JP5030234B2 - Axle detector and axle detector - Google Patents

Description

  The present invention relates to an axle detector that detects an axle of a train traveling on a rail and an axle detector using the axle detector.

  A conventional axle detection device of this type includes an axle detector in which one transmission coil and one reception coil are combined. The transmission coil and the reception coil that constitute the axle detector are arranged in a relationship facing each other on both sides of the rail on which the train travels.

  The transmission coil is driven by an AC drive source and generates an AC magnetic field corresponding to a transmission signal. In the receiving coil, an induced voltage is generated by the AC magnetic field of the transmitting coil, and the induced voltage is output as a received signal.

  The reception voltage level of the reception signal has a property of decreasing when a train axle enters between the transmission coil and the reception coil. That is, when the wheel is positioned between the transmission coil and the reception coil, an induced current (eddy current) flows through the wheel due to the alternating magnetic field of the transmitting coil, and the alternating magnetic field generated by the induced current is changed to the alternating magnetic field of the transmitting coil. The reception voltage level output from the reception coil is lowered. Therefore, it is possible to detect that the axle is positioned on the axle detector when the received voltage level is reduced (see Patent Document 1).

  Since the conventional axle detection device detects the axle with the above-described configuration and operation, in order to improve the reliability of axle detection, when the axle is not detected and when the axle is detected It is important to be able to take a large difference in the received voltage level.

  However, since the conventional axle detection device is configured to receive the alternating magnetic field of the transmission coil with one reception coil, the voltage level of the reception signal that is the basis of axle detection is determined according to the performance of the reception coil. End up. For this reason, there is a limit to increasing the difference between the received voltage levels when the axle is not detected and when the axle is detected, and there is a risk of erroneous detection due to disturbances such as noise.

  In addition, the voltage level of the received signal itself may decrease due to noise. In particular, when noise having the same frequency as that used in the axle detector enters the axle detection system, the voltage level of the transmission signal or the reception signal is significantly reduced. Such a phenomenon is likely to occur when, for example, a system that controls the vehicle speed by changing the rotation speed of the vehicle travel motor and the frequency of the motor drive current as seen in the Shinkansen is adopted. In such a system, in the vehicle speed control process, there is a region where the frequency of the driving current of the vehicle propulsion motor coincides with the frequency used in the axle detector, and is the same as the frequency used in the axle detector. This is because noise having a frequency is likely to be generated.

Patent Document 2 discloses an axle detector that employs direct-spreading code transmission to improve noise resistance. According to this prior art, noise resistance can be improved, but a special code transmission method must be adopted for the axle detection system.
Japanese Patent Laid-Open No. 2000-6808 JP 2007-22136 A

  An object of the present invention is to provide an axle detector having a structure effective for improving noise resistance and an axle detector using the axle detector.

  Another object of the present invention is to provide an axle detector having a structure effective for improving noise resistance against noise having the same frequency as that of the axle detection system, and an axle detection device using the same. .

  Still another object of the present invention is to provide an axle detector having a structure effective for improving noise resistance while maintaining the signal transmission of the axle detection system as a simple AC transmission system, and an axle using the same. It is to provide a detection device.

  In order to solve the above-described problem, the axle detector according to the present invention includes one transmission coil, a first reception coil, and a second reception coil. That is, two receiving coils are combined with respect to one transmitting coil. The first receiving coil and the second receiving coil are arranged in the vertical direction with the coil axes aligned, and individually generate signals that respond to changes in the alternating magnetic field transmitted from the transmitting coil; and ,Output.

  As described above, in the axle detector according to the present invention, two receiving coils, that is, a first receiving coil and a second receiving coil are combined with one transmitting coil. Since the two receiving coils are arranged in the vertical direction with their coil axes aligned, each of the first receiving coil and the second receiving coil responds to a change in the alternating magnetic field transmitted from the transmitting coil. , Reception signals having the same frequency and the same phase are generated.

  Moreover, the first receiving coil and the second receiving coil individually generate signals that respond to changes in the alternating magnetic field transmitted from the transmitting coil without being connected in series or in parallel, and Output individually. Therefore, when the axle detector is configured by using the axle detector, the voltage level is increased to about twice that of the conventional one by executing addition / subtraction processing of both signals in the axle detector, thereby improving noise resistance. Improve the noise resistance against noise of the same frequency as the axle detection system, improve the noise resistance while keeping the signal transmission of the axle detection system as a simple AC transmission system, etc. A variety of useful signal processing can be performed. This point will be described more specifically in the axle detection device.

  The axle detection device includes a signal processing unit together with the axle detector, and detects the axle of a train traveling on the rail. The signal processing unit detects the axle based on the first reception signal S1 and the second reception signal S2 corresponding to the signals individually supplied from the first and second reception coils. Specifically, the axle is detected using the addition signal S5 generated by the addition process of the first reception signal S1 and the delay signal S3 obtained by delaying the second reception signal S2 by one cycle.

  As described above, in each of the first receiving coil and the second receiving coil, received signals having the same frequency and the same phase are generated in response to the change of the AC magnetic field transmitted from the transmitting coil. The first reception signal S1 and the second reception signal S2 corresponding to the signals individually supplied from the second reception coil have the same frequency and the same phase. Therefore, the voltage level of the addition signal S5 generated by the addition process of the first reception signal S1 and the delay signal S3 obtained by delaying the second reception signal S2 by one cycle has the voltage level of the first reception signal S1 and the second reception signal S2. The voltage level of the reception signal S2 and the delay signal S3 is about twice. Therefore, in the signal processing unit, by detecting the axle using the addition signal S5, the voltage level used for axle detection can be increased to about twice that of the conventional art, and noise resistance can be improved.

  Another advantage of using the delay signal S3 obtained by delaying the second reception signal S2 by one period is that the noise having the same frequency as the frequency used in the axle detection system or the noise of the adjacent frequency is This noise is extracted when it enters the detection system. In the noise extraction process, a signal processing unit constituting the axle detection device performs a subtraction process between the first reception signal S1 and the delay signal S3 obtained by delaying the second reception signal S2 by one cycle. The subtraction signal S4 generated by this subtraction process becomes a noise extraction signal. Therefore, an axle detection device with improved noise resistance against noise having the same frequency as that of the axle detection system can be obtained.

  Still another advantage of using the delay signal S3 obtained by delaying the second reception signal S2 by one cycle is that the noise having the same frequency as that used in the axle detection system or the noise of the adjacent frequency is Even when the vehicle enters the axle detection system, the voltage level used for axle detection can be maintained up to about twice the conventional level, and noise resistance can be improved. In specific signal processing, the signal processing unit detects the axle using the signal S6 generated by the subtraction process of the addition signal S5 and the subtraction signal S4. The signal processing described above cancels the influence of noise despite the presence of noise, and the voltage level of signal S6 rises to about twice the voltage level used for conventional axle detection. Therefore, noise resistance can be improved.

  Further, the axle detection device according to the present invention has an advantage that the signal processing can be performed while keeping a simple AC transmission system, instead of taking a special code transmission system.

As described above, according to the present invention, the following effects can be obtained.
(A) It is possible to provide an axle detector having a structure effective for raising the voltage level of the received signal to about twice the conventional level and improving noise resistance, and an axle detector using the axle detector.
(B) It is possible to provide an axle detector having a structure effective for improving noise resistance against noise having the same frequency as that of the axle detection system, and an axle detection device using the axle detector.
(C) To provide an axle detector having a structure effective for improving noise resistance while keeping the signal transmission of the axle detection system as a simple AC transmission system, and an axle detection device using the same. it can.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing the configuration of an axle detector incorporating an axle detector according to the present invention. Referring to the figure, the axle detector (1, 2) according to the present invention includes a transmitter 1 and a receiver 2. The transmitter 1 has one transmission coil 11, and the receiver 2 includes a first reception coil 21 and a second reception coil 22. That is, two receiving coils 21 and 22 are combined with one transmitting coil 11.

  The first and second receiving coils 21 and 22 are arranged in the vertical direction with the coil axes O1 and O2 being aligned. The first and second receiving coils 21 and 22 individually generate signals that respond to changes in the alternating magnetic field φ1 transmitted from the transmitting coil 11. And it outputs individually by the independently provided output terminals (T11, T12), (T21, T22).

  The transmission coil 11 and the first and second reception coils 21 and 22 are arranged in a relationship facing each other on both sides of the rail 4 on which the train travels. In general, the transmission coil 11 is disposed outside the rail 4, and the first and second reception coils 21 and 22 are disposed inside the rail 4. As a specific arrangement structure, a transmitter 1 in which a transmission coil 11 is housed in a case, and first and second reception coils 21 and 22 are arranged on one surface of a support plate 10 made of an iron plate having a high mechanical strength. The receiver 2 housed in the case is attached. The support plate 10 is disposed between the road bed 6 and the rail 4. The rail laying area has a construction limit, and there is a limit called a Russell limit in a snowy country. Therefore, the transmitter 1 and the receiver 2 are arranged so as to have a height within the limit.

  The transmission coil 11 is driven by an AC voltage supplied from the AC drive source 12 to the input terminals T1 and T2, and generates an AC magnetic field φ1. An induced voltage is generated in the first and second receiving coils 21 and 22 by the AC magnetic field φ1 of the transmitting coil 11, and the induced voltage is output as a coil reception signal.

  As described above, in the axle detector according to the present invention, the first and second receiving coils 21 and 22 are arranged in the vertical direction with the coil axes O1 and O2 aligned with each other. In each of the two reception coils 21 and 22, reception signals having the same frequency and the same phase are generated in response to the change of the AC magnetic field φ 1 transmitted from the transmission coil 11.

  The first and second receiving coils 21 and 22 individually generate and output individually received signals having the same frequency and the same phase in response to the change of the AC magnetic field φ1 transmitted from the transmitting coil 11. Therefore, in the axle detection device using the axle detector, the voltage level is increased to about twice that of the conventional one by executing addition / subtraction processing of both signals, and the noise resistance is improved. Perform various signal processing, such as improving the noise resistance against noise of the same frequency as the frequency of the vehicle, or improving the noise resistance while keeping the signal transmission of the axle detection system as a simple AC transmission system Can do.

  The axle detection device includes a signal processing unit 3 together with the axle detectors (1, 2), and detects an axle (wheel) 5 of a train traveling on the rail 4. The illustrated signal processing unit 3 includes a first receiving unit 31, a second receiving unit 32, a delay unit 33, and an arithmetic processing unit 34. The first receiver 31 and the second receiver 32 have a circuit configuration in which a coupling transformer, a circuit impedance adjustment attenuator, and a bandpass filter are sequentially connected, as is well known in this type of axle detection device. Have. The band-pass filter is provided for the purpose of extracting frequency components used in the axle detection system. From the first receiving unit 31, the first receiving unit having the frequency components extracted by its own band-pass filter. The signal S1 is output, and the second reception unit 32 outputs a second reception signal S2 having a frequency component extracted by its own bandpass filter. Since the first reception signal S1 and the second reception signal S2 have the same frequency, the bandpass filter provided in the first reception unit 31 and the bandpass filter provided in the second reception unit 32 have a center selection frequency. Are the same.

  The delay unit 33 delays the second reception signal S2 supplied from the second reception unit 32 by one cycle. Such a delay operation may be realized by providing a delay circuit, or may be realized by software processing in a CPU (Central Processing Unit) constituting the arithmetic processing unit 34.

  The arithmetic processing unit 34 can be configured mainly with a CPU. A representative signal that can be used is a DSP (Digital Signal Processor). Although not shown, the arithmetic processing unit 34 has an AD converter that converts the first reception signal S1 and the third reception signal S3, which are normally supplied as analog signals, into digital signals.

  Next, the axle detection operation of the axle detection device will be described with reference to FIG. The voltage level of the reception signals of the first and second reception coils 21 and 22 decreases when the train axle 5 (wheel) 5 enters between the transmission coil 11 and the first and second reception coils 21 and 22. It has the property to do. That is, in FIG. 2, when the axle 5 is located between the transmission coil 11 and the first and second reception coils 21 and 22 from t2 to t5, the AC magnetic field φ1 of the transmission coil 11 is placed on the axle 5. Thus, an induced current (eddy current) flows, and the AC magnetic field φ1 generated by the induced current acts so as to cancel the AC magnetic field φ1 of the transmission coil 11. Therefore, the first reception signal S1 output from the first reception unit 31 and the second reception output from the second reception unit 32 corresponding to the reception signals of the first and second reception coils 21 and 22. As shown in FIGS. 2A and 2B, the voltage level V1 of the signal S2 drops to almost zero voltage. Therefore, when the arithmetic processing unit 34 of the signal processing unit 3 determines that the reception voltage levels of the first reception signal S1 and the second reception signal S2 have decreased, the axle 5 is connected to the axle detector (1, 2). It is possible to detect the position.

  Here, as described above, in each of the first and second receiving coils 21 and 22, reception signals having the same frequency and the same phase are generated in response to the change of the alternating magnetic field φ 1 transmitted from the transmission coil 11. Therefore, the first reception signal S1 and the second reception signal S2 corresponding to the signals individually output from the first and second reception coils 21 and 22 are also illustrated in FIGS. 2 (a) and 2 (b). Furthermore, they have the same frequency and the same phase.

  Therefore, the addition signal S5 generated by the addition process of the first reception signal S1 and the delay signal S3 (see FIG. 2C) obtained by delaying the second reception signal S2 by one cycle is shown in FIG. As shown in FIG. 3, the voltage level is from t0 to t2 when the axle 5 does not exist, and after t6, the voltage level of the voltage level V1 of the first reception signal S1, the second reception signal S2, and the delay signal S3. The voltage level V2 is about double.

  From time t3 to time t5 when the axle 5 is positioned on the axle detector (1, 2), the addition signal S5 decreases by a voltage value V2 from a voltage level V2 that is twice the conventional level to almost zero voltage. Therefore, by detecting the axle 5 using the addition signal S5 in the signal processing unit 3, the voltage level of the signal used for axle detection can be increased to about twice that of the conventional one, and noise resistance can be improved. it can.

  As shown in FIG. 2 (e), the arithmetic processing unit 34 of the signal processing unit 3 detects the no-voltage axle detection signal from t3 to t5 when the addition signal S5 decreases by, for example, the voltage value V2. (Sd) is output.

In the present invention, the addition signal S5 is generated by the addition process of the first reception signal S1 and the delay signal S3 obtained by delaying the second reception signal S2 by one cycle, that is,
S1 + S3 = S5
Therefore, the voltage level of the addition signal S5 is determined by the delay operation of the delay signal S3 until t3 which is delayed by one cycle from t2 when the second reception signal S2 detects the axle and becomes no voltage. The voltage level V1 is maintained. Further, the addition signal S5 maintains the voltage level V1 by the delay operation of the delay signal S3 until t6, which is delayed by one cycle from t5 when the second reception signal S2 no longer detects the axle. Eventually, the addition signal S5 falls below the voltage level V1 between t2 and t6. Therefore, it is possible to take a configuration in which an axle detection signal (Sd) without voltage is output from t2 to t6.

  Another advantage of using the delay signal S3 obtained by delaying the second reception signal S2 by one period is that the noise having the same frequency as the frequency used in the axle detection system or the noise of the adjacent frequency is This noise is extracted when it enters the detection system. Next, this point will be described with reference to FIG.

  First, referring to FIGS. 3A and 3B, noises NS1 and NS2 having the same frequency and opposite phases are included in the first reception signal S1 and the second reception signal S2 during one period from t4 to t5. Is riding. If left untreated, the voltage levels of the first received signal S1 and the second received signal S2 are significantly reduced by the canceling action of the noise NS1 and NS2 having the same frequency and the opposite phase. The false detection that there exists will arise.

  As means for solving this problem, in the present invention, the arithmetic processing unit 34 of the signal processing unit 3 delays the reception signal S1 and the second reception signal S2 by one cycle (see FIG. 3C). ) To generate a subtraction signal S4 (see FIG. 3D).

That is, S1-S3 = S4
The subtraction process is performed. As shown in FIG. 3D, the subtraction signal S4 generated by this subtraction processing is a signal obtained by extracting the noise NS1 and NS2 from the time t4 to the time t5 when the noise NS1 and NS2 enters. Therefore, an axle detection device with improved noise resistance against noise having the same frequency as that of the axle detection system can be obtained. The subtraction signal S4 can be supplied from the signal processing unit 3 to, for example, a noise monitoring device and used for noise monitoring and malfunction prevention.

  Still another advantage of using the delay signal S3 obtained by delaying the second reception signal S2 by one cycle is that the noise having the same frequency as that used in the axle detection system or the noise of the adjacent frequency is Even when the vehicle enters the axle detection system, the voltage level used for axle detection can be maintained up to about twice the conventional level, and noise resistance can be improved. Next, this point will be described with reference to FIG.

  Referring to FIGS. 4A and 4B, noises NS1 and NS2 having the same frequency and opposite phases are riding on the first reception signal S1 and the second reception signal S2 during one period from t4 to t5. ing. If left untreated, the voltage levels of the first received signal S1 and the second received signal S2 are significantly reduced by the canceling action of the noise NS1 and NS2 having the same frequency and the opposite phase. The false detection that there exists will arise. This point is as described with reference to FIG.

As a means for solving this problem, the arithmetic processing unit 34 constituting the signal processing unit 3 detects the axle 5 by using the signal S6 generated by the subtraction process of the addition signal S5 and the subtraction signal S4. That is, the arithmetic processing unit 34
S1 + S3 = S5 and S5-S4 = S6
The arithmetic processing is performed. Although the noise NS1 and NS2 are present by the signal processing described above, the influence of the noise NS1 and NS2 is canceled, and the voltage level of the signal S6 is detected by the conventional axle detection as shown in FIG. 4 (e). Rises to a voltage level V2 that is about twice the voltage level V1 used in the above. Therefore, noise resistance can be improved.

  Further, the axle detection device according to the present invention has an advantage that the signal processing can be performed while keeping a simple AC transmission system, instead of taking a special code transmission system. However, if digital processing is performed, it is necessary to convert analog signals generated in the first and second receiving coils 21 and 22 into digital signals.

  FIG. 5 is a waveform diagram showing a detection operation when the axle 5 is detected using the signal S6. As described with reference to FIG. 4, even if noise enters, the signal S6 has already canceled the noise. Therefore, as shown in FIG. 5C, the signal S6 has a voltage level of the first reception signal S1 and the delay signal S3 from t0 to t2 when the axle 5 is not present and after t6. The voltage level V2 is approximately twice the voltage level V1.

From time t3 to time t5 when the axle 5 is positioned on the axle detector (1, 2), the addition signal S5 decreases by a voltage value V2 from a voltage level V2 that is twice the conventional level to almost zero voltage. Therefore, in the signal processing unit 3, by detecting the axle 5 using the signal S6, the voltage level of the signal used for axle detection can be increased to about twice the conventional level, and noise resistance can be improved. .
As shown in FIG. 5 (d), the arithmetic processing unit 34 of the signal processing unit 3 detects the axle detection signal (without voltage) (from t3 to t5 when the signal S6 decreases by the voltage value V2, for example. Sd) is output.

  While the present invention has been described with reference to the embodiment, it is needless to say that the present invention is not limited to this embodiment, and various modifications and changes can be made within the scope of the claims.

It is a figure showing roughly the composition of the axle detection device incorporating the axle detector concerning the present invention. It is a wave form diagram which shows the axle shaft detection operation | movement of the axle shaft detection apparatus shown in FIG. It is a wave form diagram which shows the noise extraction operation | movement of the axle shaft detection apparatus shown in FIG. It is a wave form diagram which shows the noise cancellation operation | movement of the axle shaft detection apparatus shown in FIG. It is a wave form diagram which shows another axle shaft detection operation | movement of the axle shaft detection apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmitter 11 Transmitting coil 2 Receiver 21 1st receiving coil 22 2nd receiving coil 3 Signal processing part 31 1st receiving part 32 2nd receiving part 33 Delay part 34 Calculation part

Claims (6)

An axle detector including one transmission coil, a first reception coil, and a second reception coil,
The first receiving coil and the second receiving coil are arranged in the vertical direction with the coil axes aligned, and individually generate signals that respond to changes in the alternating magnetic field transmitted from the transmitting coil; and , Output individually,
Axle detector. A device that includes an axle detector and a signal processing unit, and detects an axle of a train traveling on a rail,
The axle detector includes a transmission coil, a first reception coil, and a second reception coil,
The first receiving coil and the second receiving coil are arranged in the vertical direction with the coil axes aligned, and individually generate signals that respond to changes in the alternating magnetic field transmitted from the transmitting coil; and , Which is the output
The signal processing unit detects the axle based on a first reception signal S1 and a second reception signal S2 corresponding to the signals individually supplied from the first and second reception coils.
Axle detection device.   3. The axle detection device according to claim 2, wherein the first reception signal S1 and the second reception signal S2 have the same frequency and the same phase.   The axle detection device according to claim 2 or 3, wherein the signal processing unit adds the first received signal S1 and a delayed signal S3 obtained by delaying the second received signal S2 by one period. An axle detection device that detects the axle using the addition signal S5 generated by the above.   The axle detection device according to any one of claims 2 to 4, wherein the subtraction signal S4 generated by a subtraction process between the first reception signal S1 and a delay signal S3 obtained by delaying the second reception signal S2. Axle detection device that extracts noise using   6. The axle detection device according to claim 5, wherein the signal processing unit detects the axle using a signal S6 generated by a subtraction process between the addition signal S5 and the subtraction signal S4. Detection device.

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