JP2006189321A - Rotational speed detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotational speed detection device capable of maintaining the reliability of detected rotational speed, by easily detecting the disconnections in wirings that connect the sensor part and the receiving part. <P>SOLUTION: The rotational speed detection device is constituted, such that the resistance R1 is connected between the collector and the emitter of an open collector transistor in the sensor part 10, and the input part of the photocoupler 301 is serially connected to the power source line 22 in the receiver part 31. At normal state of the receiver part 31, the voltage of the rotational speed signal is equal to the voltage of ground voltage (0 V), or the source voltage Vs divided by the resistance R1 to R2. If disconnection has occurred in the signal line 21 or the ground line 23 of the wiring, the voltage of the output terminal of the receiver part 31 always becomes equal to the source voltage Vs, thereby the disconnection can definitely be discriminated. Furthermore, when the source line 22 or the grounding line 23 is disconnected the output transistor of the photocoupler 301 turns off, the voltage equal to the source voltage Vs is outputted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotational speed detection device, and more particularly to a rotational speed detection device that detects the rotational speed of a bearing device or the like used in a railway vehicle, an automobile, a machine facility, or the like.

  In bearing devices and the like in railway vehicles, automobiles, mechanical equipment, and the like, various controls are performed based on the detected rotational speed. FIG. 5 shows a conventional structure in which the rotational speed of the rolling bearing is detected by a rotational speed sensor installed in the vicinity of the vehicle bearing. The axle 64 is rotatably supported by a shaft box 62a of the bearing device via a rolling bearing 63. A sensor unit 60 including a rotational speed detection sensor is attached to the lid 62b attached to the axle box 62a so as to face the encoder 66 fitted to the end cap 65 of the axle 64. The rotational speed of the axle 64 is detected via the encoder 66 (see, for example, Patent Document 1).

  FIG. 6 is a block diagram showing an example of a schematic configuration when the rotational speed signal detected by the sensor unit 60 as described above is transmitted to a receiving unit installed in the vehicle main body via a cable. In the figure, the sensor unit 60 is connected to a receiving unit 80 via a wiring 70 including a signal line 71, a power supply line 72, and a ground line 73. The signal detected by the rotation speed detection sensor 61 of the sensor unit 60 is switched by an open collector transistor Q6 and output as a binary rotation speed signal, and is transmitted to the reception unit 80 via the wiring 70. A pull-up resistor R8 is connected to the output terminal of the receiving unit 80, and outputs a rotation speed signal of a ground potential (0V) or a power supply voltage (Vs, for example, 12V).

  Further, as a conventional rotational speed detection device, the rotational speed detection sensor is held in a single holder, and the detected rotational speed signal is wirelessly transmitted to a receiving unit installed in the vehicle body, thereby breaking the wire. A technique for avoiding the failure involved is known (for example, see Patent Document 2).

  Furthermore, in a bearing device provided with a temperature sensor that detects the temperature of the bearing, for example, a device that detects when the signal output from the temperature sensor is 0 V as a disconnection is known (see, for example, Patent Documents 3 to 5). .)

Special table 2001-500707 gazette JP 2003-121454 A JP 2003-75266 A JP 2003-98011 A Japanese Patent Laid-Open No. 2004-3573

  However, in the circuit configuration shown in FIG. 6, when any one of the three wires 70 is disconnected or when any wire is disconnected, the power supply voltage Vs (for example, 12 V) is applied to the output terminal of the receiving unit 80. Appears, it is indistinguishable from the normal case where the wiring is not disconnected, and therefore there is a problem that the disconnection cannot be detected.

  Moreover, in the rotational speed detection apparatus described in Patent Document 2, since the signal from the sensor is wirelessly transmitted to the reception unit, the disconnection detection of the wiring connecting the sensor unit and the reception unit is not considered.

  Furthermore, the bearing devices described in Patent Documents 3 to 5 are detections of disconnection in a sensor that outputs a continuous output signal such as a temperature sensor, and a pulse signal is output using a transistor or the like, for example, as a rotation speed detection sensor. When outputting, both the power supply voltage and 0V are output, and when not rotating, even if the output is 0V, it is not disconnected. For this reason, in the case of a rotational speed detection sensor, it is necessary to detect a disconnection by another method.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to make it possible to easily detect the disconnection of the wiring connecting the sensor unit and the receiving unit, and to improve the reliability of the detected rotation speed. An object of the present invention is to provide a rotation speed detection device that can be secured.

The above object is achieved by the following configuration.
(1) A sensor unit including a rotation speed sensor that outputs a binary rotation speed signal according to ON / OFF of a transistor having an open collector or an open drain configuration, a signal line that transmits the rotation speed signal, and a power supply voltage to the sensor unit A rotational speed having a wiring composed of a power supply line and a grounding line for supplying power, and a receiving section for receiving and outputting the rotational speed signal by connecting a receiving end connected to the signal line of the wiring with a pull-up resistor A detection device,
The sensor unit includes a resistor connected between the output terminal of the transistor and the ground,
A rotation speed detection device that detects disconnection of the signal line or the ground line based on the potential of the signal line in the receiving unit.
(2) A sensor unit including a rotation speed sensor that outputs a binary rotation speed signal in response to ON / OFF of a transistor having an open collector or open drain configuration, a signal line that transmits the rotation speed signal, and a power supply voltage to the sensor unit A rotational speed having a wiring composed of a power supply line and a grounding line for supplying power, and a receiving section for receiving and outputting the rotational speed signal by connecting a receiving end connected to the signal line of the wiring with a pull-up resistor A detection device,
The receiver includes a photocoupler having an input terminal connected in series to the power line,
A rotation speed detection device that detects disconnection of the power supply line or the ground line based on the output of the photocoupler.
(3) A sensor unit including a rotation speed sensor that outputs a binary rotation speed signal in response to ON / OFF of a transistor having an open collector or an open drain configuration, a signal line that transmits the rotation speed signal, and a power supply voltage to the sensor unit A rotational speed having a wiring composed of a power supply line and a grounding line for supplying power, and a receiving section for receiving and outputting the rotational speed signal by connecting a receiving end connected to the signal line of the wiring with a pull-up resistor A detection device,
The sensor unit includes a resistor connected between the output terminal of the transistor and the ground, and the receiving unit includes a photocoupler in which an input terminal is connected in series to the power line.
A rotational speed detection device that detects disconnection of the wiring based on a potential of the signal line and presence / absence of an output of the photocoupler in the receiver.
(4) The rotational speed detection device according to any one of (1) to (3), wherein the rotational speed detection sensor is installed in the vicinity of a vehicle bearing device.

  According to the rotational speed detection device of the present invention, the sensor unit includes a resistor connected between the output terminal of the transistor and the ground, and the reception unit includes a photocoupler in which the input terminal is connected in series to the power line. By providing at least one of the above, the presence or absence of disconnection in the wiring connecting the sensor unit and the receiving unit can be easily detected with a simple configuration, and the reliability of the detected rotation speed can be ensured.

  Embodiments of a rotational speed detection device according to the present invention will be described below with reference to the drawings.

(First embodiment)
First, a rotational speed detection device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 shows a schematic configuration of a vehicle bearing device in which the rotational speed detection device of the first embodiment is installed. In the bearing device shown in FIG. 1, the axle 42 into which the wheel 41 is fitted is rotatably disposed on the housing 43 via a rolling bearing 44.

  The sensor unit 10 is fixed to the outer surface of the housing 43 through a mounting hole communicating with the inside. The sensor unit 10 includes a rotation speed detection sensor 101 (see FIG. 2) for detecting the rotation speed of the rolling bearing 44 by an encoder 45 attached to the axle 42, and the detected rotation speed signals are many. The signal is transmitted to the receiving unit 30 via the wiring 20 accommodated in the core cable. The receiving unit 30 is included in the control device 35 installed in the vehicle body.

Next, the configuration and operation of the rotation speed detection device including the sensor unit 10, the wiring 20, and the reception unit 30 will be described with reference to FIG.
In FIG. 2, the sensor unit 10 detects the rotation of the encoder 45 magnetically or optically to generate a rotation speed signal corresponding to the rotation speed, amplifies the detected rotation speed signal, and outputs a binary pulse signal. Rotational speed detection sensor 101 including a transistor Q1 having a grounded emitter and an open collector configuration, and a resistor R1 connected between the collector and emitter of transistor Q1. The wiring 20 includes a signal line 21 that transmits a rotation speed signal output from the transistor Q1 through an open collector to the receiving unit 30, a power supply line 22 that supplies the power supply voltage Vs from the receiving unit 30 to the sensor unit 10, and a sensor. The unit 10 and the receiving unit 30 include a ground line 23 for holding a ground potential. The receiving unit 30 includes a pull-up resistor R <b> 2 connected between the power supply voltage Vs and the signal line 21 and outputs a rotation speed signal transmitted from the sensor unit 10 to the control device 35.

  Next, the operation of this rotational speed detection device will be described. The transistor Q1 is turned on / off according to a rotation speed signal input to the base from the rotation speed detection sensor 101. First, when the transistor Q1 is turned on, a current flows from the power supply voltage Vs of the receiving unit 30 through the pull-up resistor R2, the signal line 21, the collector and the emitter of the transistor Q1, and the collector becomes almost the ground voltage (0 V).

  On the other hand, when the transistor Q1 is off, a current flows through the pull-up resistor R2, the signal line 21, and the resistor R1, and the collector is a voltage obtained by dividing the power supply voltage Vs by the resistors R1 and R2, Vs · R1 / (R1 + R2). Become.

  In this way, the sensor unit 10 outputs a binary signal having a voltage corresponding to the ground voltage (0 V) or Vs · R1 / (R1 + R2) corresponding to the detected rotation speed. This binary signal is transmitted to the receiving unit 30 via the signal line 21 and is output from the output terminal to the control device 35.

  Here, consider a case where the signal line 21 is disconnected. The rotation speed signal detected by the sensor unit 10 cannot be transmitted regardless of whether the transistor Q1 is on or off, and no current flows through the pull-up resistor R2 of the receiving unit 30 connected in series to the signal line 21. Therefore, the potential of the output terminal of the receiving unit 30 is always equal to the power supply voltage Vs, and can be clearly distinguished from the voltage at the normal time.

  When the ground line 23 is disconnected, no current flows through the signal line 21 and the signal line 21 is disconnected, and the potential of the output terminal is always equal to the power supply voltage Vs. Can be clearly distinguished.

  Therefore, in the rotational speed detection device of the first embodiment, the rotational speed signal when the receiver 30 is normal is configured by connecting the resistor R1 between the collector and emitter of the transistor Q1 having the open collector configuration in the sensor unit 10. Is set to a voltage obtained by dividing the ground potential or the power supply voltage Vs by the resistors R1 and R2, and the voltage when the signal line 21 or the ground line 23 is disconnected is made equal to the power supply voltage Vs. The presence or absence of disconnection in the line 21 or the ground line 23 can be easily detected with a simple configuration.

(Second Embodiment)
Next, a rotational speed detection device according to a second embodiment of the present invention will be described with reference to FIG. The present embodiment is the same as that of the first embodiment except for the circuit configuration, and the same components are denoted by the same reference numerals, and description thereof is omitted or simplified.

  In FIG. 3, the rotation speed detection sensor 101 of the sensor unit 11 includes a transistor Q1 having a grounded emitter and an open collector configuration that amplifies the detected rotation speed signal and outputs it as a binary pulse signal. In addition, the receiving unit 31 has a configuration in which a light emitting diode on the input side of the photocoupler 301 is connected in series with the power supply line 22 so that the power supply voltage Vs is supplied to the sensor unit 10 through the light emitting diode. It is.

  Next, the operation of this rotational speed detection device will be described. The transistor Q1 is turned on / off according to a rotation speed signal input to the base from the rotation speed detection sensor 101. When turned on, current flows from the power supply voltage Vs of the receiving unit 31 through the pull-up resistor R2, the signal line 21, and the collector and emitter of the transistor Q1, the collector becomes almost the ground voltage (0V), and when turned off, the pull-up resistor R2 Therefore, the collector potential becomes the voltage Vs equal to the power supply voltage.

  In this way, the sensor unit 11 outputs a binary signal of a voltage corresponding to the ground voltage (0 V) or the power supply voltage Vs according to the detected rotation speed. This binary signal is transmitted to the receiving unit 30 via the signal line 21 and is output from the output terminal to the control device 35.

  In the photocoupler 301, since a current flows through the light emitting diode on the input side, the phototransistor on the output side becomes conductive, and the output becomes the ground potential.

  Here, when the power supply line 22 or the ground line 23 is disconnected, no current flows to the input side of the photocoupler 301 that forms part of the power supply line 22, so the output side phototransistor is turned off, and the output has a voltage equal to the power supply voltage. Vs appears. Thereby, it is possible to easily detect that the power line 22 or the ground line 23 is disconnected.

  Therefore, in the rotation speed detection device of the second embodiment, the output side phototransistor of the photocoupler 301 in the normal state is configured by connecting the input side of the photocoupler 301 in series to the power line 22 in the receiving unit 31. Turn it on and turn it off when the power line 22 or ground line 23 is disconnected. As a result, the output voltage of the photocoupler 301 changes, so that the presence or absence of disconnection in the power supply line 22 or the ground line 23 can be easily detected with a simple configuration.

(Third embodiment)
Next, a rotational speed detection device according to a third embodiment of the present invention will be described with reference to FIG. The present embodiment is the same as that of the first embodiment except for the circuit configuration, and the same components are denoted by the same reference numerals, and description thereof is omitted or simplified.

  As shown in FIG. 4, the rotational speed detection device of the present embodiment is a combination of the sensor unit 10 of the first embodiment and the receiving unit 31 of the second embodiment. The receiving unit 31 includes a photocoupler 301 having a power supply line 22 and an input terminal connected in series. The resistor R1 is connected between the collector and the emitter of Q1.

  The operation of the rotational speed detection device is the same as that of the first embodiment described above. In normal times, the voltage obtained by dividing the ground potential or the power supply voltage Vs by the resistors R1 and R2, Vs · R1 / (R1 + R2) Is transmitted from the sensor unit 10 to the receiving unit 31.

  When the signal line 21 or the ground line 23 is disconnected, a voltage equal to the power supply voltage Vs appears at the output terminal of the rotation speed signal of the receiving unit 31 as in the first embodiment, and the signal line 21 and the ground line 23 The presence or absence of disconnection in can be detected.

  When the power supply line 22 or the ground line 23 is disconnected, no current flows to the input side of the photocoupler 301 constituting a part of the power supply line 22, so that the output side phototransistor is turned off, and the voltage Vs equal to the power supply voltage is output. Appears. Thereby, it is possible to detect that the power supply line 22 or the ground line 23 is disconnected.

  Therefore, in the rotational speed detection device of the third embodiment, the rotational speed signal when the receiver 31 is normal is configured by connecting the resistor R1 between the collector and emitter of the transistor Q1 of the open collector configuration in the sensor unit 10. The output terminal voltage is a voltage obtained by dividing the ground potential or the power supply voltage Vs by the resistors R1 and R2, and the voltage when the signal line 21 or the ground line 23 is disconnected is made equal to the power supply voltage Vs. Further, by configuring the input side of the photocoupler 301 in series with the power supply line 22 in the receiver 31, the output side phototransistor of the photocoupler 301 is turned off when the power supply line 22 or the ground line 23 is disconnected. A voltage equal to the voltage Vs appears. As a result, the presence or absence of disconnection in the wiring 20 can be easily detected with a simple configuration.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In the rotational speed detection device of this embodiment, a bipolar transistor is used as the transistor Q1, but a field effect transistor (FET) may be used in an open drain configuration.

It is a figure showing the schematic structure of the bearing device for vehicles in which the rotation speed detecting device concerning a 1st embodiment of the present invention is installed. It is a block diagram which shows the electrical schematic structure in the rotational speed detection apparatus of 1st Embodiment. It is a block diagram which shows the electrical schematic structure in the rotational speed detection apparatus of 2nd Embodiment. It is a block diagram which shows the electrical schematic structure in the rotational speed detection apparatus of 3rd Embodiment. It is a figure which shows schematic structure of the bearing apparatus for vehicles by which the conventional rotational speed detection apparatus is installed. It is a block diagram which shows the electrical schematic structure of the conventional rotational speed detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 11 Sensor part 20 Wiring 21 Signal line 22 Power supply line 23 Ground line 30, 31 Receiving part 101 Rotation speed detection sensor 301 Photocoupler Q1 Transistor R1, R2, R8 Resistance

Claims (4)

A sensor unit including a rotation speed sensor that outputs a binary rotation speed signal in response to ON / OFF of a transistor having an open collector or open drain configuration, a signal line that transmits the rotation speed signal, and a power supply voltage to the sensor unit A rotational speed detection device comprising: a wiring composed of a power supply line and a ground line; and a receiving unit that receives and outputs the rotational speed signal by connecting a receiving end connected to the signal line of the wiring with a pull-up resistor. There,
The sensor unit includes a resistor connected between the output terminal of the transistor and the ground,
A rotation speed detection device that detects disconnection of the signal line or the ground line based on the potential of the signal line in the receiving unit. A sensor unit including a rotation speed sensor that outputs a binary rotation speed signal in response to ON / OFF of a transistor having an open collector or open drain configuration, a signal line that transmits the rotation speed signal, and a power supply voltage to the sensor unit A rotational speed detection device comprising: a wiring composed of a power supply line and a ground line; and a receiving unit that receives and outputs the rotational speed signal by connecting a receiving end connected to the signal line of the wiring with a pull-up resistor. There,
The receiver includes a photocoupler having an input terminal connected in series to the power line,
A rotation speed detection device that detects disconnection of the power supply line or the ground line based on the output of the photocoupler. A sensor unit including a rotation speed sensor that outputs a binary rotation speed signal in response to ON / OFF of a transistor having an open collector or open drain configuration, a signal line that transmits the rotation speed signal, and a power supply voltage to the sensor unit A rotational speed detection device comprising: a wiring composed of a power supply line and a ground line; and a receiving unit that receives and outputs the rotational speed signal by connecting a receiving end connected to the signal line of the wiring with a pull-up resistor. There,
The sensor unit includes a resistor connected between the output terminal of the transistor and the ground, and the receiving unit includes a photocoupler in which an input terminal is connected in series to the power line.
A rotational speed detection device that detects disconnection of the wiring based on a potential of the signal line and presence / absence of an output of the photocoupler in the receiver.   The said rotational speed sensor is installed in the vicinity of the vehicle bearing apparatus, The rotational speed detection apparatus in any one of Claims 1-3 characterized by the above-mentioned.

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