JP3349448B2 - Battery charging circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging circuit applied to a machine that can be driven by either an electric motor or an engine.

[0002]

2. Description of the Related Art Conventionally, in a construction machine which can be driven by either an electric motor or an engine, a method of charging a battery by charging the battery with a voltage generated by an alternator mounted on the engine only when the engine is driven is known. General.

On the other hand, construction machines which can be driven by either the electric motor or the engine mainly drive the electric motor. The engine is driven when the power of the electric motor is not supplied or when the electric motor is out of order. Is done.

[0004] Therefore, the battery is not charged in the normal operation by driving the electric motor, and the battery is discharged unless the engine is driven for a long time, so that the engine may not be driven when necessary.

[0005]

When the battery is discharged, it is necessary to start it by wiring with a jumper cable using another construction machine or to replace the battery, which is troublesome. Workability is not good either.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and in a construction machine that can be driven by either an electric motor or an engine, a battery can be charged at each drive, thereby preventing inconvenience due to battery discharge. The purpose is to:

[0007]

Means for Solving the Problems The invention described in claim 1, an electric motor driven by an AC power source, and Ba
In either drivable machine engine is started by Tteri, a generator for outputting DC driven by the engine during engine drive, and when the engine driving to charge the battery charging circuit by direct current supplied from the generator a battery charging circuit which includes an electric motor drive-time charging circuit for charging the battery is converted into direct current alternating current from ac power supply when the electric motor drive.

Thus, the battery can be charged not only at the time of driving the engine where the generator functions but also at the time of driving the electric motor where the generator does not function.

According to a second aspect of the present invention, in the battery charging circuit of the first aspect, an AC / DC converter for converting AC to DC, and an AC / DC converter for converting DC from a generator when the engine is driven. And an interlock circuit for supplying a battery without supplying the battery.

[0010] With this interlock circuit, when charging the battery, there is no possibility that the generated voltage from the generator is applied to the AC / DC converter.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS.

The circuit shown in FIG. 1 corresponds to a construction machine driven mainly by an electric motor but can also be driven by an engine if necessary. The electric motor is driven by an AC circuit, and the engine is a DC motor. Driven by a circuit.

An AC power supply 11 is connected to an AC circuit 13 for an electric motor via a circuit breaker (NFB) 12, and is further connected to an AC / DC converter 14 for converting AC into DC. Circuit 15 is connected.

The DC circuit 15 includes a coil 16 of the relay R1,
Relay R2 coil 17, Relay R3 coil 18, Relay R4 coil 19, Relay R5 coil 20 and Relay R9 coil
With 21.

On the other hand, the AC circuit 13 includes
The normally closed contact 22 of the relay R2 (hereinafter, the normally closed contact is referred to as “normally closed contact”) 22 is connected to the coil 23 of the relay R6, and the normally open contact of the relay R3 (hereinafter, normally closed contact is referred to as “normally closed contact”). 24) and normally closed contact 25 of relay R9
Is connected to the coil 26 of the relay R7.
The normally open contact 27 of the relay R1, the normally open contact 28 of the relay R1, the normally open contact 29 of the relay R3, and the coil 30 of the relay R8 are connected.

Further, a relay is connected to the normally open contact 28 of the relay R1.
Normally open contacts 31 for self-holding of R8 are connected in parallel,
A circuit drawn from between the normally open contact 27 of the relay R5 and the normally open contact 28 of the relay R1 has an electric motor for starting or stopping the electric motor for driving the construction machine via the normally open contact 32 of the relay R8. The motor start / stop circuit 33 is connected.

In the DC circuit 15, electric components are connected to the AC / DC converter 14 via a normally open contact 34 of a relay R7.
35, and a start / stop switch 39 is connected via a diode 36, a normally open contact 37 of the relay R6, and a normally open contact 38 of the relay R5.

A battery as a DC power supply is connected between the normally open contact 37 of the relay R6 and the normally open contact 38 of the relay R5.
41 and an alternator 42 as a generator for charging are connected.

The alternator 42 is mounted on the engine,
Although it is an AC generator driven by an engine, it is a charging generator that has a built-in rectifier for converting AC to DC and outputs a DC output to the battery 41.

Here, a series of circuits from the alternator 42 to the + side of the battery 41 comprises an engine driving charging circuit 61 for charging the battery 41 with a DC power supplied from the alternator 42 driven by the engine when the engine is driven.
Is formed.

On the other hand, from the AC / DC converter 14, through the diode 36 and the normally open contact 37 of the relay R6, the positive
A series of circuits reaching the side form an electric motor driving charging circuit 62 that converts the AC power of the electric motor into a DC power when the electric motor is driven and charges the battery 41.

Further, the normally open contact 34 of the relay R7 and the relay
The normally open contact 37 of R6 is an interlock circuit that supplies the voltage generated by the alternator 42 to the battery 41, the electric component 35, and the DC circuit 15 without applying the voltage generated by the alternator 42 to the diode 36 or the AC / DC converter 14. 63 are formed.

On the positive side of the battery 41, the normally open contact 43 of the relay R2, the normally closed contact 44 of the relay R7, and the coil 21 of the relay R9
And are connected. Further, a normally open contact 45 of the relay R9 is provided between the electric component 35 and the normally open contact 34 of the relay R7.

The start / stop switch 39 is a common key switch capable of starting or stopping each drive of the electric motor and the engine, and is a two-pole rotary switch having an off terminal C, a start terminal S and an ACC terminal R. It is also a key switch.

A start terminal S of the start / stop switch 39 includes a hydraulic lock switch 46 for fixing a hydraulic actuator such as a construction machine on a hydraulic circuit, a normally closed contact 47 of a relay R2, and a coil 16 of a relay R1. Further, an engine start circuit 49 is connected to a circuit drawn from between the hydraulic lock switch 46 and the normally closed contact 47 of the relay R2 via a normally open contact 48 of the relay R2.

On the other hand, the normally open contact 51 of the relay R4, the normally closed contact 52 of the relay R8, and the coil 17 of the relay R2 are connected to the ACC terminal R of the start / stop switch 39. The normally open contact 53 for self-holding of the relay R2 is connected in parallel to the normally open contact 51 of the relay R2, and the normally closed contact of the relay R8 is connected.
In the circuit drawn from between 52 and coil 17 of relay R2,
The engine stop circuit 54 is connected.

Further, the normally closed contact 55 of the relay R2 and the coil 18 of the relay R3 are connected to the ACC terminal R of the start / stop switch 39, and a normal switch for switching between an AC power supply and a DC power supply. Power switch 56, an open manual contact
And the coil 19 of the relay R4 are connected.

The normally open contact 37 of the relay R6 and the relay
An emergency stop switch 58, which is a normally closed type manual contact, and a coil 20 of the relay R5 are connected to a circuit 57 drawn out from between the normally open contact 38 of R5 and the circuit 57.

As described above, on the load side of the start / stop switch 39, the start / stop circuit for starting or stopping both the electric motor and the engine is arranged.
An emergency stop switch 58 is arranged on the power supply side of the stop switch 39.

Next, the operation (A) of the illustrated embodiment will be described.
(B) and (C) will be described.

(A) First, a method for charging the battery 41 at each drive, regardless of whether the construction machine is driven by an electric motor or an engine, will be described.

When the electric motor is driven, or when the circuit breaker 12 is in the on state without driving the electric motor, the relay
The coil 23 of R6 is excited, the normally open contact 37 of the relay R6 is closed, the coil 20 of the relay R5 is excited, and the normally open contact 38 of the relay R5 is closed, so that the AC / DC converter 14 converts AC to DC. The applied DC voltage (approximately 27 V) is applied to the battery 41 and the start / stop switch 39.

For this reason, if the voltage of the battery 41 is lower than the DC voltage (about 27 V) after the AC / DC conversion,
The battery 41 is charged by the potential difference.

On the other hand, when the engine is driven, when the power switch 56 is pressed, the coil 19 of the relay R4 is excited,
The normally open contact 51 of R4 closes, the coil 17 of the relay R2 is excited, the self-holding action of the normally open contact 53 of the relay R2 works, and the normally open contact 43 of the relay R2 closes and the coil 21 of the relay R9 closes.
Is excited, and the normally open contact 45 of the relay R9 is closed.

At this time, the normally closed contact 22 of the relay R2 is opened, so that the coil 23 of the relay R6 is de-energized.
Since the normally closed contact 55 of R2 is opened, the coil 18 of the relay R3 is also deenergized, the normally open contact 24 of the relay R3 is opened, and the coil 26 of the relay R7 is deenergized.
Opens.

That is, when the engine is driven, the relay R4,
R2 and R9 are in the excitation state (hereinafter, this excitation state is referred to as “ON state”)
), And the relays R6, R3, and R7 are in the de-energized state (hereinafter, this de-energized state is referred to as the "off state"), so that an interlock circuit is formed, and the generated voltage from the alternator 42 The voltage is not applied to the converter 14, but is supplied to the battery 41 and charged.

As described above, in a construction machine that can be driven by either the electric motor or the engine, the battery 41 can be charged both when the electric motor is driven and when the engine is driven.

(B) Next, with reference to FIGS. 2 to 4, the operation of the start / stop circuit that can start and stop each drive of the electric motor and the engine with the common start / stop switch 39 will be described. . In FIGS. 2 to 4, the excited state (ON state) of each relay R1, R2, R3, R4, R5, R6, R7, R8, and R9 is shown by a black circle, and the excited release state (OFF state) is a white circle. Indicated by

First, regardless of whether the electric motor or the engine is driven, the hydraulic operation of the construction machine is fixed by closing the hydraulic lock switch 46.

FIG. 2 shows a case in which the electric motor drives a construction machine with the electric motor.

(I) The AC power supply 11 is converted into a DC power supply by the AC / DC converter 14 and supplied to the start / stop switch 39.

As described above, the relays R6 and R5 are in the ON state, and when the start / stop switch 39 is switched to the ACC position, the relays R3 and R7 are in the ON state, and the electric component 35 is connected.

(Ii) When the start / stop switch 39 is switched to the start position, the relays R1 and R8 are turned on, power is supplied to the electric motor start / stop circuit 33, and the electric motor starts.

(Iii) When the start / stop switch 39 is switched to the off position, the relays R3 and R8 are turned off, and the electric motor stops.

FIG. 3 shows a case where the engine is driven and the AC power supply 11 is connected.

(I) The AC power supply 11 is converted into a DC power supply by an AC / DC converter 14, and DC power is supplied to a start / stop switch 39 via relays R6 and R5 in an ON state. When 39 is set to the ACC position, the relays R3 and R7 are turned on.

(Ii) When the power switch 56 is pressed to drive the engine, the relays R4 and R2 are turned on.
Relays R3, R6, and R7 are turned off, and power is
At the same time, the relay R9 is turned on, and the electric component 35 is connected to the battery 41.

(Iii) When the start / stop switch 39 is switched to the start position, DC power is supplied from the battery 41 to the engine start circuit 49, and the engine is started. When the start / stop switch 39 is switched to an off position (not shown), the power to the engine stop circuit 54 is turned off, and the engine stops.

FIG. 4 shows a case where the engine is driven and no AC power is applied.

(I) When the relay R5 connected to the battery 41 via the emergency stop switch 58 is turned on, the battery 41
Thus, DC power is supplied to the start / stop switch 39. When this start / stop switch 39 is set to the ACC position, the relay
R3 is turned on.

(Ii) When the power switch 56 is pressed to drive the engine, the relays R4 and R2 are turned on,
Relay R3 is turned off, and relay R9 is turned on.

(Iii) When the start / stop switch 39 is switched to the start position, DC power is supplied from the battery 41 to the engine start circuit 49, and the engine is started. When the start / stop switch 39 is switched to an off position (not shown), the power to the engine stop circuit 54 is turned off, and the engine stops.

As described above, only when the engine is driven, the start-up wait state is set by the power switch 56. However, the electric motor drive and the engine drive can be started or stopped by the start / stop switch 39 which is a common key switch.

Also, as shown in FIGS. 1 to 4, a hydraulic lock switch 46 is provided at the start position of the start / stop switch 39, so that when the hydraulic lock switch 46 is open, the lock is released. Since the relay R1 is off and the relay R8 cannot be excited at first, power is not supplied to the electric motor start / stop circuit 33, and power is not supplied to the engine start circuit 49, so that the electric motor and the engine are not supplied. Both drives cannot be started.

(C) Next, a description will be given of the operation of urgently stopping the drive of the electric motor and the engine both when the engine is driven.

When the electric motor is driven, the AC power supply 11
The DC converter 14 converts the DC power into DC power, and supplies the DC power to a start / stop switch 39. When the engine is driven, the DC power is supplied from a battery 41 to the start / stop switch 39. At this time, DC power is also supplied to the emergency stop switch 58 at all times.

When the emergency stop switch 58 on the power supply side of the start / stop switch 39 is pressed and opened in an emergency, the coil 20 of the relay R5 is de-energized.
Normally open contact 27 of the DC circuit 15 and normally open contact 38 of the relay R5 of the DC circuit 15.
Open together to shut off the power to the electric motor start / stop circuit 33, and also shut off the power to the start / stop switch 39 at the same time, so that both the electric motor and the engine can be stopped. Operation can be stopped.

[0058]

According to the first aspect of the present invention, the battery can be charged not only when the engine is driven but also when the electric motor is driven by the engine driving charging circuit and the electric motor driving charging circuit. It is possible to prevent battery discharge when continued.

According to the second aspect of the present invention, the interlock circuit can prevent an abnormal state in which DC from the generator is supplied to the AC / DC converter when the battery is charged when the engine is driven.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of a relay circuit including a battery charging circuit according to the present invention.

FIG. 2 is an electric circuit diagram showing an operation of the relay circuit when the electric motor is driven.

FIG. 3 is an electric circuit diagram showing an operation of the relay circuit when the engine is driven and an AC power supply is connected in the relay circuit;

FIG. 4 is an electric circuit diagram showing an operation of the relay circuit when the engine is driven and no AC power is applied in the relay circuit.

[Explanation of symbols]

 11 AC power supply 14 AC / DC converter 41 Battery 42 Alternator as generator 61 Charging circuit when driving the engine 62 Charging circuit when driving the electric motor 63 Interlock circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60L 1/00-15/42 E02F 9/20 H01M 10/44

Claims (2)

(57) [Claims] An electric motor driven by an AC power supply ,
And in either drivable machine engine is started by the battery, engine and generator for outputting DC driven by the engine when driving, the engine drive-time charging circuit for charging the battery by a DC supplied from the generator When the battery charging circuit, characterized in that the alternating current from ac power supply when the electric motor drive is converted into direct current comprises an electric motor drive-time charging circuit for charging the battery. 2. An AC / DC converter for converting AC to DC, and an interlock circuit for supplying DC from a generator to a battery without supplying the AC / DC converter when the engine is driven. The battery charging circuit according to claim 1, wherein: