JP2004007889A - Charge lamp circuit for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a circuit in a charge lamp circuit. <P>SOLUTION: The charge lamp circuit comprises: a monitor-internal circuit 7 that feeds a voltage Vacc to an alternator 3 in a monitor device 1 to which a charge lamp 4 is connected when the alternator 3 does not operate or the generated voltage is in a low level, and stops the supply of the voltage when the generated voltage of the alternator becomes high; a voltage detecting circuit 8 that detects the voltage of the monitor-internal circuit; and a control unit 9 that determines whether a voltage detected by the voltage detecting means is lower than a preset voltage and outputs a command for lighting/extinguishing the charge lamp based on the determination. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a circuit for a charge lamp in a construction machine such as a hydraulic shovel.
[0002]
[Prior art]
Generally, a construction machine such as a hydraulic excavator is provided with a monitor device provided with various instruments, an alarm lamp, and the like. One of the alarm lamps provided in the monitor device is a charge lamp. The charge lamp is configured to be turned on when the alternator is not operating when the engine is stopped or when the generated voltage is low due to a decrease in the performance of the alternator, and is turned off when the generated voltage of the alternator is high. However, as a circuit for such a charge lamp, a circuit as shown in FIG. 3 has been conventionally known.
In the circuit shown in FIG. 3, 1 is a monitoring device provided with a charge lamp 4, 3 is an alternator, 6 is a battery, and 14 is a safety relay circuit (a relay having a function of preventing re-entry of a starter motor during engine rotation). R is a circuit connecting the alternator 3, the safety relay circuit 14, and the monitor device 1. In this circuit, when the key switch is turned on from OFF to close the switch contact ACC, the battery The voltage (12 V) flows through the safety relay circuit 15 to the line G, flows from the line G to the field coil 12 of the alternator 3, and supplies an initial exciting current. The current supplied to the field coil 12 flows to the ground 13 via the IC regulator 11 provided in the alternator 3, so that the line G is at the ground level. Further, when the key switch is turned on, the battery voltage is also supplied to the monitor device 1 to set the first and second monitor device voltages Vacc (12 V) and Vcc (5 V). , The second monitor device voltage Vcc flows to the line G via the input interface 15 and the A terminal. Thus, the voltage output from the input interface 15 to the inverter IC 16 becomes LOW, but the output of the inverter IC 16 becomes HIGH when the input is LOW, and the transistor 17 is turned ON when the output of the inverter IC 16 is HIGH. The voltage from the first monitor device voltage Vacc is supplied to the charge lamp 4, and the charge lamp 4 is turned on.
On the other hand, since the alternator 3 is operating after the engine is started, the voltage (14 V) generated by the alternator 3 is output to the line G. As a result, the potential of the line G becomes higher than the potential of the monitor device 1, so that the input interface 15 supplies the second monitor device internal voltage Vcc to the inverter IC 16. When the input is HIGH, the output of the inverter IC 16 is LOW. At this time, the transistor 17 is set to be OFF, so that the voltage from the first monitor device voltage Vacc is applied to the charge lamp 4. No charge is supplied, and the charge lamp 4 is turned off.
Further, when the performance of the alternator 3 decreases and the output voltage to the line G decreases, the voltage Vcc in the second monitor flows to the line G and the charge lamp 4 is turned on, as in the case of the supply of the initial excitation current described above. Thus, the alternator 3 is configured to be able to warn of a power generation failure.
[0003]
[Problems to be solved by the invention]
By the way, some key switches have an anti-start lock function (a function in which once the key cylinder is turned to the START position, it cannot be returned to the START position without returning to the OFF position). In addition, a safety relay circuit as a function of preventing the starter motor from re-entering becomes unnecessary. However, in the conventional circuit, a safety relay circuit is used as a circuit for supplying an initial excitation current to the alternator when the key switch is turned on and for turning on and off the charge lamp. For this reason, even with a key switch having an anti-start lock function, the safety relay circuit cannot be omitted, and there is a problem that the simplification of the circuit is hindered. there were.
[0004]
[Means for Solving the Problems]
The present invention has been made in view of the above circumstances, and has been created with the object of solving these problems, and a monitor device circuit to which a charge lamp for notifying the power generation state of the alternator is connected, When the alternator is not operating or the generated voltage is low, the supply voltage from the battery is supplied to the alternator via a resistor, while when the generated voltage of the alternator increases, the monitor internal circuit stops the voltage supply to the alternator. Voltage detecting means for detecting the voltage of the monitor internal circuit; determining whether or not the voltage detected by the voltage detecting means is equal to or lower than a preset voltage; and lighting the charge lamp based on the determination. And a control unit for outputting a light-off instruction.
In this manner, the supply of the initial excitation current to the alternator and the turning on / off of the charge lamp can be performed by a circuit provided in the monitor device, which contributes to simplification of the circuit. it can.
In this device, the supply of voltage from the battery to the circuit for the monitor device is performed based on the closing of the key switch, but if the key switch has an anti-start lock function, the safety relay circuit can be omitted. Can be particularly useful.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a monitor device arranged on a driver's seat 2 of a hydraulic shovel. The monitor device 1 is provided with various instruments and alarm lamps. First, a charge lamp 4 for notifying the power generation state of the alternator 3 mounted on the hydraulic excavator is provided.
[0006]
Now, FIG. 2 shows a circuit of a part of the monitor device 1 to which the present invention is concerned. In FIG. 2, B is a terminal provided on the monitor device 1, and the B terminal is a key switch 5. It is connected to the battery 6 via the switch contact ACC. Then, by closing the switch contact ACC of the key switch 5, the voltage (12V) of the battery 6 is input to the monitor device 1 from the B terminal so that the monitor device voltage (12V) Vacc is set. It is configured.
[0007]
Here, the key switch 5 is inserted from a OFF position to an ON position by inserting a key (not shown), thereby closing a switch contact ACC to energize the electric system of the hydraulic excavator, and further from the ON position to the START position. As a result, a switch contact ST (not shown) is closed and a starter motor (not shown) is driven, whereby the engine is started. Further, the key switch 5 has a so-called anti-start lock function that, when the key is turned to the START position, cannot be returned to the START position unless the key is returned to the OFF position once, thereby preventing re-entry of the starter motor during engine rotation. You can do it.
[0008]
The monitor device internal voltage Vacc is connected to an A terminal of the monitor device 1 via a monitor internal circuit 7 provided with a resistor R and a diode D. The A terminal is connected to the L terminal of the alternator 3 via the line Y.
[0009]
Reference numeral 8 denotes a voltage detection circuit, which is configured to detect a voltage of the monitor internal circuit 7 from the resistor R to the diode D. The voltage V detected by the voltage detection circuit 8 is input to a control unit (CPU) 9.
[0010]
The control unit 9 receives the detection voltage V from the voltage detection circuit 8 and determines whether or not the detection voltage V is equal to or lower than a preset pressure Vs (for example, 7 V). When the detection voltage V is equal to or lower than the set pressure Vs (V ≦ Vs), a lighting signal of the charge lamp 4 is output to the output interface 10. When the detection voltage V exceeds the set pressure Vs (V> Vs), a signal to turn off the charge lamp 4 is output to the output interface 10. Here, the set pressure Vs is set so as to be smaller than the monitor device internal voltage Vacc and larger than the initial excitation voltage Vm of the alternator 3 described later (Vm <Vs <Vacc).
[0011]
On the other hand, the alternator 3 is driven by an engine to supply generated power to various electric devices and to charge the battery 6, and the alternator 3 keeps a generated voltage constant by a semiconductor circuit. An IC regulator 11 is provided. Reference numeral 12 denotes a field coil of the alternator 3, and the field coil 12 is connected to the line Y via an L terminal.
[0012]
Now, when the operation of the hydraulic excavator is started, first, when the key switch 5 is turned from the OFF position to the ON position, the battery voltage is input to the monitor device 1 and the monitor device voltage Vacc is set. The internal voltage Vacc flows through the resistor R, the diode D, and the A terminal of the monitor internal circuit 7 to the line Y, and further from the line Y to the field coil 12 via the L terminal of the alternator 3 for initial excitation. Supply current. This initial exciting current flows from the field coil 12 to the ground 13 through the IC regulator 11. At this time, the voltage detection circuit 8 in the monitor device 1 detects the initial excitation voltage Vm (for example, 1 V) whose voltage has dropped by the resistor R disposed in the monitor internal circuit 7, and the initial excitation voltage Vm is as described above. Is lower than the set voltage Vs. Thus, the control unit 9 outputs a charge lamp lighting signal, and the charge lamp 4 is turned on.
[0013]
Next, when the key switch 5 is turned from the ON position to the START position and the engine is driven, the alternator 3 operates to generate a specified voltage (about 14 V) in accordance with the driving of the engine. The voltage generated by the alternator 3 is output from the L terminal to the line Y. If the potential of the line Y becomes higher than the potential of the monitor device 1, the monitor device voltage Vacc flows from the A terminal to the line Y. Therefore, the voltage detection circuit 8 detects the voltage Vacc in the monitor device. The voltage Vacc in the monitor device is higher than the set voltage Vs as described above, so that the charge lamp extinguishing signal is output from the control unit 9 and the charge lamp 4 is extinguished.
[0014]
On the other hand, if any abnormality occurs in the power generation system such as a decrease in the performance of the alternator 3 and the alternator 3 does not generate the specified voltage, the voltage output to the line Y decreases. When the potential of the line Y becomes lower than the potential of the monitor device 1, the monitor device voltage Vacc flows to the line Y via the monitor internal circuit 7. At this time, the voltage detection circuit 8 detects the voltage flowing from the monitor internal circuit 7 to the line Y. When the detected voltage V becomes smaller than the set voltage Vs, the control unit 9 outputs a charge lamp lighting signal and charges the battery. The lamp 4 lights up.
[0015]
In the apparatus configured as described above, the monitor device 1 supplies the monitor device voltage Vacc to the alternator 3 via the resistor R while the alternator 3 is not operating or the generated voltage is low, while the alternator 3 A monitor internal circuit 7 for stopping supply of voltage to the alternator 3 when the generated voltage of the monitor 3 becomes high is provided. The voltage of the monitor internal circuit 7 is detected by a voltage detection circuit 8, and the detected voltage is set. Based on the determination as to whether the voltage is equal to or lower than the voltage, the controller 9 outputs a command signal for turning on / off the charge lamp 4.
As a result, the supply of the initial excitation current to the alternator 3 and the turning on / off of the charge lamp 4 can be performed by a circuit provided in the monitor device 1 without using a safety relay circuit as in the related art. Therefore, if the key switch 5 has an anti-start lock function, the safety relay circuit can be omitted, and the circuit can be simplified.
[Brief description of the drawings]
FIG. 1 is a plan view of a hydraulic excavator.
FIG. 2 is a circuit for a charge lamp showing an embodiment of the present invention.
FIG. 3 is a circuit for a charge lamp showing a conventional example.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 monitor device 3 alternator 4 charge lamp 5 key switch 6 battery 7 monitor internal circuit 8 voltage detection circuit 9 control unit

Claims (2)

A monitor device circuit to which a charge lamp for notifying the power generation state of the alternator is connected,
When the alternator is not operating or the generated voltage is low, the supply voltage from the battery is supplied to the alternator via a resistor, while when the generated voltage of the alternator increases, the monitor internal circuit stops the voltage supply to the alternator. ,
Voltage detection means for detecting the voltage of the monitor internal circuit;
A control unit for determining whether or not the voltage detected by the voltage detection means is equal to or lower than a preset voltage, and outputting a charge lamp on / off command based on the determination. Circuit for charge lamps in construction machinery. 2. The charge in a construction machine according to claim 1, wherein the voltage supply from the battery to the monitor device circuit is performed based on closing of a key switch, and the key switch has an anti-start lock function. Lamp circuit.

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