JPS6127226B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a transmitting coil and a receiving coil within a railway track, and utilizes changes in the degree of electromagnetic coupling between both coils when a train enters the detection area of both coils to detect a train. This invention relates to a train detection device that detects trains.

A transmitting coil that transmits an alternating current signal of a constant frequency and a receiving coil that receives the alternating current signal are installed on the vehicle travel path, and electromagnetic coupling between both coils occurs when a vehicle enters the detection area of both coils. A device for detecting a vehicle using a change in the level of the received signal (a change in the level of the received signal in the receiving coil) is known, for example, from Japanese Patent Publication No. 19740/1974.

However, when this type of vehicle detection device is used as a detection device for trains, especially for trains running on metal rails, it is unreliable because it is adversely affected by the rails, rainwater, etc. requires a complex configuration.

In other words, when a transmitter coil and a receiver coil are installed inside a railway track, a short circuit ring occurs between the metal rails due to the wheels, and when this short circuit occurs, the level of the received signal at the receiver coil decreases in the same way as when a train approaches. (hereinafter referred to as the reception level), a phenomenon similar to that caused by the short-circuit ring occurs due to rainwater, etc., and as a result, due to the phenomenon described above, even if there is no train, the train A presence detection signal will be output.

As a result of various experiments and research, the inventor has found that
The present invention was completed based on the discovery that the phenomenon is caused by the interlinking of the magnetic lines of force generated in the short-circuit ring with the transmitting coil and the receiving coil.

The present invention provides a train detection device in which fluctuations in the reception level due to the short circuit ring can be ignored by installing a transmitting coil and a receiving coil so that the lines of magnetic force generated in the short circuit ring do not interlink with each other. purpose.

The embodiments shown in the drawings will be described below.

In FIGS. 1 to 3, 1 and 1 are rails, and the outer side surfaces 1a of the rails 1 and 1,
A rectangular transmitting coil 2 and receiving coil 3 for a train detection device are installed in 1a. Both the coils 2 and 3 are made to have approximately the same size, and the height h direction is the same as the vertical direction of the rails 1 and 1, and the lateral direction l of both the coils 2 and 3 is the same as the rail. 1, 1 are provided facing each other so as to be parallel to each other. The coils 2 and 3 are located at a position where the centers in the height h direction coincide with the vertical centers of the rails 1 and 1, that is, the centers of the height h of the coils 2 and 3 are aligned with the rails 1 and 3. It is parallel to the treads 1', 1' of the rails 1, and is installed at a position that coincides with the center of the height H of the rails 1, 1.

The transmitting coil 2 is connected to a transmitting circuit 4 that outputs an alternating current signal of a constant frequency, and the receiving coil 3 is connected to a receiving circuit 5 that outputs a train presence detection signal when the reception level is above a predetermined value. There is.
The receiving circuit 5 includes an amplifier 6 that amplifies the signal received by the receiving coil 3, and a level detection circuit 7 such as a Schmitt circuit that outputs the detection signal when the level of the output signal is higher than a predetermined value. ing.

When both coils 2 and 3 are installed as described above, when the train is not in the detection space (above) of both coils 2 and 3, the degree of electromagnetic coupling between both coils 2 and 3 is low, so the reception level is low. , therefore, the receiving circuit 5 does not output a detection signal. However, when a train enters the detection space, the degree of electromagnetic coupling between both coils 2 and 3 increases due to the induction effect of the train, so the reception level becomes high and a detection signal is output from the reception circuit 5. Furthermore, even if the rails 1 and 1 are short-circuited due to rainwater or the like and a short-circuit ring is formed between the rails 1 and 1, the magnetic field lines of this short-circuit ring and both coils 2 and 3 do not interlink, so that between the two coils 2 and 3. The degree of electromagnetic coupling is low, so the reception level is low, and the detection circuit 5 does not output a detection signal.

Figure 4 shows that a transmitting coil and a receiving coil with a length of 4 m and a width of 15 cm are installed in the conditions shown in Figures 1 to 3 with respect to rails with a distance of 1.1 m, and a short-circuit ring is installed between the rails. This figure shows the results of measuring the rate of change in reception level in dB when both coils were simultaneously moved by the same amount in the vertical direction with respect to the rail. In the figure, the horizontal axis is the distance cm between the vertical center P of the rail and the width center of both coils.
The distance when both coils are moved upward is shown as a positive value, and the distance when both coils are moved downward is shown as a negative value. Also, curve A shows the distance between both coils.
These are the measurement results when the spacing is 1.3m, and curve B is the measurement results when the spacing is 1.6m.

In addition, when the transmitter/receiver coil is 4 m long and 15 cm wide, and the distance between both coils is 1.6 m, the freight car (Wham car)
The rate of change is about +1dB (reference value).

As is clear from FIG. 4, the farther the center of both coils in the height direction is from the center of the rail in the vertical direction, the greater the change in the reception level becomes. Therefore, it is not necessary for both coils to have their height centers exactly aligned with the vertical centers of the rails, but it is sufficient to install them so that their height centers are near the vertical centers of the rails. .

As described above, in the present invention, the transmitting coil and the receiving coil are arranged on the outer side surface of each rail so that the height direction is the same as the vertical direction of the rail, and the lateral direction is parallel to the rail. Since the vertical center of the rail and the height center of the coil coincide with each other, even if a short-circuit ring occurs between the rails, the reception level will not change due to this short-circuit ring. Trains can be detected accurately with a simple device.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of the installation state of the transmitting coil and the receiving coil, Fig. 2 is an explanatory diagram of the installation state of both coils, and Fig. 3 is a diagram showing an example of the connection state of both coils and the transmitting/receiving circuit. FIG. 4 is a diagram showing the experimental results. 1: Rail, 2: Transmitting coil, 3: Receiving coil, 4: Transmitting circuit, 5: Receiving circuit.

Claims (1)

[Claims] 1. A transmitting coil 2 and a receiving coil 3 are installed inside a railroad track, and electromagnetic interference between the coils 2 and 3 occurs when a train enters the detection space by the coils 2 and 3. In a train detection device that detects a train using a change in the degree of coupling, the transmitting coil 2 and the receiving coil 3 are connected to the outer side surfaces 1a, 1a of each rail 1, 1 in a height h direction. , 1, and facing each other so that the lateral direction l is parallel to the rails 1, 1, and the height of the vertical center of the rails 1, 1 and the height of the coils 2, 3. A train detection device characterized in that it is installed at a position that coincides with the center in the h direction. 2. The train detection device according to claim 1, wherein both the coils 2, 3 are made in a rectangular shape and extend parallel to each rail 1, 1.