JP2010064564A - Instrument drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument drive device which protects a circuit of a control unit when an overcurrent is supplied and reduces a burden of repair work. <P>SOLUTION: The instrument drive device includes instruments 2, 3, which indicate vehicle information, and the control unit 1, which is provided separately from the instruments 2, 3. The control unit 1 includes: an instrument power supply line L1, which supplies electric power to the instruments 2, 3; a first switching means TR1, which is provided on the instrument power supply line L1 to turn ON/OFF of the power supply to the instruments 2, 3; a second switching means TR2, which switches ON/OFF of the first switching means; a temperature detection means TH1, which detects the temperature of the first switching means TR1; and a control means 1a, which switches off the second switching means TR2 and turns off the power supply to the instruments 2, 3 when the first switching means TR1 is judged to have reached a predetermined temperature based on a detection result by the temperature detection means TH1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an instrument driving device provided separately from a vehicle combination meter.

  Conventionally, it is called an aftermeter that can be attached to a dashboard, an instrument panel (instrument panel), etc., apart from an existing combination meter in which a speedometer, tachometer, thermometer and fuel gauge are housed in a case body. Instrument is known. As this after meter, for example, a single analog display unit is housed in a case, and there is a meter or a light emitting display for displaying single vehicle information (for example, engine speed) of the vehicle. There are instruments that digitally display. Such an instrument is often mounted on a racing vehicle running on a circuit racetrack or the like, a supercharger, a turbo-equipped vehicle, or the like. These types of instruments include a tachometer that monitors the engine speed, an intake pressure gauge (boost meter) that monitors the boost pressure of the engine, an exhaust thermometer that monitors the exhaust gas exhaust temperature, and the engine oil temperature. There are oil temperature gauges, oil pressure gauges that monitor engine oil pressure, and fuel pressure gauges that monitor fuel pressure.

  Further, the applicant of the present application has proposed a meter driving device disclosed in Patent Document 1 as a driving device for an aftermeter that is assumed to be arranged in plural. The instrument driving device proposed in Patent Document 1 includes an input port that enables input of a plurality of state signals according to vehicle information, and a single control for obtaining each measurement value according to the plurality of state signals A unit (control unit) is provided, and the control unit and each instrument are communicated by serial data generated by the control unit. It is possible to simplify and attach the respective instruments without damaging the beauty of the dashboard and instrument panel.

In the after-meter driving device, the control unit is provided with a meter power supply line connected to a battery power source to supply power to the meter, and the power is supplied to each meter via the control unit. Since it is not necessary to wire a power supply line connected to the battery power source for each instrument, it is possible to simplify the mounting operation and improve the aesthetics.
JP 2000-18974 A

  The instrument power supply line provided in the control unit may be supplied with overcurrent due to, for example, a failure of a circuit of each instrument, a short circuit of a meter harness connected to the instrument, and the like. Since there is a problem that the circuit breaks down, the heat generation of the chip coil on the instrument power supply line is detected with a thermal fuse in the past, and the thermal fuse is blown by overheating due to overheating of the circuit, causing a circuit failure due to overcurrent Was preventing. However, in the conventional method, when an overcurrent is supplied, it is necessary to replace the thermal fuse in the control unit in addition to repairing the cause of the overcurrent supply mainly generated on the connected instrument side. In addition, since the repair work becomes complicated, there is a problem that there is room for further improvement as the control unit which is supposed to supply power to a plurality of instruments.

  In view of the above-mentioned problems, the present invention further improves the after-meter driving device provided with a control unit for supplying power to the instrument, protects the circuit of the control unit when an overcurrent is supplied, and performs repair work. An object of the present invention is to provide an instrument driving device capable of reducing the load.

  In order to solve the above problems, the present invention inputs a plurality of state signals indicating vehicle information provided separately from the meter for displaying vehicle information and the vehicle information, and each of the vehicle information based on each state signal. A control unit that obtains measurement values, converts each measurement value into serial data, and transmits the serial data to the instrument, wherein the control unit supplies power to the instrument Instrument power supply line, first switch means provided on the instrument power supply line for turning on / off power supply to the instrument, and second switch for switching on / off the first switch means Means, a temperature detecting means for detecting the temperature of the first switch means, and based on a detection result by the temperature detecting means, it is determined that the first switch means has reached a predetermined temperature. Switching to the second off switch means and characterized in that it comprises a control means for turning off the power supply to the instrument when that.

  In addition, the meter includes a transmission member for supplying power to another meter.

  Further, the first switch means is composed of a transistor.

  In particular, the present invention relates to a driving device for a meter provided separately from a vehicle combination meter, and can protect the circuit of the control unit when an overcurrent is supplied, and can reduce the load of repair work. It will be.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The overall configuration of the instrument driving apparatus will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the instrument driving apparatus mainly includes a control unit (control unit) 1, a hydraulic gauge (instrument) 2, and a fuel pressure gauge (instrument) 3.

  The control unit 1 is provided separately from the oil pressure gauge 2 and the fuel pressure gauge 3, and includes a control means 1a composed of a microcomputer housed in a single case body.

  The control means 1a is processed by the A / D converter that inputs each status signal indicating vehicle information, a CPU that executes a predetermined processing operation program, a ROM that stores the processing operation program and the like, and the CPU. RAM that temporarily stores data, a parallel / serial converter (P / S converter) that converts parallel data into serial data, and an EEPROM or backup RAM that stores various settings in a nonvolatile manner The storage unit includes a transmission unit that transmits the serial data at a predetermined cycle. When the state signals indicating the vehicle information are input, the control unit 1a performs a predetermined calculation process according to the state signals and calculates each measurement value of the vehicle information. Further, the control means 1a converts the model code for identifying the model of the instrument and the parallel data as the respective measured values into serial data, and the hydraulic meter 2 and the fuel pressure gauge 3 will be described later via the wiring members 4a and 4b. To the control means. The wiring member 4a is a wiring member including a multiplex transmission communication line for transferring serial data from the control unit 1, a power supply line for supplying power, a ground line, and the like. One end is connected to the control unit 1 and the other end is a hydraulic meter. 2 is connected to the control means. The wiring member 4b has the same configuration as that of the wiring member 4a, and one end is connected to the oil pressure gauge 2 and the other end is connected to the fuel pressure gauge 3. Therefore, in the present embodiment, transmission of the serial data from the control unit 1 is performed in the order of the hydraulic pressure gauge 2 → the fuel pressure gauge 3.

  As shown in FIG. 2, the oil pressure gauge 2 is an analog type instrument in which a control means 2 a and an analog type display unit 2 b are housed in a case body, and displays oil pressure as vehicle information. is there.

  The control means 2a comprises a microcomputer, receives the serial data transmitted by the control unit 1, and causes the display unit 2b to perform a display operation based on the serial data. Further, the control means 2a transfers the serial data to the control means 3a of the fuel pressure gauge 3 via the wiring member 4b.

  As shown in FIG. 2, the fuel pressure gauge 3 is an analog meter in which a control means 3a and an analog display section 3b are housed in a case body, and displays fuel pressure as vehicle information. is there.

  The control means 3a is composed of a microcomputer, and receives the serial data transmitted from the control unit 1 via the control means 2a of the hydraulic gauge 2, and displays the display unit 3b based on the serial data.

  FIG. 3 illustrates a part of the electronic circuit of the control unit 1. The control unit 1 has a meter power supply line L1 for supplying power to the meters 2 and 3. The meter power supply line L1 has one end connected to the battery power source Vb and the other end connected to the hydraulic meter 2. Further, the oil pressure gauge 2 is connected to the fuel pressure gauge 3. Accordingly, power supply from the control unit 1 is performed in the order of the hydraulic pressure gauge 2 → the fuel pressure gauge 3. CN1 to CN6 denote connectors (transmission members). The instrument power supply line L1 is provided with a diode D1 for protecting the reverse connection of the power supply and a first transistor (first switch means) TR1 for turning on / off the power supply, and also for the electrolysis for stabilizing the power supply. A capacitor C1 is connected.

  The first transistor TR1 can be an NPN transistor, for example, and is configured to be able to switch on / off the power supply from the battery power supply Vb connected to the collector side to each of the meters 2 and 3 connected to the emitter side. The The base side of the first transistor TR1 is connected to the Zener diode ZD1 for power supply surge protection and the collector side of the second transistor (second switch means) TR2. R3 is a current limiting resistor that limits the amount of current to the first transistor TR1.

  For example, a PNP transistor can be used as the second transistor TR2, a battery power source Vb is connected to the emitter side, a base side of the first transistor TR1 is connected to the collector side, and the first transistor TR1 is switched on / off. It is configured to be possible. The control means 1a is connected to the base side of the second transistor TR2, and is turned on / off by the control means 1a. R1 and R2 are current limiting resistors that limit the amount of current to the second transistor TR2.

  A thermistor (temperature detection means) TH1 is provided in the vicinity of the first transistor TR1. The thermistor TH1 detects the temperature of the first transistor TR1 and is connected to the control means 1a. The control means 1a reads the voltage divided by the thermistor TH1 and the resistor R4, thereby measuring the temperature of the first transistor TR1.

  When it is determined that the temperature of the first transistor TR1 has reached a predetermined temperature based on the detection result by the thermistor TH1, the control means 1a switches the second transistor TR2 off. As a result, the first transistor TR1 is switched off, and the power supply to the meters 2 and 3 is turned off (stopped). In order to convert the temperature of the thermistor TH1 into a voltage, it is possible to configure a control means for switching on / off of power supply using a comparator or the like only with a circuit without using a microcomputer.

  The instrument driving apparatus according to this embodiment can detect an overcurrent by detecting the temperature of the first transistor TR1 that generates heat according to the supplied current value by the thermistor TH1, and the overcurrent can be supplied. When detected, the control unit 1a can turn off the power supply to the meters 2 and 3 to protect the circuit of the control unit when the overcurrent is supplied. Further, since the power supply is turned off by switching on / off the second transistor TR2 by the control means 1a, the control unit 1 itself does not need repair work, and the load of repair work after overcurrent supply is reduced. It becomes possible. Further, by using the first transistor TR1 as the first switch for switching on / off of the power supply, the overcurrent can be detected by the thermistor TH1 having a simple circuit configuration, and the overcurrent protection and the work load can be performed by a simple method. Can be reduced.

  In addition, by providing connectors CN4 and CN6 for supplying power to the other instruments in each of the instruments 2 and 3, a power supply line for connecting the battery power supply Vb for each instrument even when a plurality of instruments are arranged. It is possible to simplify the installation work and improve the aesthetics around the instrument panel.

The block diagram which shows the structure of the drive device of the meter of embodiment of this invention. The block diagram which shows the structure of the instrument in the drive device of an instrument same as the above. The figure which shows the circuit structure of the drive device of an instrument same as the above.

Explanation of symbols

1 Control unit (control unit)
1a Control means 2 Hydraulic gauge (instrument)
2a Control means 2b Display unit 3 Fuel pressure gauge (instrument)
3a Control means 3b Display part L1 Instrument power supply line TH1 Thermistor (temperature detection means)
TR1 first transistor (first switch means)
TR2 Second transistor (second switch means)
Vb battery power

Claims (3)

An instrument for displaying vehicle information, and a plurality of state signals that are provided separately from the instrument and that indicate vehicle information are input, and each measurement value of the vehicle information is obtained based on each state signal, and each measurement value is serial data A control unit that converts the serial data to the instrument and converts the serial data to the instrument,
The control unit includes a meter power supply line for supplying power to the meter, a first switch means provided on the meter power supply line for turning on / off the power supply to the meter, and the first Second switch means for switching on / off of the switch means, temperature detection means for detecting the temperature of the first switch means, and the first switch means has a predetermined temperature based on a detection result by the temperature detection means. And a control means for turning off the second switch means to turn off the power supply to the instrument when it is determined that the value has been reached. The instrument driving device according to claim 1, wherein the instrument includes a transmission member for supplying power to another instrument. 2. The instrument driving apparatus according to claim 1, wherein the first switch means comprises a transistor.

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