JP2006079404A - Multiplexed transmitter / receiver for sensor signals - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor signal multiplexing transmission/reception device capable of transmitting/receiving signals from a plurality of sensors by a single signal line independently of the number of the sensors. <P>SOLUTION: This multiplexing transmission/reception device has a multiplexing transmission circuit 20 multiplexing a total n train of pulse train signals from the plurality of digital sensors into one train of pulse train signal and transmitting it; and a reception distribution circuit 30 receiving the pulse train signal from the multiplexing transmission circuit 20, and distributing it into the original n train of pulse train signals. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multiplexing transmission / reception technique for multiplexing and transmitting and receiving signals from a plurality of sensors that detect wheel rotation speed of a railway vehicle, temperature of an axle unit, and the like.

  For example, it is necessary to detect the wheel rotation speed in order to obtain the running speed of the railway vehicle or to perform sliding control for preventing the wheels of the railway car from being unevenly worn. Furthermore, in order to prevent the rolling bearing unit portion supporting the wheels from burning, it is necessary to detect the temperature of the rolling bearing unit. For this reason, a rotation support device with a sensor incorporating a rotation sensor and a temperature sensor in the rolling bearing unit supports the wheel rotatably with respect to the bearing housing, and detects the rotation speed of the wheel and the temperature of the rolling bearing unit. Has been done.

  As this type of rotation support device with a sensor, there is provided a magnetic sensor capable of detecting an alternating magnetic characteristic change due to rotation by fixing an encoder having a gear-like outer periphery to an outer end of an axle or an inner ring side surface of a bearing supporting the axle. 2. Description of the Related Art There is known a device that is arranged to be opposed to the outer periphery of an encoder to serve as a rotation sensor and includes a sensor unit including a temperature sensor and a vibration sensor and is fixed to a housing. The rotational speed sensor also has a purpose of generating two pulse train signals having a phase difference of 90 degrees from each other in order to determine the rotational direction. The temperature sensor compares an analog signal generated when the bearing temperature changes with a dangerous temperature set in advance in the sensor unit. If the dangerous temperature is exceeded, a “1” signal is output. In some cases, a digital signal is generated such as generating a 0 "signal (see Patent Document 1).

  Furthermore, a plurality of sensor-equipped bearing devices having temperature sensors are provided, signals from the plurality of sensor-equipped bearing devices are taken into a computer, and an abnormal sensor-equipped bearing device based on the maximum value, average value, standard deviation, etc. of the sensor signal There is also known a structure configured to discriminate (see Patent Document 2).

  The monitoring of such bearings is not limited to rail vehicles. For example, monitoring of bearings is important also in automobiles and mechanical facilities, and many sensors are used for that purpose. In order to transmit a sensor signal, signal lines corresponding to the number of sensors are required. Therefore, as the number of sensors increases, the cable for transmitting sensor signals becomes multi-core and thick, the cable weight increases, and the wiring work for firmly fixing the cable also becomes large.

  Thus, as a technique for reducing the number of signal lines for transmitting sensor signals, a detection device has been proposed that uses a switching circuit and a resistance circuit to limit the number of signals to be transmitted to a small number (see Patent Document 3). ).

Furthermore, the analog signals from the temperature sensor and vibration sensor are added and transmitted, and the received signal is passed through the low-pass filter and high-pass filter, so that the temperature detection signal is extracted by the low-pass filter and the vibration detection signal is extracted by the high-pass filter. A transmission method was proposed (see Patent Document 4).
Japanese Patent Laid-Open No. 2003-13948 JP 2003-262220 A JP 2002-288776 A JP 2004-94393 A

  As described above, in a system for transmitting signals from a plurality of sensors, signal lines are required as many as the number of sensors. Therefore, as the number of sensors increases, the cable for transmitting sensor signals is multi-core and thick. As a result, there is a problem that the weight of the cable increases. With respect to such problems, the techniques described in Patent Documents 3 and 4 limit the number of signals to be transmitted, or multiplex-transmit signals from a specific number of sensors using the frequency difference between the signals. However, when the number of sensors increases or decreases, there is a problem that a significant change in circuit design or signal processing is required.

  The present invention has been made in view of the above-described circumstances, and an object thereof is sensor signal multiplexing transmission / reception capable of transmitting / receiving signals from a plurality of sensors through a single signal line regardless of the number of sensors. To provide an apparatus.

In order to achieve the above-described object, a sensor signal multiplexing transmission / reception apparatus according to the present invention is characterized by the following (1), (2), (3), (4) and (5).
(1) a multiplexed transmission circuit that multiplexes and transmits a total of n pulse train signals from a plurality of digital sensors into one pulse train signal;
A reception distribution circuit that receives the pulse train signal from the multiplexed transmission circuit and distributes it to the original n-sequence pulse train signal;
Having provided.
(2) a modulation circuit that converts analog signals from a plurality of analog sensors into pulse train signals;
A multiplexed transmission circuit that multiplexes and transmits a total of n pulse train signals from the modulation circuit into a single pulse train signal;
A reception distribution circuit that receives the pulse train signal from the multiplexed transmission circuit and distributes it to the original n-sequence pulse train signal;
A demodulation circuit that demodulates and outputs an n-sequence pulse train signal from the reception distribution circuit to an original analog signal;
Having provided.
(3) a modulation circuit that converts an analog signal from an analog sensor into a pulse train signal;
A multiplexed transmission circuit that multiplexes and transmits a total of n pulse train signals composed of a pulse train signal from the modulation circuit and a pulse train signal from at least one digital sensor into one pulse train signal;
A reception distribution circuit that receives the pulse train signal from the multiplexed transmission circuit and distributes it to the original n-sequence pulse train signal;
A demodulating circuit for demodulating and outputting a signal corresponding to the analog sensor out of n pulse train signals from the reception distribution circuit to an original analog signal and outputting a signal corresponding to the digital sensor as it is;
Having provided.
(4) In the sensor signal multiplexing transmission / reception device according to any one of the above (1) to (3), the digital sensor includes wheel rotation speed, wheel rotation direction, bearing vibration, and bearing temperature. It is a sensor for detecting at least one of them.
(5) In the sensor signal multiplexing transmission / reception device having any one of the configurations (1) to (3), the analog sensor is a sensor for detecting at least one of a bearing temperature and a bearing vibration. .

According to the sensor signal multiplexing transmission / reception apparatus having the above configuration (1), a total of n pulse train signals from a plurality of digital sensors are multiplexed into one pulse train signal and transmitted. Since the signals are distributed to the pulse train signals in a row, signals from a plurality of sensors can be transmitted and received through one signal line regardless of the number of digital sensors.
According to the sensor signal multiplexing transmission / reception apparatus having the above configuration (2), analog signals from a plurality of analog sensors are converted into pulse train signals, respectively, to obtain a total of n pulse train signals, which are then converted into one pulse train signal. Is multiplexed and transmitted to the original n-sequence pulse train signal on the receiving side, and demodulated and output to the original analog signal. Therefore, a plurality of signals can be transmitted by one signal line regardless of the number of analog sensors. It is possible to send and receive signals from the sensors.
According to the sensor signal multiplexing transmission / reception device having the configuration (3), the analog signal from the analog sensor is converted into a pulse train signal, and the total number of the converted pulse train signal and the pulse train signal from at least one digital sensor. An n-sequence pulse train signal is multiplexed and transmitted to a single train pulse train signal, and is distributed to the original n-sequence pulse train signal on the receiving side, and a signal corresponding to an analog sensor among the distributed n-sequence pulse train signals. Is demodulated and output to the original analog signal, and the signal corresponding to the digital sensor is output as it is, so that signals from a plurality of sensors can be transmitted and received by one signal line regardless of the number of digital sensors and analog sensors. be able to. Therefore, according to this sensor signal multiplexing transmission / reception apparatus, at least one digital sensor and at least one analog sensor can be mixedly used.
According to the sensor signal multiplexing transmission / reception apparatus having the configuration (4), the digital sensor detects at least one of the rotational speed of the wheel, the rotational direction of the wheel, the vibration of the bearing, and the temperature of the bearing. be able to.
According to the sensor signal multiplexing transmission / reception device having the configuration (5), the analog sensor can detect at least one of the temperature of the bearing and the vibration of the bearing.

  According to the present invention, signals from a plurality of sensors can be transmitted and received through one signal line regardless of the number of sensors.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[First embodiment]
FIG. 1 is a circuit diagram showing an example of a sensor signal multiplexing transmission / reception apparatus according to the present invention. FIG. 2 is a sectional view showing the structure of a hub bearing unit with a load sensor.

  As shown in FIG. 2, a hub bearing unit with a load sensor (hereinafter simply referred to as a bearing unit) 1 includes one inner ring rotational speed detection sensor (hereinafter referred to as a rotation sensor) 2 and a pair of cages. Revolution speed detection sensors (hereinafter referred to as revolution sensors) 3a and 3b are incorporated. Hall sensors are used for these sensors. The rotation sensor 2 is provided to face the outer peripheral surface of the ABS encoder 4 whose outer peripheral portion is formed in a gear shape. The revolution sensors 3a and 3b are provided to face the inward surfaces of a pair of cage revolution speed detection encoders (multipolar magnets) 5a and 5b formed in a ring shape. Each of these sensors generates a pulse train signal that changes between a high voltage and a low voltage as the encoders rotate relative to each other.

  As shown in FIG. 1, the sensor signal multiplexing transmission / reception apparatus 10 includes a multiplexing transmission circuit 20 and a reception distribution circuit 30. In the multiplexed transmission circuit 20, a 4-to-1 selection circuit 21 having one output terminal (Out) for four input terminals (In0, In1, In2, In3) and a quaternary counter 22 are provided. ing. In the reception distribution circuit 30, a one-to-four distribution circuit 31 having four output terminals (Out0, Out1, Out2, Out3) for one input terminal (In) and a quaternary counter 32 are provided. Yes. The output terminal (Out) of the selection circuit 21 and the input terminal (In) of the distribution circuit 31 are connected to each other by one signal line 41 in the cable 40. A power line 42 is provided in the cable 40 together with the signal line 41.

  The pulse train signal (sig0) from the rotation sensor 2 is input to the first input terminal (In0) of the selection circuit 21. Pulse train signals (sig1, sig2) from the revolution sensors 3a, 3b are input to the second and third input terminals (In1, In2) of the selection circuit 21, respectively. The selection circuit 21 is provided with a selection signal input terminal (Sel) so that two selection signals (Q1, Q2) output from the quaternary counter 22 are input.

  The selection circuit 21 performs a logical product (AND) operation of two selection signals (Q1, Q2) therein, and a synchronization signal (sync) generated as a result thereof is supplied to its fourth input terminal (In3). input. Then, the selection circuit 21 outputs a pulse train signal (multiplexed signal) obtained by multiplexing the pulse train signals (sig0, sig1, sig2) and the synchronization signal (sync) from the three sensors 2, 3a, 3b into one row. .

  The multiplexed signal output from the selection circuit 21 is input to the distribution circuit 31 in the reception distribution circuit 30 through the signal line 41 in the cable 40. In addition, the reception distribution circuit 30 is provided with a distribution signal input terminal (Div), to which two distribution signals (Q1, Q2) output from the quaternary counter 32 are input.

  When the selection circuit 21 and the distribution circuit 31 are synchronized with each other, the first to third output terminals (Out0, Out1, Out2) of the distribution circuit 31 are pulse train signals from the three sensors 2, 3a, 3b, respectively. (Sig0, sig1, sig2) is temporally selected according to the value of the distribution signal (Q1, Q2), held, and output. At this time, the distribution circuit 31 performs an AND operation on the two distribution signals (Q1, Q2) therein, and sends a synchronization signal (sync *) generated as a result from its fourth output terminal (Out3). Output. The synchronization signal (sync *) is used to establish synchronization on the reception distribution circuit 30 side.

  The quaternary counter 32 in the reception distribution circuit 30 performs an AND operation result of a negative phase clock signal (nclock) which is a negative (NOT) of the distribution signal (Q1, Q2) and the clock signal (clock) and a synchronization signal (sync *). Is driven by a logical sum (OR) output of a delayed pulse (τ) generated by a negative logical sum (NOR) and a negative phase clock signal (nclock).

  The power from the power supply (+ V, 0) is supplied from the reception distribution circuit 30 side to the multiplexed transmission circuit 20 side through the power line 42 in the cable 40, and is supplied to each sensor 2, 3a, 3b via the multiplexed transmission circuit 20. Is done. The clock signal (clock) for controlling the operation timing of both circuits 20 and 30 is superimposed on the + V power line by a capacitor coupling from a driver (not shown), but the clock signal (clock) is also input to the input side of the power line. A coil is inserted to prevent A coil is also inserted into the power supply line on the multiplexed transmission circuit 20 side, and the clock signal (clock) is taken out at the preceding stage to prevent leakage of the clock signal (clock) to the power line on the sensor side. .

  Next, the operation of the sensor signal multiplexing transmitter / receiver 10 will be described in detail with reference to the timing chart of FIG.

  When the quaternary counter 22 is driven at the rising edge of the clock signal (clock), the selection circuit 21 outputs a synchronization signal (sync) that is the result of the AND operation of the selection signals (Q1, Q2). The fourth input terminal In3. The pulse train signal (sig0) from the rotation sensor 2 is input to the first input terminal In1 of the selection circuit 21. Pulse train signals (sig1, sig2) from the revolution sensors 3a, 3b are input to the second and third input terminals In1, In2 of the selection circuit 21, respectively. The selection signal (Q1, Q2) input from the quaternary counter 22 to the selection circuit 21 corresponds to each combination of (0, 0), (1, 0), (0, 1) and (1, 1). During this period, the input pulse train signals (sig0, sig1, sig2) and the synchronization signal (sync) are selected, and a multiplexed signal is formed and output. Of the multiplexed signal, the time corresponding to the synchronization signal (sync) is always one bit. Therefore, although “1” may always be input to the fourth input terminal In3 of the selection circuit 21, by separately generating a synchronization signal (sync), the counter on the multiplexed transmission circuit 20 side will be described later. It is possible to detect malfunctions and malfunctions.

  When the reception distribution circuit 30 receives the multiplexed signal and the synchronization is established, the combination (0, 0), (1, 0) of the distribution signal (Q1, Q2) output from the quaternary counter 32 is established. ), (0, 1) and (1, 1), the distribution circuit 31 distributes the multiplexed signals by dividing them in time, and writes them in a latch register (not shown) to hold them. The quaternary counter 32 and the latch register are driven by a reverse phase clock signal (nclock). From the output terminals of the latch registers, the input pulse train signals (sig0, sig1, sig2) on the multiplexed transmission circuit 20 side are reproduced and output. When synchronization is established, the synchronization signal (sync *) is always “1”.

  In the present invention, the signal at the input terminal (In0, In1, In2) of the selection circuit 21 on the multiplexed transmission circuit 20 side and the signal at the output terminal (Out0, Out1, Out2) of the distribution circuit 31 on the reception distribution circuit 30 side Must be exactly the same. For this purpose, synchronization must be established so that each input terminal (In0, In1, In2) of the selection circuit 21 and each corresponding output terminal (Out0, Out1, Out2) of the distribution circuit 31 are selected simultaneously. . When synchronization is not established (see FIG. 4), since a signal corresponding to any sensor signal appears at the output terminal of the synchronization signal (sync *), the synchronization signal (sync *) is set to “0”. Can be. When the synchronization signal (sync *) is “0”, a delayed pulse is generated based on the negative phase clock signal (nclock) when the AND operation value of the distribution signal (Q1, Q2) is “1”. Since it is added to the opposite phase clock signal (nclock), the counter value advances by the number of added pulses. When a synchronization signal (sync *) of “0” continues, synchronization is established within a maximum of 3 pulses. When the synchronization signal (sync *) becomes “1”, a delayed pulse is not generated. FIG. 4 shows a state in which synchronization is established when the synchronization shift is the clock period T (1 / frequency), 2T, and 3T. Further, when a normal synchronization signal (sync) is not generated due to some abnormality in the quaternary counter 22 or the selection circuit 21 on the multiplexed transmission circuit 20 side, the synchronization signal (sync *) on the reception distribution circuit 30 side is used. Since synchronization cannot be established, the delayed pulse continues to be generated, and an abnormality can be easily detected.

  As described above, according to the sensor signal multiplexing transmitter / receiver 10, the total of three pulse train signals (sig0, sig1, sig2) from the three sensors 2, 3a, 3b are multiplexed into one pulse train signal. Since it is transmitted and distributed to the original three pulse train signals on the receiving side, signals from the three sensors 2, 3 a, 3 b can be transmitted and received by one signal line 41.

In addition, instead of the quaternary counters 22 and 32, counters of n + 1 or higher are used, the selection circuit 21 is a circuit of n + 1 or higher, and the distribution circuit 31 is a circuit of 1 to n + 1 or higher, corresponding to sync and sync *. By making this, it is possible to flexibly cope with an increase or decrease in the number of sensors n.
In the case of the above example, a sensor signal multiplexing transmission / reception device configured for n sensors can be used for fewer than n sensors. In this case, the remaining input terminals of the selection circuit 21 should be set to “0”. This is because if it is set to “1”, the output of the selection circuit 21 cannot be distinguished from the synchronization signal (sync), and an error occurs in synchronization. This is not the case with other synchronization methods.

  The method of synchronizing the multiplexed transmission circuit 20 side and the reception distribution circuit 30 side is not limited to the method described above. For example, only one of the multiplexed transmission circuit 20 side and the reception distribution circuit 30 side uses a counter to generate a synchronization signal once in four cycles of a clock signal (clock) and send it to the other to establish synchronization. It is also possible. In addition, since the functions of the selection circuit 21 and the distribution circuit 31 can be said to be serial / parallel conversion and parallel / serial conversion of signals, a well-known shift register can be used instead. Furthermore, in the above example, the clock signal (clock) is transmitted by superimposing it on the power line 42 with the intention of minimizing the number of wires in the cable 40, and is branched and extracted on the receiving side. (Clock) may be sent from the generation side to the reception side using a dedicated signal line. The frequency of the clock signal (clock) is determined according to the allowable error (or time resolution) of the pulse detection time from the sensor. In other words, if the time resolution is 10 μsec, 200 kHz or more that can be sampled at 5 μsec, which is half of that, is appropriate.

[Second Embodiment]
FIG. 5 is a circuit diagram showing a second embodiment of the sensor signal multiplexing transmission / reception apparatus according to the present invention.

  In addition to the device 10 of FIG. 1, the sensor signal multiplexing transmission / reception device 50 converts each analog signal from a plurality of analog sensors into a pulse train signal and inputs it to the selection circuit 21 of the multiplexing transmission circuit 20. And a demodulation circuit 70 that demodulates and outputs the m-sequence pulse train signal from the distribution circuit 31 of the reception distribution circuit 30 to the original analog signal. However, in the device 10 of FIG. 1, instead of the quaternary counters 22 and 32, an m + 1-ary counter is used, the selection circuit 21 is an m + 1 to 1 circuit, and the distribution circuit 31 is a 1 to m + 1 circuit. Create sync and sync *.

  Here, it is assumed that the analog sensor is a temperature sensor that monitors the temperature of a plurality of bearings of the railway vehicle, and analog signals (sensor signals) from m temperature sensors input to the modulation circuit 60 are T1,. Let Tm-1 and Tm.

  In the modulation circuit 60, m PWM circuits (that is, pulse width modulation circuits) 61 (1) to 61 (m) and PWM circuits 61 (1) to 61 (m) to which each analog signal is individually input. And a triangular wave generator 62 for supplying a triangular wave. Each of the PWM circuits 61 (1) to 61 (m) converts the analog signals T1,..., Tm-1, and Tm input to the pulse circuits into modulated pulse widths according to the magnitude relationship with the triangular wave. That is, as shown in FIG. 6, the inputted analog signal is converted into a PWM signal that becomes a high voltage while the voltage of the analog signal is larger than that of the triangular wave and becomes a low voltage when the voltage is small. By this modulation circuit 60, all analog signals from the m temperature sensors are subjected to pulse width modulation, and input to the corresponding input terminals In (0) to In (m-1) of the selection circuit 21 as parallel pulse train signals. Is done.

  The selection circuit 21 multiplexes the total number m of pulse train signals from the modulation circuit 60 into one pulse train signal and transmits it to the distribution circuit 31 through one signal line 41 in the cable 40. The distribution circuit 31 receives the pulse train signal from the selection circuit 21 and regenerates it to the original m-sequence PWM signal.

  The m columns of PWM signals distributed by the distribution circuit 31 are input to the demodulation circuit 70.

  In the demodulating circuit 70, m low-pass filters 71 (1) to 71 (m) to which each PWM signal from the distribution circuit 31 is individually input are provided. Each of the low-pass filters 71 (1) to 71 (m) is equivalent to the output signals (analog signals) T1,..., Tm-1, Tm of the original temperature sensors by averaging the input PWM signals. Output analog signals. By this demodulation circuit 70, all PWM signals from the distribution circuit 31 are demodulated into analog signals equivalent to the original analog signals T1, ..., Tm-1, Tm.

  According to the sensor signal multiplexing transmitter / receiver 50 configured as described above, analog signals from m temperature sensors are each subjected to pulse width modulation to obtain a total of m columns of PWM signals, which are then converted into one column of pulse sequences. The signal is multiplexed and transmitted, and it is regenerated to the original m-sequence PWM signal on the receiving side, demodulated into an analog signal equivalent to the output signal of the original temperature sensor, and output, so it is related to the number of temperature sensors In addition, signals from a plurality of temperature sensors can be transmitted and received with one signal line.

  Note that the triangular wave generator 62 may be placed in the demodulation circuit 70 and the generated triangular wave may be transmitted to the PWM circuits 61 (1) to 61 (m) in the modulation circuit 60. In any case, the period of the triangular wave (T) can be determined so as to satisfy, for example, T ≧ ΔT ÷ ε × 100 from the time resolution (ΔT) and the required accuracy (ε%) of the analog signal. . Therefore, if ΔT = 1 μsec and ε = 0.1, it should be T ≧ 1 msec, that is, a triangular wave with a frequency of 1 KHz or less.

[Third embodiment]
As a third embodiment of the present invention, a sensor signal multiplexing transmission / reception device capable of intermixing a plurality of digital sensors and a plurality of analog sensors will be described. For example, for the maintenance of railway vehicle bearings, vibration is an important monitoring item as well as bearing temperature. For safe control, the rotation direction (forward rotation, reverse rotation) may be monitored simultaneously with the rotation speed of the wheel. For this purpose, a sensor that generates two-phase (A-phase, B-phase) signals that differ depending on the rotation direction of the wheel is installed in the bearing unit. In this type of sensor, for example, a gear made of a magnetic material is attached to an inner ring or shaft of a bearing, and two Hall sensors are arranged opposite to the outer periphery of the gear so that the A phase and B are rotated as the gear rotates. It is configured to generate a two-phase pulse train of phases. As shown in FIG. 8, the forward rotation or the reverse rotation can be determined from the positional relationship between the A phase and the B phase, and at the same time, the rotation speed can be evaluated based on the pulse generation rate. An acceleration sensor is used for monitoring the vibration. Since the acceleration sensor is sensitive to shocking vibrations in the high frequency range, it is effective in detecting serious damage such as separation of the inner ring and outer ring of the bearing. The vibration signal output from the acceleration sensor is input to the peak hold circuit. The peak hold circuit is configured to detect the peak of the input vibration signal and slowly attenuate it while maintaining it for a while. Following a slight attenuation, a new peak hold is made. As a result, the peak hold signal due to a long-period impact or sudden impact is greatly attenuated, so that it can be distinguished from bearing damage.

  FIG. 7 is a circuit diagram showing a third embodiment of the sensor signal multiplexing transmission / reception apparatus according to the present invention. In the modulation circuit 60 of the sensor signal multiplexing transmission / reception apparatus 80, two PWM circuits 61 (1) and 61 (2) and a triangular wave generation for supplying a triangular wave to both PWM circuits 61 (1) and 61 (2) are generated. And a peak hold circuit 63 connected to the input terminal of one PWM circuit 61 (1).

  A vibration signal α from the acceleration sensor is input to the peak hold circuit 63. Then, a peak hold signal (analog signal) from the peak hold circuit 63 is input to one PWM circuit 61 (1). The output signal (analog signal) T of the temperature sensor is input to the other PWM circuit 61 (2). Each PWM circuit 61 (1), 61 (2) converts the analog signal input to each into a pulse width modulated wave according to the magnitude relationship with the triangular wave (see FIG. 6). By this modulation circuit 60, all analog signals from the acceleration sensor and the temperature sensor are subjected to pulse width modulation, and input to the corresponding input terminals In (2) and In (3) of the selection circuit 21 as parallel pulse train signals. . Further, the two-phase signals of the A phase and the B phase from the two hall sensors (rotation sensors) are input to the corresponding input terminals In (0) and In (1) of the selection circuit 21.

  The selection circuit 21 multiplexes a total of four pulse train signals from the modulation circuit 60 into one pulse train signal, and transmits it to the distribution circuit 31 in the reception distribution circuit 30 through one signal line 41 in the cable 40. To do. The distribution circuit 31 receives the pulse train signal from the selection circuit 21 and distributes it to the original four pulse train signals.

  The four pulse train signals distributed by the distribution circuit 31 are input to the demodulation circuit 70.

  In the demodulating circuit 70, two low-pass filters 71 (1) and 71 (2) are provided to which respective PWM signals corresponding to the four pulse train signals from the distribution circuit 31 are individually input. . Each of the low-pass filters 71 (1) and 71 (2) averages the input PWM signals, and reproduces the peak hold signal of the vibration signal of the acceleration sensor and the analog signal of the temperature sensor, respectively. The A-phase and B-phase two-phase signals A and B from the distribution circuit 31 are sent to a rotation discriminating circuit (not shown) through the demodulation circuit 70 and used for evaluating the rotation direction and rotation speed of the wheels.

  As described above, according to the third embodiment, the analog signal from the analog sensor is converted to a pulse train signal by performing pulse width modulation, multiplexed and transmitted / received in the same manner as the pulse train signal from the digital sensor, and the receiving side. After the multiplexed signal is distributed to the parallel pulse train signal, the pulse train signal corresponding to the analog sensor can be demodulated (PWM demodulated) to reproduce the original analog signal, so the analog sensor and digital sensor can be mixed. is there.

  In addition, any of the above-described sensor signal multiplexing transmission / reception apparatuses can multiplex a plurality of sensor signals and transmit / receive them with a single signal line, greatly contributing to the weight reduction of the cable and the reduction of wiring work.

It is a circuit diagram which shows the 1st example of a form of this invention. It is sectional drawing which shows the structure of a hub bearing unit with a load sensor. It is a timing diagram which shows the operation example of the sensor signal multiplexing transmission / reception apparatus shown in FIG. FIG. 3 is a timing diagram illustrating an operation example when a synchronization shift occurs in the sensor signal multiplexing transmission / reception apparatus illustrated in FIG. It is a circuit diagram which shows the 2nd example of a form of this invention. It is a principle explanatory view of pulse width modulation. It is a circuit diagram which shows the 3rd form example of this invention. It is a waveform diagram of a two-phase pulse train of A phase and B phase during forward rotation and reverse rotation.

Explanation of symbols

1: Bearing unit 2: Rotation sensor 3a, 3b: Revolution sensor 10: Sensor signal multiplexing transmission / reception device 20: Multiplex transmission circuit 21: Selection circuit 30: Reception distribution circuit 31: Distribution circuit 40: Cable 41: Signal line 50: Sensor signal multiplexing transmission / reception device 60: modulation circuit 61 (1) to 61 (m): PWM circuit 63: peak hold circuit 70: demodulation circuit 71 (1) to 71 (m): low-pass filter 80: transmission / reception of sensor signal multiplexing Devices sig0, sig1, sig2: pulse train signals T1, ..., Tm-1, Tm: analog signals

Claims (5)

A multiplexed transmission circuit that multiplexes and transmits a total of n pulse train signals from a plurality of digital sensors into one pulse train signal;
A reception distribution circuit that receives the pulse train signal from the multiplexed transmission circuit and distributes it to the original n-sequence pulse train signal;
A sensor signal multiplexing transmission / reception apparatus comprising: A modulation circuit that converts analog signals from a plurality of analog sensors into pulse train signals, and
A multiplexed transmission circuit that multiplexes and transmits a total of n pulse train signals from the modulation circuit into a single pulse train signal;
A reception distribution circuit that receives the pulse train signal from the multiplexed transmission circuit and distributes it to the original n-sequence pulse train signal;
A demodulation circuit that demodulates and outputs an n-sequence pulse train signal from the reception distribution circuit to an original analog signal;
A sensor signal multiplexing transmission / reception apparatus comprising: A modulation circuit that converts an analog signal from an analog sensor into a pulse train signal;
A multiplexing transmission circuit for multiplexing and transmitting a total of n pulse train signals consisting of a pulse train signal from the modulation circuit and a pulse train signal from at least one digital sensor into one pulse train signal;
A reception distribution circuit that receives the pulse train signal from the multiplexed transmission circuit and distributes it to the original n-sequence pulse train signal;
A demodulating circuit for demodulating and outputting a signal corresponding to the analog sensor out of n-sequence pulse train signals from the reception distribution circuit and outputting the signal corresponding to the digital sensor as it is;
A sensor signal multiplexing transmission / reception apparatus comprising:   4. The digital sensor according to claim 1, wherein the digital sensor is a sensor for detecting at least one of a rotation speed of a wheel, a rotation direction of the wheel, a vibration of the bearing, and a temperature of the bearing. The sensor signal multiplexing transmission / reception apparatus according to claim 1.   4. The sensor signal multiplexing transmission / reception apparatus according to claim 1, wherein the analog sensor is a sensor for detecting at least one of a bearing temperature and a bearing vibration.

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