermittent relay, but its illustration is omitted in FIG.

In the intermittent relay with the above configuration, since enhancement type field effect transistors are used for the output transistors FET1 and FET2, the contact S0 of the relay connected to the control terminal RN deteriorates and the resistance increases, causing the control terminal RN to When the voltage increases by, for example, +1V, the gate voltages of the output transistors FET1 and FET2 are raised via the diodes D3, D1 and D3, D2. As a result, the gate-drain voltage of the output transistors FET1 and FET2 increases, and although FET1 and FET2 are almost off, a weak drain current flows, causing the warning lamps L1 and L2 to dim. It will be lit.

The present invention has been made with attention to the above-mentioned problems, and an object thereof is to provide an intermittent relay for a level crossing warning light that can prevent the level crossing warning light from dimly lighting up.
Another object of the present invention is to provide an intermittent relay for a railroad crossing warning light that has a failure detection function that detects and issues a failure by itself.

In order to solve the above problems, the present invention
A power supply terminal to which voltage from an external power supply is input, an oscillation circuit that generates a signal of a predetermined frequency, a pair of output terminals to which a pair of railroad crossing warning lights are connected, and a connection to the pair of output terminals. an output circuit having a pair of transistors that turns on and off a current flowing through the pair of lamps; a control terminal to which an external signal instructing the operation of the railroad crossing warning light is inputted via a relay contact; a control circuit that controls the output circuit according to the state of an oscillation signal from an oscillation circuit and an input signal of the control terminal, and outputs a current that causes the pair of lamps to blink alternately when a train is approaching; In the intermittent relay for level crossing warning lights equipped with
A photocoupler is provided between the control terminal and the control circuit, and the state of the input signal of the control terminal is input to the control circuit via the photocoupler.

According to the intermittent relay configured as above, the state of the input signal of the control terminal is input to the control circuit via the photocoupler, so the resistance value of the relay contact connected to the control terminal increases. Even if the voltage at the control terminal increases, the effect will not be transmitted to the control circuit, making it possible to avoid increasing the control voltage (gate voltage) of the output transistor (FET) in the output circuit. It is possible to prevent the level crossing warning light from dimly lighting up.

Preferably, the output circuit includes current detection means for detecting a current flowing through the output circuit, and detects an abnormal operation based on the current value detected by the current detection means and the state of the input signal of the control terminal. The system is configured to include a failure detection circuit that provides notification.
According to this configuration, since a failure detection circuit is provided that detects and issues an abnormality in operation, the output circuit does not pass current when the operation control signal input from the outside instructs the blinking of the warning lamp. In other words, if the lamp is not flashing, it can be detected and notified.

Further, preferably, a second photocoupler is provided between the control terminal and the failure detection circuit, and the state of the input signal of the control terminal is input to the failure detection circuit via the second photocoupler. Configure it so that
According to this configuration, the influence of contact deterioration does not affect the control (gate voltage) of the output transistor at all, and by using a photocoupler, the failure detection circuit can control the resistance value of the contact connected to the control terminal. It is possible to avoid being affected by the increase in

Furthermore, preferably, the failure detection circuit includes a relay that outputs a signal to notify the outside that an operational abnormality has been detected when the failure detection circuit detects an operational abnormality, and an external terminal to which a contact of the relay is connected,
The external terminal is provided on the front surface of a casing housing the intermittent relay, and the power supply terminal, the pair of output terminals, and the control terminal are provided on the back surface of the casing.

According to this configuration, since the external terminals (N, R) are provided on the front surface of the casing in which the intermittent relay is housed, the casing can be easily connected without changing the jack plate into which the intermittent relay is inserted. An abnormality detection signal can be taken out from the front terminals (N, R). Therefore, even if a failure detection function is installed, it will be compatible with current products and easy to replace.

According to the intermittent relay for a railroad crossing warning light according to the present invention, dim lighting of the warning light can be prevented. It can also detect and notify failures by itself. Furthermore, it has the advantage of being compatible with current products and being easy to replace.

1 is a schematic configuration diagram showing an example of a level crossing control system including a level crossing control device in which an intermittent relay according to the present invention is used. FIG. 1 is a circuit configuration diagram showing an embodiment of an intermittent relay for a railroad crossing warning light according to the present invention. FIG. 2 is a circuit configuration diagram showing the configuration of an output circuit constituting the intermittent relay of the embodiment and the connection state between a transistor of the output circuit and a photocoupler. FIG. 2 is a circuit configuration diagram showing a specific configuration example of an abnormality detection circuit provided in the intermittent relay of the embodiment. It is a figure showing the example of composition of the intermittent relay of the conventional level crossing warning light.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of a level crossing control system including a level crossing control device using an intermittent relay according to the present invention. As shown in FIG. 1, the level crossing control system includes a warning device (sound generator and level crossing warning light) 11, a barrier 12, and a level crossing control device 13 that controls these installed near the level crossing. There is.

In addition, an HC type level crossing controller 14A that detects the approach of a train and an HO type level crossing controller 14B that detects the passing of a train are installed at a predetermined distance from the level crossing, respectively, with the HC type level crossing controller 14A The detection signal (relay output) of the HO type level crossing controller 14B is transmitted to the level crossing control device 13 via cables 15A, 15B, and the internal relay is operated to drop or lift.
The intermittent relay that is the object of the present invention is inserted into a jack plate in a level crossing equipment box that constitutes the level crossing control device 13 together with a relay that transmits a signal to operate other equipment such as a circuit breaker.

FIG. 2 shows an example of the circuit configuration of an embodiment of the intermittent relay 20 according to the present invention. In addition, the elements constituting the circuit surrounded by the rectangular frame labeled 20 in FIG. 2 are mounted on a single printed wiring board, and the back side of this board has a plurality of terminals that are inserted into the jack board. It is housed in a box-shaped housing with a Furthermore, among the external terminals shown in FIG. 2, terminals N, C, and R are provided on the front surface of the housing, and the other terminals B24, C24, RN, L1+, L2+, L1-, and L2- are It is provided on the back of the casing.

As shown in FIG. 2, the intermittent relay 20 of this embodiment has output circuits 21A and 21B for supplying current to two warning lamps L1 and L2 connected to external terminals L1- and L2- to light them. , an oscillation circuit 22 that self-oscillates at a predetermined frequency, and a control circuit 23A that controls the output circuits 21A and 21B using an oscillation signal from the oscillation circuit 22 or a frequency-divided signal thereof and a signal inverted by an inverter. 23B.

In addition, the intermittent relay 20 of this embodiment includes a failure detection circuit 24 having a function of detecting a failure by itself, and power supply circuits 25A and 25B including voltage regulators that generate operating voltages for the oscillation circuit 22 and the failure detection circuit 24, respectively. , a photocoupler 26A provided between the control terminal RN and the control circuits 23A and 23B, and a photocoupler 26B provided between the control terminal RN and the failure detection circuit 24.
In this embodiment, an element Tr (B) represented by a resistance is provided at the terminals L1+, L2+ and the lamps L1, L2 assuming that non-LED type lamps L1, L2 are used. When using a lamp, the Tr(B) element is not required.

Output circuits 21A and 21B of each of the circuit blocks shown in FIG. 5 are equipped with output transistors FET1 and FET2 consisting of field effect transistors shown in FIG. It is a similar circuit.
The control circuits 23A and 23B are connected between the bipolar transistors TR1 and TR2 shown in FIG. 5 with resistors R3, R4 connected, diodes D1, D2 connected in series with resistors R3, R4 and diode D3 connected between the cathode terminals of D1, D2 and the control terminal RN. It is a similar circuit.

However, in this embodiment, the cathode terminal of the diode D3 is connected not to the control terminal RN but to the common terminal C24 via the phototransistor PT on the light receiving side of the photocoupler 26A, as shown in FIG. has been done. Note that the diode D3 may be omitted and the cathode terminals of the diodes D1 and D2 may be connected to the phototransistor PT.
As described above, if the control circuits 23A and 23B are configured to transmit the operation control signal input through the external contact S0 (see FIG. 5) via the photocoupler 26A, the contact S0 Since the influence of the increase in resistance due to deterioration does not affect the gate voltages of transistors FET1 and FET2 of output circuits 21A and 21B, lamps L1 and L2 connected to external terminals L1+, L2+, L1-, and L2- are dimly lit. It is possible to prevent the light from turning on.

Incidentally, dim lighting of the lamps L1 and L2 can be prevented by, for example, connecting the source terminals of the transistors FET1 and FET2 to the external terminal RN, in addition to the method of providing the photocoupler 26A as described above. However, doing so has the disadvantage that the current flowing through the contact S0 connected to the external terminal RN reduces the brightness when the lamps L1 and L2 are turned on.
Therefore, it is conceivable to replace the relay having contacts connected to the external terminal RN with one that can flow a larger current.

However, when replacing a relay with a larger one as described above, there is a risk that the intermittent relay in question may not be able to match the other relays on the jack board to which it is connected, or that the jack board may need to be redesigned. This may lead to an increase in costs. In contrast, according to the intermittent relay of the above embodiment, dim lighting can be prevented by adding one photocoupler and slightly changing the wiring pattern, and a significant increase in cost can be avoided.
In addition, the number of external terminals used is the same as the conventional intermittent relay shown in Figure 5, and the current flowing through the failure detection circuit 24 is considerably smaller than the current flowing through the warning lamp, so it is compatible with conventional products. This has the advantage that there is no need to change the design of the jack board.

FIG. 4 shows a specific example of the circuit configuration of the failure detection circuit 24.
The failure detection circuit 24 in this embodiment includes a current detection circuit 41 equipped with a current probe 41a such as a Rogowski coil that detects the current flowing in the output circuits 21A and 21B, and constantly monitors the current flowing in the lamp of the warning light; A signal reception detection circuit 42 is connected to the phototransistor side of the photocoupler 26B and detects the absence of the operation control signal, and a signal reception detection circuit 42 is connected to the phototransistor side of the photocoupler 26B and detects the disappearance of the operation control signal. A determination circuit 43 that determines whether a current is flowing is provided.
For the current detection circuit 41, a circuit similar to a known current detection circuit composed of, for example, an operational amplifier or a comparator can be used.

When the signal reception detection circuit 42 determines that a current of a predetermined value or more is not flowing through the warning lamp when the operation control signal indicates the approach of a train, the signal reception detection circuit 42 stops the relay drive circuit 44 that is constantly operating. to stop the excitation of the solenoid SOL of the abnormality notification relay, and operate the LED drive circuit 45 to light the abnormality notification LED 46 provided on the front of the casing of the intermittent relay 20 to notify the abnormality. . Further, when the solenoid SOL of the abnormality notification relay (abnormality R) is de-energized by the relay drive circuit 44, the solenoid SOL connected between the external terminals N and R and the terminal C (B24) shown in FIG. Contact S1 is cut off and S2 is made conductive.

With the above configuration, the signal reception detection circuit 42 transmits an abnormality detection signal via the cable connected to the external terminals N, C, and R, and sends an abnormality detection signal to an abnormality alarm installed at a remote location. It is possible to notify the equipment or monitoring device of the occurrence of an abnormality in the intermittent relay. In addition, since the external terminals N, C, and R are provided on the front of the casing in which the intermittent relay is housed, terminals N , C, and R, an abnormality detection signal can be extracted.

In addition, in addition to providing a plurality of LEDs 46 for abnormality notification, the determination circuit 43 is provided with a function to determine whether a current of a predetermined value or more is flowing through the lamp of the warning light when the operation control signal does not indicate the approach of a train. Even when such a state is detected, the abnormality notification LED 46 may be turned on and an abnormality detection signal may be sent to the outside.
Alternatively, a reset button may be provided on the front surface of the casing of the intermittent relay, and the abnormality notification LED 46 may be kept lit until the reset button is pressed. Furthermore, a timer circuit may be provided on the board of the intermittent relay so that the contact point of the abnormality notification relay automatically returns after a predetermined period of time has elapsed after conduction.

Furthermore, although the failure detection circuit 24 of the embodiment shown in FIG. 4 is provided with a photocoupler 26B, in terms of circuit operation, the voltage at the connection node N1 between the diodes D1, D2 and D3 in the circuit shown in FIG. 43, it is also possible to have a configuration in which the photocoupler 26B and the signal reception detection circuit 42 are omitted. However, in that case, the gate voltage of the output transistors FET1 and FET2 may be affected, but by providing the photocoupler 26B and the signal reception detection circuit 42 as described above, the control of the output transistors FET1 and FET2 can be completely controlled. In addition, by using the photocoupler 26B, there is an advantage that the failure detection circuit 24 is not affected by an increase in the resistance value of the contact connected to the control terminal RN.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiment, the photocoupler 26B is provided between the control terminal RN and the failure detection circuit 24, but the photocoupler 26B is omitted and the current signal of the control terminal RN is input to the failure detection circuit 24. You may also do this.

11 Level crossing warning light 12 Circuit barrier 13 Level crossing control device 14A, 14B Level crossing controller 15A, 15B Cable 20 Intermittent relay 21A, 21B Output circuit 22 Oscillator circuit 23A, 22B Control circuit 24 Failure detection circuit 25A, 25B Power supply circuit 26A, 26B Photo Coupler 41 Current detection circuit 41a Current probe 42 Signal reception detection circuit 43 Judgment circuit 44 Relay drive circuit 45 LED drive circuit 46 Abnormality notification LED

Claims (4)

A power supply terminal to which voltage from an external power supply is input, an oscillation circuit that generates a signal of a predetermined frequency, a pair of output terminals to which a pair of railroad crossing warning lights are connected, and a connection to the pair of output terminals. an output circuit having a pair of transistors that turns on and off a current flowing through the pair of lamps; a control terminal to which an external signal instructing the operation of the railroad crossing warning light is inputted via a relay contact; a control circuit that controls the output circuit according to the state of an oscillation signal from an oscillation circuit and an input signal of the control terminal, and outputs a current that causes the pair of lamps to blink alternately when a train is approaching; An intermittent relay for a railroad crossing warning light, comprising:
A photocoupler is provided between the control terminal and the control circuit, and the state of the input signal of the control terminal is input to the control circuit via the photocoupler. Intermittent relay for railroad crossing warning lights. A failure detection circuit includes a current detection means for detecting a current flowing through the output circuit, and detects and notifies an operational abnormality based on the current value detected by the current detection means and the state of the input signal of the control terminal. The intermittent relay for a railroad crossing warning light according to claim 1, further comprising: an intermittent relay for a railroad crossing warning light according to claim 1. A second photocoupler is provided between the control terminal and the failure detection circuit, and the state of the input signal of the control terminal is input to the failure detection circuit through the second photocoupler. 3. The intermittent relay for a railroad crossing warning light according to claim 2. comprising a relay that outputs a signal to notify the outside that the malfunction has been detected when the failure detection circuit detects the malfunction, and an external terminal to which the contact of the relay is connected;
Claim 2, wherein the external terminal is provided on the front surface of a casing housing the intermittent relay, and the power supply terminal, the pair of output terminals, and the control terminal are provided on the back surface of the casing. Or an intermittent relay for the level crossing warning light described in 3.

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