JPH09331631A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a braker from being opened unnecessarily during the operating state. SOLUTION: When a key switch 104 is closed, current flows in a relay coil 107 and a relay switch 106 is closed and then power is supplied to a load L from a battery 101. When a specified period of time which is determined by a delay circuit 117 passes after the key switch is closed, a transistor 116 is turned on and current flows in a relay coil 112 and thereby a relay switch 111 is opened. By this, current stops flowing in a braker 113.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for supplying electric power of a battery to a load via an operation switch.

[0002]

2. Description of the Related Art Conventionally, various power supply devices have been used in equipment such as working machines equipped with a battery. FIG. 2 is a circuit diagram showing a conventional power supply device, which is an example used in an agricultural machine.

In FIG. 2, the operating state is entered by closing the key switch 4 which is an operation switch. As a result, the positive terminal of the battery 1 → the fusible link 2 → the resistor 10 → the breaker 11 → the 30th terminal of the key switch 4 →
A current flows in the order of the AC terminal of the key switch 4, the relay coil 13 of the relay drive circuit 12, and the ground. Therefore,
The attraction force of the relay coil 13 acts to switch the relay switch 9 to the closed state. Electric power is supplied to various loads such as the solenoid 7, the air conditioner 8 and the like.

At this time, a current always flows through the series circuit composed of the resistor 10 and the breaker 11. However, since the current is limited by the resistor 10, the current flowing through this series circuit is very small, and most of them are the relay switch 9 Will flow through. The original power supply is performed in this state.

On the other hand, when the agricultural work machine is in a non-operating state stored in a barn or the like (when the key switch 4 is off)
For example, consider a case where the wire harness 16 connecting the No. 30 terminal of the key switch 4 and the No. 30 terminal of the safety unit 3 is bitten by a mouse or the like and the coating is damaged and short-circuited through the body ground. .

In this case, electricity is always supplied from the positive terminal of the battery 1 to the 30th terminal of the key switch 4 through the series circuit of the resistor 10 and the breaker 11, so that the short circuit occurs and the positive terminal of the battery 1 → The fusible link 2 → resistor 10 → breaker 11 → grounded closed circuit is formed, and a large current flows through the breaker 11. As a result, the breaker 11 is instantly opened so that the wire harness 16 is not burned. Therefore,
The occurrence of fire or the like due to burnout of the wire harness 16 is prevented in advance. Then, if the short-circuited portion in the wire harness 16 is repaired and the breaker 11 is returned to the original state, the normal state can be easily restored. As described above, even if a short circuit accident occurs in the wire harness 16, it is possible to reliably prevent the wire harness 16 from being burnt out and eventually the fire from occurring, by instantaneously opening the breaker 11.

[0007]

In the above power supply device, the breaker 1 is used when the load is large or when the contact resistance between the relay switch 9 contacts increases due to long-term use.
If the current flowing in 1 increases and the capacity of the breaker 11 is smaller than the current flowing at this time, the breaker 11 is opened even during normal operation. Therefore, there is a problem that the breaker needs to be reset to the closed position every time when the non-operating state is changed to the operating state again, and the operation becomes complicated. An object of the present invention is to provide a power supply device that can prevent the breaker from being unnecessarily opened.

[0008]

A power supply device of the present invention is a power supply device for supplying an output of a battery to a load through an operation switch, between an output terminal of the battery and an input side terminal of the operation switch. A series circuit composed of a normally open first switch and a normally closed second switch connected in parallel to the first switch, and the first switch in response to a closing operation of the operation switch. And a second switch driving means for driving the second switch to an open state after a lapse of a predetermined time in response to a closing operation of the operation switch. There is.

When the operation switch is closed, the first switch driving means drives the first switch to the closed state. As a result, electric power is supplied from the battery to the load via the first switch and the operation switch. At this point, power is also supplied to the load from the battery via the second switch and the breaker. After a lapse of a predetermined time from the closing operation of the operation switch, the second switch driving means drives the second switch to the open state, whereby no current flows through the breaker. Therefore, in the steady operating state, the first
Electric power is supplied to the load through the switch and the operation switch.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a power supply device used in an agricultural machine according to an embodiment of the present invention.

In FIG. 1, the positive terminal side of the battery 101 whose negative terminal side is grounded is connected to the B terminal of the safety unit 103 housed in the case via the fusible link 102. The E terminal of the safety unit 103 is grounded. The 30th terminal and the AC terminal of the safety unit 103 are connected to the input side terminal and the output side terminal of the key switch 104, respectively. Key switch 104
The output side terminal of the through the fusible link 105,
It is connected to a load L composed of a lamp or the like.
Although only one fusible link 105 and one load L are shown, a plurality of various loads can be connected as in the example shown in FIG.

On the other hand, the B terminal of the safety unit 103 has the first
It is connected to the 30th terminal through a normally open relay switch 106 as a switch, and the E terminal is a relay coil 107 as a first switch driving means for controlling the opening / closing of the relay switch 106 and a diode 1 for preventing backflow.
08 and a reverse circuit 109 connected in series to the parallel circuit, and is connected to the AC terminal.

A series circuit composed of a normally closed relay switch 111 as a second switch and a breaker 113 is connected in parallel to the relay switch 106. Also,
A backflow prevention diode 11 is provided between terminal 30 and ground.
4. Relay coil 112 and backflow prevention diode 115
And a parallel circuit, and a transistor 116 are connected in series. The relay switch 111 and the relay coil 112 form a relay circuit 110.

The base of the transistor 116 is a resistor 12
It is connected to the connection point of the diodes 108 and 109 via 0. A parallel circuit including a discharging resistor 118 and a capacitor 119 is connected between the base of the transistor 116 and the ground. Capacitor 119 and resistor 120
The delay circuit 117 is composed of a time constant circuit composed of.
The relay coil 112, the transistor 116, and the delay circuit 117 form second switch driving means.

The operation of the embodiment configured as described above will be described below. The operating state is entered by closing the key switch 104. As a result, a current flows in the order of positive terminal of battery 101 → fusible link 102 → B terminal → relay switch 111 → breaker 113 → key switch 104 → diode 109 → relay coil 107 → ground. Therefore, the attraction force of the relay coil 107 acts and the relay switch 106 is switched to the closed state. Therefore, the positive terminal of the battery 101 → fusible link 102 → relay switch 106 → key switch 1
Electric power is supplied to the load L via 04 → fusible link 105.

At the same time, since a current flows through the resistor 120 to the capacitor 119, the capacitor 119
Charging is started with a time constant determined by the resistor 120 and the capacitor 119. When the capacitor 119 is charged to a predetermined voltage, that is, when the constant delay time determined by the time constant elapses, the transistor 116 is turned on. As a result, a current flows through the relay coil 112 via the diode 114, so that the relay switch 111
Is opened and this state is maintained.

In the steady operation state, power is supplied to the load L as described above, but since the relay switch 111 is maintained in the open state, no current flows through the breaker 113. Therefore, even if the load L increases or the contact resistance between the contacts of the relay switch 106 increases due to long-term use, the breaker 113 does not unnecessarily switch to the open state.

On the other hand, when the farming machine is stored in a barn or the like in a non-operating state (when the key switch 104 is in an off state), for example, the wire harness 16 is bitten by a mouse or the like, and the coating is damaged. Consider the case of shorting through the body ground.

In this case, the key switch 1 is connected through a series circuit composed of the relay switch 111 and the breaker 113.
Electricity always comes from the positive terminal of the battery 101 up to the No. 30 terminal of No. 04.
01 positive terminal → relay switch 111 → breaker 113
→ A closed circuit that is grounded is formed, and a large current flows through the breaker 113. As a result, the breaker 113 is instantly switched to the open state, so that the wire harness 16 is not burned, and fire or the like due to burning of the wire harness 16 is prevented. Then, the short circuit portion in the wire harness 16 is repaired, and the breaker 11
If 3 is returned to the original state, it will easily return to the normal state.

As described above, according to the present embodiment, in the power supply device for supplying the output of the battery 101 to the load L via the key switch 104, the battery 10
1 is a normally open relay switch 106 connected between the output terminal of the key switch 104 and the input side terminal of the key switch 104, and a series circuit including a normally closed relay switch 111 and a breaker 113 connected in parallel to the relay switch 106. And the relay switch 106 in response to the closing operation of the key switch 104.
A relay coil 107 that drives the relay switch 111 to a closed state, and a relay coil 112 that drives the relay switch 111 to an open state after a predetermined time has elapsed in response to a closing operation of the key switch 104,
Since the delay circuit 117 and the transistor 116 are provided, no current flows through the breaker 113 in the operating state. Therefore, even if the load L increases or the contact resistance of the relay switch 106 increases, the breaker 113 increases. 113 does not unnecessarily switch to the open state.

Further, since the relay switch 111 is controlled to be opened in a predetermined time after the key switch 104 is closed, the relay switch 111 is surely opened after the relay switch 106 is closed. There is an effect that it becomes possible to.

In this embodiment, the time constant circuit composed of the resistor and the capacitor is used to generate the delay time, but it is also possible to use the timer circuit using the digital circuit. Further, although the relay switch is used as the switch, a semiconductor switch may be used depending on the current capacity. Furthermore, although an example of an agricultural machine has been described in the present embodiment, the present invention can be applied to various equipment including a battery and an operation switch, such as a construction machine and an automobile.

[0023]

According to the present invention, the breaker can be prevented from being unnecessarily opened. Further, there is an effect that the second relay switch 111 can be surely opened after the first relay switch is closed.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional power supply device.

[Explanation of symbols]

101 ... Battery 104 ... Key switch as operation switch 106 ... Relay switch as first switch 107 ... Relay coil as first switch driving means 111 ... Relay switch as second switch 112 ... Relay coil which constitutes second switch driving means 113 ... Breaker 116 ... Transistor which constitutes second switch driving means 117 ... Delay circuit which constitutes second switch driving means L ... load

Claims (1)

[Claims] 1. A power supply device for supplying an output of a battery to a load via an operation switch, a normally open first switch connected between an output terminal of the battery and an input side terminal of the operation switch, A series circuit connected in parallel to the first switch and including a normally closed second switch and a breaker, and the first circuit in response to a closing operation of the operation switch.
First switch driving means for driving the switch to a closed state,
A power supply device, comprising: a second switch driving unit that drives the second switch to an open state after a predetermined time has elapsed in response to a closing operation of the operation switch.