JP3135961B2 - Wiper drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiper driving device for wiping a wiping surface of an automobile windshield glass or the like with a wiper blade.

[0002]

2. Description of the Related Art A wiper driving device for wiping a wiping surface of a windshield glass or the like of an automobile with a wiper blade is disclosed in Japanese Utility Model Publication No. 56-48941.

[0003] In the wiper driving device described in the above-mentioned publication, the coil of the relay is turned on in synchronization with the turning on of the switching transistor. When the relay coil is turned on, the relay contact connected to the brush terminal of the wiper wiper motor is switched to operate to form an energizing path for the wiper motor. On the other hand, the wiping operation was performed in a round trip.

[0004]

However, in the above-mentioned conventional wiper driving device, since the energizing path of the wiper motor is formed by the relay contacts of the relay, it is difficult to say that the response performance is excellent. There is a problem that an operation sound may be generated, and it cannot be said that an arc is not generated between the relay contacts. In addition, since it is weak against impacts such as dropping, there is a problem in terms of durability, and since it is a combination of a coil and a relay contact, it is difficult to reduce the external dimensions, and chopping control with a low voltage level There was a problem that was not suitable for.

[0005]

The problem to be solved by the present invention is that, when the energizing path of the wiper motor is formed by a relay, the response performance is inferior and an operating noise is generated, an arc is generated and the durability is inferior. Another disadvantage is that it is not suitable for chopping control and the outer shape becomes large.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to form a contactless output stage to provide excellent response performance, no operation noise, no arc generation, excellent durability, chopping control, and a small number of output stages. It is an object of the present invention to provide a wiper driving device that can have a compact outer shape by forming an output stage with a semiconductor element.

[0007]

Configuration of the Invention

[0008]

The wiper driving device according to the present invention has switch means for setting an arbitrarily selected mode, and an output terminal for outputting a signal corresponding to the mode set by the switch means. A wiper driving device comprising: a mode control unit; and a driving unit that operates in response to an output signal from the mode control unit to control power supply to the wiper motor. The wiper motor includes a first terminal connected to a power supply, A second terminal connected to the driving means, wherein the driving means has an input terminal connected to the mode control means, a power supply terminal connected to the second terminal of the wiper motor, and an emitter connected to the power supply. P-channel type first transistor having a gate connected to the collector of the first transistor and a source connected to the power supply. And T, a drain connected to a first terminal of a wiper motor, to the drain of the first FET,
An N-channel type second FET whose source is grounded,
One is the collector of the first transistor and the other is the first FET
A passive resistor connected to the gate of the second FET and the other connected to the gate of the second FET; a collector connected to the other of the passive resistors and the gate of the second FET; an emitter grounded;
NPN whose base is connected to the power supply via a bias resistor
A third transistor of NPN type having a base connected to the input terminal, a collector connected to the base of the first transistor and connected to the base of the second transistor, and an emitter grounded. And a transistor.

[0009]

In the wiper driving device according to the present invention, the passive resistor has a function for driving the second FET together with the PNP transistor, and the PNP transistor is used for not driving the first FET. Has functions. Further, the passive resistor has a function of gradually driving the second FET from a non-driven state. Therefore, the control of the wiper wiper motor can be performed as a simple circuit module having no contact, and the first and second FETs are not simultaneously turned on by the passive resistance.

[0010]

1 and 2 show an embodiment of a wiper driving apparatus according to the present invention.

The illustrated wiper driving device 1 is mainly composed of switch means 2, mode control means 3, and driving means 4.

The switch means 2 is provided with a switch for setting each mode of wiper stop, wiper automatic operation, wiper intermittent operation, and wiper low speed (high speed) operation. When the switch is operated, a mode command set via the signal line 5 connected to the output terminal 2a is transferred to the input terminal 3a provided in the mode control means 3.

The mode control means 3 includes the input terminal 3
a, a ground terminal 3b, a fixed position stop signal input terminal 3c, an output terminal 3d, and a power supply terminal 3e. The signal input from the input terminal 3a and the fixed position stop signal input terminal 3c is processed and then output. A processing circuit for outputting a driving means operating signal from the terminal 3d is built in. This driving means operating signal is a trigger signal for turning on a third transistor Tr3 provided in the driving means 4 described later.

When a command for the automatic wiper operation mode is input from the switch means 2, the mode control means 3 outputs an output terminal when a raindrop detection signal from a raindrop detection means (not shown) such as a raindrop sensor is received. The driving signal is output from 3d. Further, when the command for the intermittent wiper operation mode is input from the switch means 2, the mode control means 3 outputs via the pause time arbitrarily set by the processing circuit (the pause time can be changed by a manual switch). A driving means operating signal is output intermittently from the terminal 3d. When the mode control unit 3 receives a command of the wiper low speed (high speed) operation mode from the switch unit 2,
The drive means operation signal is continuously output from the output terminal 3d.

Further, when the command is interrupted while the command of each of the operation modes is being inputted, the mode control means 3 is connected to the fixed position stop signal input terminal 3c while it is connected to the ground. The drive means operating signal is continuously output from the output terminal 3d, and the output is stopped when the fixed position stop signal input terminal 3c is connected to the power supply side.

The driving means 4 includes an input terminal 4a connected to an output terminal 3d of the mode control means 3 via a signal line 6,
A ground terminal 4b and power supply terminals 4c and 4d are provided, and the first FET 10, the second FET 20,
A half-bridge circuit is composed of a transistor Tr1 as a first active element, a transistor Tr2 as a second active element, and a passive resistor R as a passive element.

The first FET 10 is of a P-channel type, the second FET 20 is of an N-channel type, the first transistor Tr1 is of a PNP type, and the second transistor Tr2 is of an NPN type.

One end of the passive resistor R is connected in series to the gate of the first FET 10 and the collector of the first transistor Tr1, and the other end of the passive resistor R is connected to the gate of the second FET 20 and the second transistor Tr2. Are connected in series to the collector. This passive resistance R is cut off the first FET 10 in synchronization with the turning on of the first transistor Tr1 when the second transistor Tr2 is turned on and the first FET 10 is turned on. The FET 20 is turned on, the second FET 20 is cut off in synchronization with the turning off of the first transistor Tr1, and the first FET
The first FET 10 is gradually turned on by a delay circuit formed by the capacitor included in the first FET 10.

The source of the first FET 10 is connected to the power supply terminal 4c on one side, and the drain of the first FET 10 is connected to the power supply terminal 4d on the other side. The source of the second FET 20 is connected to ground, and the second F
The drain of the ET is connected to the power supply terminal 4d on the other side.

The emitter of the first transistor Tr1 is connected to the source of the first FET 10, and the base of the first transistor Tr1 is connected to the collector of the third transistor Tr3 via the resistor r1. A resistor r2 is connected between the emitter and the base of the first transistor Tr1, and a base of the second transistor Tr2 is connected to a connection point on the emitter side of the resistor r2 via a resistor r3 and a resistor r4. A diode D1 is connected to a connection point between the resistors r3 and r4 and the collector of the third transistor Tr3 toward the collector.
The base of r2 is grounded via a resistor r5. Third
Of the transistor Tr3 is connected to the ground,
The base of the third transistor Tr3 is connected to ground via a resistor r6, and is connected to an input terminal 4a via a resistor r7.

The driving means 4 includes a third transistor Tr3
Is turned on, the first transistor Tr1 is turned on,
The second FET 20 is turned on via the passive resistor R to generate a potential between the power supply terminals 4c and 4d. Power supply terminals 4c and 4d of the driving means 4 are connected to first and second power supply terminals 9a and 9b provided on the wiper motor 9 via power supply lines 7 and 8, respectively. Power supply is connected. That is, the first terminal 9a is connected to the power supply,
Is connected to the driving means 4.

On the other hand, a wiper blade 11 is connected to a motor shaft 9c provided on the wiper motor 9 via a link 12, and the wiper blade 11 is connected to the motor shaft 9c.
Windshield glass W which is the wiping surface by rotation of c
G is wiped back and forth between a stop position A (lower inversion position) and an upper inversion position B. The wiper motor 9 is provided with a fixed position stop switch 9d. The fixed position stop switch 9d switches the movable contact 9e from the ground contact 9f to the power supply contact 9g every one rotation of the motor shaft 9c.

When the wiper blade 11 reaches the stop position A, the movable contact 9e is connected to the power contact 9g.
When the wiper blade 11 is not at the stop position A, the switch is switched to the ground contact 9f and is connected to the fixed position stop signal input terminal 3c of the mode control means 3.

The first and second terminals 9a, 9a,
Brush terminals 9h and 9i are connected to 9b, and one brush terminal 9h is connected to a power supply side contact 9g of a fixed position stop switch 9d.

The wiper driving device 1 having such a structure
Performs the operation shown in FIG. In the initial state (time a shown in FIG. 2) in which the mode command by the switch means 2 is the wiper stop, the driving means operation signal is not output from the output terminal 3d of the mode control means 3. Therefore, the third of the driving means 4
Transistor Tr3 is off. At this time, the power supply terminal 4c of the wiper motor of the driving means 4, the resistance r3,
The current flows through the resistors r4 and r5, and the second transistor T
r2 is on, the first F
ET10 is on.

When a driving device operation signal is output from the output terminal 3d of the mode control device 3 at time b in response to an operation mode command from the switch device 2, the third transistor Tr3 of the driving device 4 is turned on. Third transistor Tr
3 is turned on, the power supply terminal 4c of the wiper motor of the driving means 4, the emitter of the first transistor Tr1, the first
Of the transistor Tr1, the resistor r1, and the collector of the third transistor Tr3, the first transistor Tr1 is turned on. At the same time, the second transistor Tr2 is turned off via the diode D1, so that the drain potential of the first FET 10 is cut off, and the first FET 10 is turned off.

When the first transistor Tr1 turns on,
The second FET 20 turns on via the passive resistor R. Second
When the FET 20 is turned on, the potential of the power supply terminal 4d of the driving means 4 decreases, so that one brush terminal 9h of the wiper motor 9 and the other brush terminal 9i of the wiper motor 9
To rotate the motor shaft 9c. When the motor shaft 9c rotates, the wiper blade 11 wipes back and forth between the stop position A and the upper turning position B of the wiping surface WG via the link 12.

Then, the wiper blade 11 is moved to the stop position A.
When the wiper stop mode is instructed by the switch means 2 when the switch is not in the position, the mode control means 3 controls the drive means until the fixed position stop signal input terminal 3c is switched from the ground side to the power supply side by the fixed position stop switch 9. The operation signal is continuously output, and the output is turned off when the fixed position stop signal input terminal 3c is switched to the power supply side. At this time, since the movable contact 9d of the fixed position stop switch 9 is switched to the power supply side contact 9g, a closed loop is formed on one brush terminal 9h and the other brush terminal 9i of the wiper motor 9, so that the motor shaft 9c is instantaneously moved. Then, the wiper blade 11 is stopped at a predetermined stop position A.

Then, at time c, the output of the driving means operating signal is turned off, and at the same time, the passive resistor R and the first FE are turned off.
The first FET 10 is gradually turned on until the time d, and returns to the initial state by the delay circuit formed by the capacitor in T10.

In the embodiment of the wiper driving apparatus according to the present invention, the one-speed wiper motor 9 is described. However, the present invention is not limited to the one-speed wiper motor.

[0031]

As described above, according to the wiper driving device according to the present invention, the passive resistor has a function of driving the second FET together with the PNP transistor, and the PNP transistor has the following functions. It has a function of not driving the first FET. Further, the passive resistor has a function of gradually driving the second FET from a non-driven state. Therefore, the control of the wiper wiper motor can be performed as a simple circuit module having no contact, and the first and second FETs are not simultaneously turned on by the passive resistance. Therefore, compared to the wiper motor having an energizing path formed by a relay, since there is no contact point, the response performance is excellent, operation noise is eliminated, arc is not generated, durability is improved, and chopping control can be performed. In addition, since it is a module with a simple circuit, the external shape can be made extremely compact, and even if the power is turned on accidentally,
This has an excellent effect that the destruction of the second FET can be prevented.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of one embodiment of a wiper driving device according to the present invention.

FIG. 2 is a time chart for explaining an operation of the wiper driving device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiper drive device 2 Switch means 3 Mode control means 3d Output terminal 4 Drive means 4a Input terminal 4d Power supply terminal 9 Wiper motor 9a First terminal 9b Second terminal 10 First FET 20 Second FET r3 Bias resistance r4 bias resistor R passive resistor Tr1 first transistor Tr2 second transistor Tr3 third transistor

Continuation of the front page (56) References JP-A-57-25177 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 1/22

Claims (1)

(57) [Claims] A switch for setting a mode arbitrarily selected; a mode controller having an output terminal for outputting a signal corresponding to the mode set by the switch; and an output from the mode controller. A wiper driving device having a drive unit that operates in response to a signal to perform power control on the wiper motor, wherein the wiper motor has a first terminal connected to a power supply and a second terminal connected to the drive unit The driving means comprises: an input terminal connected to the mode control means; a power supply terminal connected to a second terminal of the wiper motor; and a PNP-type first terminal having an emitter connected to a power supply. A first FET of a P-channel type having a gate connected to the collector of the first transistor and a source connected to a power supply; A first terminal of the wiper motor, said first
An N-channel type second FET connected to the drain of the first FET and having a source grounded, one of which is a collector of the first transistor,
A passive resistor connected to the gate of the ET and the other connected to the gate of the second FET; a collector connected to the other of the passive resistors and the gate of the second FET; an emitter grounded; Is connected to a power supply via a bias resistor, an NPN type second transistor, a base is connected to the input terminal, and a collector is connected to the first terminal.
Connected to the base of the second transistor and the second
And a third transistor of an NPN type connected to the base of the transistor and having an emitter grounded.