JP3273558B2 - Vehicle detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a vehicle detection device.

[0002]

2. Description of the Related Art Conventionally, various types of vehicle detection devices are known. One of them is to transmit the on-board signal from the on-board antenna of the on-board device mounted on the vehicle,
The on-board signal is received by the ground guidance loop, and when the on-board signal is received, the train detection relay is operated to generate a detection signal indicating that there is a train, and when the on-board signal is not received,
2. Description of the Related Art There is known a vehicle detection device that generates a detection signal indicating that there is no vehicle by dropping a detection relay.

One of the problems of this vehicle detection system is that a fail-safe cannot be ensured because a detection relay falls when a circuit fails and a detection signal indicating that there is no train is output. .

[0004] Another problem is that it is not possible to detect a vehicle for each of various signal systems employed in an automatic train stopping device mounted on a vehicle.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fail-safe vehicle detection device.

Another object of the present invention is to provide a vehicle detecting device capable of detecting a vehicle for each signal system.

[0007]

In order to solve the above-mentioned problems, a vehicle detection device according to the present invention includes an on-board device and a ground device. The on-board device is mounted on a vehicle and transmits an on-board signal having a frequency corresponding to a signal system of the vehicle from an on-board antenna.

[0008] The ground apparatus includes a receiving coil, an inspection signal supply circuit, and an inspection signal detection circuit. The receiving coil is arranged at a position where the on-vehicle signal can be received.

The check signal supply circuit supplies a plurality of check signals according to the on-vehicle signal to the receiving coil. The check signal has a lower level than the on-vehicle signal.

[0010] The inspection signal detection circuit is supplied with a signal from the receiving coil and includes a number of frequency selection circuits according to the inspection signal. The frequency selection circuit includes a circuit that is independent of each other for the on-board signal and the corresponding inspection signal, and suppresses the inspection signal when the on-board signal is received.

In the above-described vehicle detection device according to the present invention, the ground device includes a receiving coil, and the receiving coil is provided at a position where the on-board signal can be received.
An inspection signal is supplied to the receiving coil from an inspection signal supply circuit. The ground device includes an inspection signal detection circuit, and when no vehicle is detected, only the inspection signal is received by the inspection signal detection circuit via the receiving coil. When the control signal is being received by the control signal detection circuit, a vehicle detection signal without a vehicle is obtained.

When the vehicle approaches the receiving coil, an onboard signal generated by an onboard device mounted on the vehicle is transmitted from the onboard antenna. The on-board signal is a signal having a frequency corresponding to the signal system of the vehicle. This on-vehicle signal is received by the receiving coil, and supplied to the inspection signal detection circuit together with the inspection signal.

[0013] The frequency selection circuit of the control signal detection circuit includes a circuit that suppresses the control signal when an on-board signal is received. In this case, the level of the on-vehicle signal is considerably higher than the level of the check signal, and when the above-described suppression action is applied, the component of the check signal decreases, so that the check signal cannot be detected. When the reference signal cannot be detected, a vehicle detection signal with the vehicle is output.

The on-board device transmits an on-board signal having a frequency corresponding to a signal system mounted on the vehicle from an on-board antenna. The inspection signal supply circuit of the ground device supplies a plurality of inspection signals according to the on-vehicle signal to the receiving coil. Moreover, the frequency selection circuit of the inspection signal detection circuit is independent from each other for each on-vehicle signal and corresponding inspection signal. Therefore, the inspection signal corresponding to the signal system mounted on the currently running vehicle is detected by the suppression effect, so that vehicle detection can be performed for each signal system.

[0015] As a specific mode, the receiving coil includes a first receiving coil and a second receiving coil, and the first receiving coil and the second receiving coil are inductively coupled to each other.

Further, the reference signal detection circuit may include a logic gate, and the logic gate may adopt a configuration for determining the logic of the signal output from the frequency selection circuit. According to this configuration, when a failure occurs in any of the receiving coil, the inspection signal supply circuit, and the inspection signal detection circuit, the inspection signal cannot be received, and the logic gate can make a logical determination that the vehicle is present. The logic gate is constituted by a fail-safe AND gate. Thereby, fail safe can be ensured.

[0017]

FIG. 1 is a block diagram showing the configuration of a vehicle detection device according to the present invention. As shown, the vehicle detection device according to the present invention includes an on-board device 1 and a ground device 2. The on-board device 1 is mounted on each of the n vehicles 31 to 3n, and has on-board signals Ft1, Ft2,. . . Or Ft
n is transmitted from the on-vehicle antenna 11. Vehicles 31 to 3n
Of the on-vehicle signals Ft1, Ft2,. . . Which one of Ftn and Ftn is to be transmitted is determined by the signaling system assigned to the vehicles 31 to 3n. In FIG. 1, the on-board signal Ft1 having the frequency (Ft1) is assigned to the preceding vehicle 31 and the on-board signal F having the frequency (Ftn) is assigned to the following vehicle 3n.
tn is assigned.

The ground apparatus 2 includes a receiving coil 21, an inspection signal supply circuit 22, and an inspection signal detection circuit 23. The receiving coil 21 is arranged at a position where the on-board signals of the vehicles 31 to 3n can be received. The illustrated receiving coil 21 has a structure in which a first receiving coil 211 and a second receiving coil 212 are opposed to each other, thereby causing inductive coupling.

The check signal supply circuit 22 supplies a plurality of n check signals Fc1 to Fcn to the receiving coil 21. The check signals Fc1 to Fcn have lower levels than the on-vehicle signals Ft1 to Ftn. Conversely, the levels of the on-board signals Ft1 to Ftn are considerably higher than the levels of the check signals Fc1 to Fcn. The reference signal supply circuit 22 includes a plurality of oscillators 221-2.
Inspection signals Fc1 to Fcn having different frequencies are generated by each of the oscillators 221 to 22n, and the inspection signals Fc1 to Fcn are supplied to the reception coil 21 via the addition circuit 220.

The inspection signal detection circuit 23 is provided with an on-vehicle signal Ft1.
To Ftn and the number of frequency selection circuits 231 to 23n according to the number of the check signals Fc1 to Fcn. The frequency selection circuits 231 to 23n are independent of each other on-vehicle signals Ft1 to Ftn and corresponding check signals Fc1 to Fcn. Further, the frequency selection circuits 231 to 23n output the on-vehicle signal Ft1.
To Ftn to suppress the inspection signals Fc1 to Fcn.

In the illustrated embodiment, each of the frequency selection circuits 231 to 23n includes an on-board signal Ft1 to Ft.
and a limiter 52, a band-pass filter 53 that passes the inspection signals Fc1 to Fcn, a voltage detection circuit 54, an amplifier 55, and the like. Outputs of the frequency selection circuits 231 to 23n are supplied to relays 251 to 25n.

In the above-described vehicle detection device according to the present invention, only the inspection signals Fc1 to Fcn are received by the inspection signal detection circuit 23 via the receiving coil 21 when the vehicles 31 to 3n are not detected. On-board signals Ft1 to Ft
When tn is not received and only the inspection signals Fc1 to Fcn are received by the inspection signal detection circuit 23,
A vehicle detection signal without a vehicle is obtained.

For example, focusing on the inspection signal Fc1, the inspection signal Fc1 is taken in from the receiving coil 21 to the frequency selection circuit 231. The inspection signal Fc1 passes through the band-pass filter 51, passes through the limiter 52, and further passes through the band-pass filter 53. The level is verified by the voltage detection circuit 54, and is amplified by the amplifier 55. The amplified output is supplied to the relay 251, and the relay 251 is excited. Excitation of relay 251 corresponds to without a vehicle. Similar operations are performed for other on-vehicle signals Ft2 to Ftn, check signals Fc2 to Fcn, and relays 252 to 25n.

When the vehicles 31 to 3n approach the receiving coil 21, the onboard signals Ft1 to Ft1 transmitted from the onboard antenna 11 are transmitted.
Ftn is received by the receiving coil 21. The in-vehicle signals Ft1 to Ftn and the inspection signals Fc1 to Fcn received in this way are input to the inspection signal detection circuit 23. Onboard signals Ft1 to Ftn and checking signals Fc1 to Fc
cn is extracted by the band-pass filter 51 in each of the frequency selection circuits 231 to 23n,
It is supplied to a limiter 52.

In the limiter 52, the on-vehicle signals Ft1 to Ft
n suppresses the check signals Fc1 to Fcn. Here, the level of the on-vehicle signals Ft1 to Ftn is the reference signal Fc1.
To Fcn, the components of the inspection signals Fc1 to Fcn decrease due to the suppression effect, and the limiter 52 does not output the inspection signals Fc1 to Fcn.
Therefore, in the subsequent band-pass filter 53,
The reference signals Fc1 to Fcn cannot be extracted. For this reason, the relays 251 to 25n fall, and the "vehicle is present"
Is obtained.

For example, focusing on the preceding vehicle 31, the frequency selection circuit 231 includes an on-board signal Ft1 and
The reference signal Fc1 is input. After the on-vehicle signal Ft1 and the inspection signal Fc1 are extracted by the band-pass filter 51, they are supplied to the limiter 52, where the limiter 52 receives a suppression effect. As a result, the level of the inspection signal Fc1 from the limiter 52 decreases. For this reason, the relay 251 falls, and a signal indicating that "there is a vehicle" is obtained.
Other on-vehicle signals Ft2 to Ftn, check signals Fc2 to Fcn
The same operation is performed for the relays 252 to 25n.

Here, the frequency selection circuits 231 to 23n of the inspection signal detection circuit 23 are independent of each other on-vehicle signals Ft1 to Ftn and the corresponding inspection signals Fc1 to Fcn. Therefore, when the vehicles 31 to 3n are traveling and the on-board antenna 11 of the on-vehicle device 1 is coupled to the receiving coil 21, the frequency selection corresponding to the signal system mounted on the currently traveling vehicles 31 to 3n. In the circuits 231 to 23n, the output of the check signals Fc1 to Fcn disappears, so that vehicle detection can be performed for each signal system.

In the embodiment, the inspection signal detection circuit 23 includes a logic gate 24. The logic gate 24 makes a logical decision on the signals output from the frequency selection circuits 231 to 23n. Logic gate 24 is usually formed of an AND gate. Frequency selection circuits 231 to 231 of the inspection signal detection circuit 23
If none of 23n detects a vehicle, and the frequency selection circuits 231 to 23n extract all of the inspection signals Fc1 to Fcn, the output of the logic gate 24 constituted by an AND gate has a logic value of 1. Become. This corresponds to without a vehicle.

However, the frequency selection circuits 231 to 23n
, The output of the logic gate 24 has the logic value 0. Therefore, the presence or absence of a vehicle can be detected from the output of the logic gate 24.

If a failure occurs in any of the receiving coil 21, the inspection signal supply circuit 22, or the inspection signal detection circuit 23, the system in which the circuit failure has occurred cannot receive the inspection signals Fc1 to Fcn. , Logic gate 2
The output of 4 has a logical value of 0. This state corresponds to the presence of a vehicle. Therefore, it is fail safe.

In the embodiment, a relay 26 is provided after the logic gate 24. When the vehicle 3 is not detected, the output of the logic gate 24 has the logic value 1 and the relay 26 is energized, but the output of the logic gate 24 has the logic value 0 and the relay 26 (Excitation). The relay 26 also falls (non-excited) when any of the inspection signals Fc1 to Fcn cannot be received due to vehicle detection, and is therefore fail-safe against circuit failure.

The logic gate 24 is constituted by a fail-safe AND gate. Such AND gates are disclosed, for example, in JP-B-45-29045 and JP-B-48-307.
No. 7, for example. As a result, a higher fail-safe can be ensured. When the vehicle detection which specified the signal system is not performed, the relay 25
1 to 25n can be omitted.

In the above description, an example using the relays 251 to 25n has been shown for the purpose of understanding the invention. However, it goes without saying that other circuit elements having the same function as the relays can be used.

[0034]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a vehicle detection device capable of detecting a vehicle for each signal system. (B) A fail-safe vehicle detection device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle detection device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 On-board apparatus 11 On-board antenna 2 Ground equipment 21 Inspection coil 22 Inspection signal supply circuit 23 Inspection signal detection circuit 231 to 23n Frequency selection circuit 3 Vehicle 4 Track Ft1 to Ftn On-board signal Fc1 to Fcn Inspection signal

Claims (2)

(57) [Claims] 1. A vehicle detection device including an on-vehicle device and a ground device, wherein the on-vehicle device is mounted on a vehicle and transmits an on-vehicle signal having a frequency corresponding to a signal system of the vehicle to an on-vehicle antenna. The ground device, a receiving coil, an inspection signal supply circuit,
An inspection signal detection circuit, wherein the reception coil is arranged at a position where the on-vehicle signal can be received, and the inspection signal supply circuit receives the plurality of inspection signals according to the on-vehicle signal. Supplied to a coil, the inspection signal is at a lower level than the on-vehicle signal, and the inspection signal detection circuit is supplied with a signal from the receiving coil, and includes a number of frequency selection circuits according to the inspection signal, The vehicle detection device, wherein the frequency selection circuit includes a circuit that is independent from each other for the on-board signal and the corresponding inspection signal, and suppresses the inspection signal when the on-board signal is received. 2. A ground device for a vehicle detection device, comprising: a reception coil, a check signal supply circuit, and a check signal detection circuit, wherein the reception coil is mounted on a vehicle transmitted from a vehicle antenna of the vehicle. The inspection signal supply circuit supplies a plurality of inspection signals according to the on-vehicle signal to the receiving coil, and the inspection signal is at a lower level than the on-vehicle signal. Wherein the inspection signal detection circuit is supplied with a signal from the receiving coil, and includes a number of frequency selection circuits according to the inspection signal, wherein the frequency selection circuit is provided for each of the on-vehicle signal and the corresponding inspection signal. A ground apparatus for a vehicle detection apparatus, comprising: a circuit independent of each other and configured to suppress the check signal when the on-vehicle signal is received.