JP2573885B2 - Headlamp cleaner control circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a headlamp cleaner control circuit for cleaning a headlamp by ejecting a cleaner liquid stored in a cleaner tank from a nozzle.

[Conventional technology]

2. Description of the Related Art In recent years, a headlamp cleaner has been employed in a vehicle to clean the headlamp. FIG. 9 shows a schematic configuration of the cleaner motor 3 via the control unit 2 in accordance with the ON operation of the cleaner switch 1 in the ON state of the ignition switch.
Is turned on, and the cleaner liquid stored in the cleaner tank 4 is ejected from the nozzle 5 to wash the headlamp 6 as shown in FIG.

FIG. 11 shows a headlamp cleaner control circuit built in the control unit 2 and includes PNP transistors Q1 and Q2.
, An NPN transistor Q3, diodes D1 to D5, a relay Ry with a normally open contact ry, capacitors C1 and C2, and a resistor R.
1 to R7. Note that in FIG.
Is an ignition switch, and 9 is a vehicle-mounted power supply.

 Next, the operation of the control circuit will be described.

When the ignition switch 8 is on and the cleaner switch 1 is off, the positive polarity of the vehicle-mounted power supply 9-the ignition switch 8-the resistor R7-the resistor R6-the capacitor C2-the diode D5-the capacitor C1 (resistance R4)-
Current flows through the diode D1-ground path, and the capacitor
C2 is charged. At the same time, a current flows through the path of the positive polarity of the vehicle-mounted power supply 9, the ignition switch 8, the resistor R5, the diode D5, the base-emitter of the transistor Q3, the diode D1, and the ground, and the transistor Q3 is turned on. When the transistor Q3 is turned on, the transistor Q2 is turned on, and the potential at the connection point A between the base of the transistor Q1 and the collector of the transistor Q2 is changed to the power supply voltage E
(+12) volts. For this reason, the transistor Q1 maintains the off state, no current flows to the coil CL of the relay Ry, and the normally open contact ry maintains the open state. Not done.
That is, the cleaner motor 3 maintains the inoperative state.

On the other hand, when the ignition switch 8 is on and the cleaner switch 1 is turned on, the potential of the connection point B between the capacitor C2 and the resistor R5 drops sharply, and at the same time, the discharge from the capacitor C2 starts. You. When the potential at the connection point B drops sharply, a reverse bias is applied and the transistor Q3 is turned off, and accordingly, the transistor Q2 is also turned off. As a result, the potential of the connection point A becomes the ground level, the transistor Q1 turns on, a current flows through the coil CL of the relay Ry, and the normally open contact ry is closed. Is supplied from the power supply. That is, the cleaner motor 3 is operated to inject the cleaner liquid.

On the other hand, the potential at the connection point B gradually increases due to the discharge from the capacitor C2, and when the voltage level reaches a predetermined value, that is, when a predetermined timer time has elapsed, the transistor Q3 is turned on. And the accompanying transistor
When Q2 turns on, transistor Q1 turns off and the relay
The current of Ry to the coil CL is cut off, the normally open contact ry is opened, and the operation of the cleaner motor 3 stops.

The headlamp cleaner control circuit is constructed on a printed circuit board 2-11 as a printed base assembly 2-1 on which predetermined circuit components are mounted, as shown in FIG. Is housed in the case 2-2 to form the control unit 2. FIG. 13 shows a state in which the print base assembly 2-1 is housed. The print base assembly 2-1 is cold caulked to the caulking portions 2-21 and 2-22 to the case 2-2, and the O-ring 2-3 is attached. The cover 2-4 is secured to the case 2 by tapping screws 2-5.
-2.

[Problems to be solved by the invention]

However, according to such a conventional headlamp cleaner control circuit, since the cleaner motor 3 is always connected to the positive polarity side of the vehicle-mounted power supply 9, that is, because the contact capacity of the ignition switch 8 is small, the cleaner motor 3 Since +12 volts is always applied, there is a problem that electric corrosion is easily caused by water, humidity and the like.

In order to solve the above-mentioned problem, the applicant of the present application has disclosed in Japanese Patent Application No. 2-47354, "One end of the cleaner motor is grounded, and the other end of the cleaner motor is connected to the positive side of the vehicle power supply. Connect the normally open contact of the relay between
The relay is driven in accordance with the ON operation of the cleaner switch 1 in the ON state of the ignition switch, and the normally open contact is closed for a predetermined timer time. "

However, in such a headlamp cleaner control circuit, since a relay is used, the following problem occurs, and integration with a cleaner motor is difficult.

Electric corrosion due to moisture, humidity, and the like easily occurs in the normally open contact, and the waterproof structure becomes complicated.

Weak to vibration.

Susceptible to magnetism.

[Means for solving the problem]

The present invention has been proposed in order to solve such a problem, and has a source electrode connected to the other end of a cleaner motor having one end grounded, and a drain electrode connected to the positive polarity side of the vehicle-mounted power supply. A charging means connected between the channel MOSFET, the source electrode of the FET and the positive side of the vehicle power supply via an ignition switch, for storing electric charge in accordance with the operation of turning on the ignition switch, and a cleaner in an on state of the ignition switch; The timer operation is started in accordance with the ON operation of the switch, the gate electrode of the FET is set at a high level to turn on the source electrode and the drain electrode, and charging is performed for a predetermined timer time until the timer operation is completed. The voltage applied to the gate electrode is applied to the gate electrode to maintain the gate electrode at a higher level than the source electrode. It is obtained by a means.

[Action]

Therefore, according to the present invention, one end of the cleaner motor is always grounded. That is, the connection of the other end of the cleaner motor to the positive polarity side of the vehicle
It is always disconnected via the source and drain electrodes of the ET.

Further, according to the present invention, since the N-channel MOSFET is used, electric corrosion due to moisture, humidity, and the like hardly occurs, it is strong against vibration, hardly affected by magnetism, and can be integrated with the cleaner motor. Hereinafter, a headlamp cleaner control circuit according to the present invention will be described in detail.

FIG. 1 is a circuit diagram showing one embodiment of the headlamp cleaner control circuit. 11, the same reference numerals as those in FIG. 11 denote the same components, and a description thereof will be omitted.

The headlamp cleaner control circuit 10 ₁ includes an interface section 10-1, a timer unit 10-2, a power-on reset unit 10-3, and a drive unit 10-4 Prefecture. The interface unit 10-1 includes capacitors C1 and C2,
Diode D1, NPN transistor Tr1, and resistors R1 to R4
It is composed of Timer section 10-2 is a capacitor
C3, C4, diode D2, NPN transistor Tr2, PNP transistor Tr3, and resistors R5 to R8. The power-on reset unit 10-3 includes a capacitor C5, a diode D3, an NPN transistor Tr4, and resistors R9 and R10. The driving unit 10-4 includes a capacitor C6, a diode D4, an N-channel MOSFET (insulated gate field effect transistor), a _TFET , and resistors R11 and R12.

In the headlamp cleaner control circuit 10 _1, in the drive unit 10-4, and connects the source electrode S of the T _FET at the other end of the cleaner motor 3 whose one end is grounded, onboard power supply 9
Is connected to the drain electrode D of the ET _FET . Then, it is assumed that connects a series connection circuitry through the ignition switch 8 and a diode D4 and a capacitor C6 between the source electrode S of the positive polarity side and the T _FET in-vehicle power supply 9, the resistance of the gate electrode G of T _FET It shall be grounded through the path of R12-R11. The timer unit 10-2
, The emitter of the transistor Tr3 is connected to the driving unit 10−
4, and the collector of the transistor Tr3 is connected to the node between the resistor R12 and the resistor R11 in the driver 10-4. Then, the base of the transistor Tr3 is connected to the connection point of the resistors R7 and R8, the other end of the resistor R7 is connected to the emitter of the transistor Tr3, and the resistor R8
Is grounded via a capacitor C4.

Next, the operation of the headlamp cleaner control circuit 10 _1.

When the ignition switch 8 is on and the cleaner switch 1 is off, the vehicle power supply 9-the ignition switch 8-the diode D4-the capacitor C6-
Current flows through the path of the cleaner motor 3, and the capacitor C6 is charged. That is, the source electrode S of the T _FET is +12
After soared bolts (t ₁ point shown in FIG. 7 (c)), immediately return to the ground level. In this case, T _FET has its Gut electrode G is a ground level, since not a higher level than the source electrode S, is kept off. Therefore, no current is supplied from the vehicle-mounted power supply 9 to the cleaner motor 3, and the cleaner motor 3 maintains an inoperative state.

When the ignition switch 8 is on and the cleaner switch 1 is off,
-Since the current flows through the route of -ignition switch 8-resistor R1-resistor R2-capacitor C2 (resistance R3), the transistor
Tr1 remains on. Also, a vehicle power supply 9-an ignition switch 8-a diode D4-a resistor R7-a resistor R8-
Current flows through the path of the capacitor C4, and the capacitor C4 is charged. Further, a current flows through a path of the vehicle-mounted power supply 9, the ignition switch 8, the capacitor C5, the resistor R9, and the resistor R10, and the capacitor C5 is charged. In the present embodiment, the time constant of the charging path to the capacitor C5 is
4 is set to be larger than the time constant of the charging path to C4, so that even if transistor Tr3 is turned on during the charging period of capacitor C4, transistor
4 keeps the ON state, and keeps the gate electrode G at the ground level. For this reason, the T _FET maintains the off state, and no malfunction occurs.

On the other hand, when the ignition switch 8 is on and the cleaner switch 1 is turned on, the transistor Tr1 is turned off and the transistor Tr2 is turned on for a short time (one shot time). This allows
The charge accumulated in the capacitor C4 is the resistance of the resistor R6 and the transistor Tr2.
And discharge path of the transistor Tr3 is turned on by a reduction in its base potential (t ₂ points shown in FIG. 7 (a)). That is, the timer operation in the timer section 10-2 starts, and a current flows through the path of the vehicle-mounted power supply 9, the ignition switch 8, the diode D4, the transistor Tr3, and the resistor R11. Thus, the diode D4 and the connection point voltage (+12 volts) is applied to the gate electrode G of T _FET (FIG. 7 (b) to show t ₂ points) of the E of the capacitor C6, the gate electrode G is the source electrode S Higher level than Therefore, T _FET is turned on, the source electrode S is a +12 volts (Figure 7 (c) to indicate t ₂ points), the current supply to the cleaner motor 3 is started. As a result, the cleaner motor 3 operates, and the injection of the cleaner liquid is started.

On the other hand, the source electrode S of the T _FET is +12 volts, the potential at the connection point E is soared +24 volts (Figure 7 (d) to indicate t ₂ points), the gate electrode G of T _FET receives this potential also increases rapidly (t ₂ points shown in FIG. 7 (b)). Then, due to the discharge of the accumulated charge from the capacitor C6 via the transistor Tr3, the potential of the connection point E gradually decreases, and accordingly, the potential of the gate electrode G gradually decreases. During this time, when the transistor Tr2 is turned off, the capacitor C4 resumes charging. This increases the base potential of the transistor Tr3 gradually, eventually turns off the transistor Tr3 (FIG. 7 (a) to indicate t ₃ points). That is, the timer operation in the timer section 10-2 ends, and the gate electrode G is forcibly returned to the ground level (t shown in FIG. 7 (b)).
₃ points). The beetle to ground level of the gate electrode G, T _FET is turned off, returned source electrode S is the ground level (the 7 t ₃ points shown in Figure (c)), the potential at the connection point E +12 drops to the bolt (point t ₃ when shown in FIG. 7 (d)).

That is, the charging voltage of the capacitor C6 is applied only for the timer time T during which the transistor Tr3 is ON, that is, for the timer time T until the timer operation in the timer section 10-2 ends, and the gate electrode G to hold than the electrode S to a high level, during this period T _FET is kept on, the current supply to the cleaner motor 3 is performed, the injection of the cleaner liquid is continued. Then, when the timer time T elapses, the T _FET is turned off, the current to the cleaner motor 3 is cut off, and the operation of the cleaner motor 3 stops.

FIG. 2 shows a second embodiment of the headlamp cleaner control circuit according to the present invention. In this headlamp cleaner control circuit 10 _2, using the comparator IC2 to the timer unit 10-21. The power-on reset unit 10
−31 is composed of a diode D3, a capacitor C5, and resistors R8 and R9.The potential of the connection point between the capacitor C5 and the resistor R9 is applied to the inverting input terminal of the comparator IC2, and the capacitor C4 and the resistor R7 are applied to the non-inverting input terminal of the comparator 1C2. And a potential at a connection point between the two. Then, the output of the comparator IC2 is
It is provided via a resistor R11 to the base of a transistor Tr3 disposed on the driving section 10-41 side.

Headlamp cleaner control circuit configured as above
10 In the _2, an ignition switch 8 is turned on, when turned on the cleaner switch 1, the transistor Tr2 is turned on, the accumulated charge in the capacitor C4 is discharged, suddenly donating voltage of the non-inverting input Because of the decrease, the output of the comparator IC2 becomes “L” level. As a result, the transistor Tr3 is turned on, the voltage at node E (+12 volts) is applied to the gate electrode G of T _FET,
T _FET turns on. Then, the on state of the T _FET is by charging people pressure at capacitor C6, it is maintained the gate electrode G as a higher level than the source electrode S. During this time,
When the transistor Tr2 is turned off, the capacitor C4 resumes charging and gradually increases the voltage supplied to the non-inverting input terminal of the comparator IC2. When the applied voltage to the non-inverting force terminal becomes higher than the applied voltage to the inverting input terminal, the output of the comparator IC2 is returned to "H" level,
When the transistor Tr3 is turned off, the gate electrode G of the T _FET
Is forcibly returned to the ground level. This gate electrode G
As a result, the T _FET is turned off, and the source electrode S is returned to the ground level.

Incidentally, in this headlamp cleaner control circuit 10 _2, the time constant of the charging path of the capacitor C5 capacitor
It is set larger than the time constant of the charging path to C4.
For this reason, when the ignition switch 8 is turned on, the voltage setting at the inverting input terminal of the comparator IC2 lags behind the voltage setting at the non-inverting input terminal, and the supply voltage to the inverting input terminal changes to the non-inverting input terminal. , And no malfunction occurs. Further, in this headlamp cleaner control circuit 10 _2, the time constant of the discharge path from the capacitor C5 capacitor
It is set smaller than the time constant of the discharge path from C4. For this reason, when the ignition switch 8 is turned off, the disappearance of the set voltage to the inverting input terminal of the comparator IC2 becomes faster than the disappearance of the set voltage to the non-inverting input terminal, and the supply voltage to the inverting input terminal becomes non-inverting. The voltage does not become higher than the applied voltage to the inverting input terminal, and no malfunction occurs.

FIG. 3 shows a third embodiment of the headlamp cleaner control circuit according to the present invention. In the headlamp cleaner control circuit 10 ₃ with respect to headlamp cleaner control circuit 10 ₂ described above, it has a connection to the non-inverting input and the inverting input terminal of the comparator IC2 at the timer section 10-21 'opposite . Further, the configuration of the driving unit 10-42 is different. That is, in the driving section 10-42, the transistor Tr
The output of the comparator IC2 is connected to the connection point between the diode D4 and the capacitor C6 via the resistor R10, omitting the circuit 3 and the circuit associated therewith. In the headlamp cleaner control circuit 10 ₃ thus configured, a ignition switch 8 is turned on, when turned on the cleaner switch 1, the comparator IC2
Becomes "H" level. As a result, the voltage of the "H" level is applied to the gate electrode G of T _FET, T _FET is turned on. When the T _FET is turned on and its source electrode S reaches +12 volts, the potential at the connection point E rises sharply to +24 volts. This also received soaring potential of the gate electrode G of T _FET, because the gate electrode G is maintained at a higher level than the source electrode S, T _FET lasts the ON state. At this time, the accumulated charge in the capacitor C6 is hardly discharged, that is, the discharge is slightly discharged by the wetting current, but the capacitor C6 basically keeps the charged state. The gate electrode G by adding the charging people pressure at capacitor C6 maintaining target high-level state, to sustain the ON state of the T _FET. By adopting such a method, a small-capacity capacitor can be used as the capacitor C6, and the cost can be reduced.

FIG. 4 shows a fourth embodiment of the headlamp cleaner control circuit according to the present invention. In the headlamp cleaner control circuit 10 ₄ with respect to the headlamp cleaner control circuit 10 ₃ described above, is different from configuration of the interface unit 10-11. That is, the interface unit 10-11
, The transistor Tr1 is omitted, and a comparator IC1 is used instead. Many IC packages include two operational amplifiers. By using the operational amplifiers as the comparators IC1 and IC2, the IC package can be effectively used.

FIG. 5 shows a fifth embodiment of the headlamp cleaner control circuit according to the present invention. In this headlamp cleaner control circuit _105, with respect to the headlamp cleaner control circuit 10 ₃ described above, it is different from configuration of the interface unit 10-12. That is, the interface unit 10-12
Is configured to use a PNP transistor as the transistor Tr1. By using a PNP transistor as the transistor Tr1, a malfunction when the ignition switch 8 is turned off can be prevented.
That is, in the headlamp cleaner control circuit 10 _3, when the ignition switch 8 is turned off, the stored charge in the capacitors C4 and C5 is discharged and the transistor Tr2 is turned on. Therefore, the output of the comparator IC2 becomes “H” level, the T _FET is turned on, and current is supplied to the cleaner motor 3 for a short time. In contrast, in the headlamp cleaner control circuit _105, when the ignition switch 8 OFF, the transistor Tr1 is kept off, not the transistor Tr2 is turned on and the supply of current to the cleaner motor 3 Is blocked.

FIG. 6 shows a headlamp cleaner control circuit according to a sixth embodiment of the present invention. In this headlamp cleaner control circuit _106, compared headlamp cleaner control circuit ₁₀₅ described above, it is different from configuration of the timer section 10-22. That is, in the timer section 10-22, the transistor Tr2 is omitted, and the comparator IC1 is used instead.

As described above in detail with reference to the first to sixth embodiments, according to the headlamp cleaner control circuit 10 according to the present embodiment, one end of the cleaner motor 3 is always grounded, and the on-board power supply at the other end of the cleaner motor 3 is connected. 9 is connected to the positive side
Since the disconnected at all times through the source electrode S and the drain electrode D of T _FET, water, it becomes unlikely to occur electrolytic corrosion by humidity. Also, N-channel MOSFET · T _FET is water, corrosion hardly occurs collector due to humidity or the like, vibration resistance, hardly influences also received magnetic, low on-resistance, since having the advantage of small like fever, headlamp cleaner The control circuit and the cleaner motor 3 can be integrated with a simple waterproof structure to achieve a reduction in size. FIG. 8 is a side sectional view illustrating an integrated structure of the head amplifier cleaner control circuit 10 and the cleaner motor 3, where 3-1 is an amateur, 3-2 is a stator, 3-31 and 3- 32 is a bearing, 3-4 is a commutator, and 3-5 is a motor case. In this integrated structure, a headlamp cleaner control circuit 10 is constructed on a printed circuit board 11 to form a print base assembly 12, and the print base assembly 12 is disposed on the bottom of the motor case 3-5 to provide a simple waterproof structure. Has been given. Then, the headlamp cleaner control circuit 10
Power supply to the female hard connector 13 to the male hard connector 14
This is performed by fitting.

In the headlamp cleaner control circuit 10, N
It is conceivable to use a P-channel MOSFET instead of the channel MOSFET. However, the P-channel MOSFET has a large on-resistance, is not suitable for driving a large-current motor, and is expensive. In this embodiment, the N-channel MOSFET
In order to use the device as if it were a P-channel MOSFET, various ideas have been devised.

It is also conceivable to use a PNP transistor instead of the N-channel MOSFET. However, it is necessary to increase the base current, and the amount of heat generated is large.

〔The invention's effect〕

As is clear from the above description, according to the headlamp cleaner control circuit of the present invention, one end of the cleaner motor is always grounded, that is, the connection of the other end of the cleaner motor to the positive side of the vehicle power supply is N. The channel MOSFET is always separated via the source electrode and the drain electrode of the channel MOSFET, and is less likely to cause electrolytic corrosion due to water, humidity, and the like.

Further, according to the present invention, since the N-channel MOSFET is used, electric corrosion due to moisture, humidity, etc. hardly occurs, it is resistant to vibration, it is hard to be affected by magnetism, and only a simple waterproof structure is applied. And integration with the cleaner motor becomes possible.

[Brief description of the drawings]

1 to 6 are circuit diagrams showing first to sixth embodiments of a headlamp cleaner control circuit according to the present invention, and FIG. 7 explains the operation of the headlamp cleaner control circuit shown in FIG. FIG. 8 is a side sectional view illustrating an integrated structure of a headlamp cleaner control circuit and a cleaner motor, FIG. 9 is a schematic configuration diagram of a headlamp cleaner in a vehicle, and FIG. FIG. 11 is a perspective view showing a cleaning state of a headlamp by a cleaner, FIG. 11 is a circuit configuration diagram showing a conventional headlamp cleaner control circuit, and FIG. 12 is a print base assembly having the headlamp cleaner control circuit and the print base assembly. FIG. 13 is a side sectional view showing a state in which the print base assembly is housed. 1 ... cleaner switch, 3 ... cleaner motor, 8 ...
... ignition switch, 9 ...... vehicle power supply, 10 ₁ to 10 ₆
...... Head lamp cleaner control circuit, 10-1, 10-11, 10
−12 …… Interface part, 10−2, 10−21, 10−21 ′,
10-22 Timer section, 10-3, 10-31 Power-on reset section, 10-4, 10-41, 10-42 Drive section, T _FET
N-channel MOSFET, C6 ... Capacitor.

Claims (1)

(57) [Claims] 1. An N-channel MOSFET having one end connected to the other end of a grounded cleaner motor and the drain electrode connected to the positive side of a vehicle-mounted power supply; a source electrode of the FET; A charging means connected through an ignition switch to the positive polarity side of the charging switch for storing electric charge in accordance with the operation of turning on the ignition switch; and starting the timer operation in accordance with the operation of turning on the cleaner switch in the on state of the ignition switch. Then, the gate electrode of the FET is set to a high level to turn on the source electrode and the drain electrode, and the charging pressure in the charging unit is reduced for a predetermined timer time until the timer operation is completed. Timer means for holding the gate electrode at a higher level than the source electrode, in addition to the gate electrode. Ete become head lamp cleaner control circuit.