JP3026657B2 - Wiper control device - 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 control device which is suitably implemented for a vehicle and drives a wiper blade at a wiping interval suitable for a rainy condition.

[0002]

2. Description of the Related Art In a typical prior art, a so-called automatic wiper control device for controlling a wiper operation based on the output of a raindrop sensor integrates the outputs of the raindrop sensor and when the integrated value exceeds a predetermined control threshold value. Is configured to start the wiping operation of the wiper blade. As a result, the wiper blade is automatically driven at the optimum wiping interval in a rainy state.

[0003]

The raindrop sensor is disposed apart from a windshield, which is a region where a rainfall condition is to be detected, such as a hood or a front grill of an automobile, and the raindrop detection range of the raindrop sensor is as described above. Extremely small compared to the area of the windshield.

[0004] Therefore, especially for extremely small-diameter raindrops such as drizzle and raindrops jumped up by a preceding vehicle, the raindrops are missed, and the wiping operation is performed later than the timing when the driver feels optimal. Will be.

In order to prevent such a problem, when the control threshold value is reduced and the raindrop detection sensitivity is increased, variations in the output pulses from the raindrop sensor due to the narrow detection range are caused by: Even though the rainfall state has not changed, the wiping interval fluctuates and becomes unstable.

It is an object of the present invention to provide a wiper control device that can drive a wiper blade at an optimum wiping interval that matches the driver's feeling.

[0007]

According to the present invention, a raindrop sensor for detecting a rainfall state, a driving means for driving a wiper blade to reciprocate on a surface to be wiped, and an output signal from the raindrop sensor are integrated. The time at which the integrated value becomes equal to or greater than a predetermined threshold value and the time at which a predetermined time elapses from the time when the integrated value becomes equal to or more than a predetermined auxiliary determination level equal to or less than the threshold value, whichever is earlier, And a control unit for driving the driving unit.

The present invention also provides a raindrop sensor for detecting a rainfall condition, a driving means for driving a wiper blade to reciprocate on a surface to be wiped, a pulse width of an output signal from the raindrop sensor, and the integrated value. The driving means at the earlier of the time when the integrated value becomes equal to or more than a predetermined threshold value and the time when a predetermined time elapses from when the integrated value becomes equal to or more than a predetermined auxiliary determination level equal to or less than the threshold value. And a control unit for driving the wiper.

Further, in the present invention, the predetermined time is set in accordance with the rate of increase of the integrated value. Furthermore, the predetermined time according to the present invention is characterized in that the predetermined time is set in accordance with the frequency of occurrence of an output signal from the raindrop sensor.

[0010]

According to the present invention, an output signal corresponding to the detected raindrop is derived from the raindrop sensor. A control device realized by a microcomputer or the like reads and integrates the output signal, or integrates the pulse width of the output signal. When the integrated value becomes equal to or greater than a predetermined threshold, a driving signal is output to a driving unit realized by a motor or the like. The driving unit drives the wiper blade to reciprocate on a surface to be wiped such as a windshield in response to the driving signal.

In connection with the threshold value, an auxiliary discrimination level equal to or less than the threshold value is set, and the control means also determines whether or not the integrated value becomes equal to or higher than the auxiliary judgment level before reaching the threshold value. After the time elapses, the wiper blade is driven. The predetermined time is determined based on the frequency of occurrence of the output pulse from the raindrop sensor and the rate of increase of the integrated value. Therefore, when the integrated value is equal to or greater than the auxiliary determination level, even if the variation or reading of raindrops due to the narrow detection range of the raindrop sensor occurs,
The integrated value increases in a pseudo manner as it is at the rate of increase up to the auxiliary determination level, and the wiper blade is driven when the threshold value is reached. This makes it possible to prevent delay in wiping timing without setting the raindrop detection sensitivity unnecessarily high.

[0012]

FIG. 1 is a block diagram showing an electrical configuration of a wiper control device 1 according to one embodiment of the present invention. This wiper control device 1 is used for a vehicle, and when an automatic wiper switch 2 is turned on, a control circuit 3 drives and controls a wiper motor 5 as a driving unit in response to an output from a raindrop sensor 4. This is a so-called automatic wiper control device that performs a wiping operation by reciprocally displacing a wiper blade that does not operate on a windshield.

The raindrop sensor 4 includes, for example, a pair of light-emitting elements and a light-receiving element, and detects a rainfall amount based on a change in a light-receiving level caused by raindrops passing through an optical path formed by these light-receiving and light-emitting elements. This is an optical raindrop sensor for detecting. The output from the raindrop sensor 4 shown in FIG. 2A is input to the control circuit 3 and shaped into a rectangular pulse by the waveform shaping circuit 11 as shown in FIG. It is input to a processing circuit 12 realized by a computer or the like. The output of the auto-wiper switch 2 is supplied to a waveform shaping circuit 13 from which noise components such as so-called chattering are removed.
Is input to

Each circuit in the control circuit 3 including the processing circuit 12 is connected to the constant voltage circuit 29 from the power supply line L2.
, Power is supplied from the battery 23. When power is supplied from the constant voltage circuit 29 and the automatic wiper switch 2 is turned on, the processing circuit 12 reduces the output pulse width W1 from the raindrop sensor 4 as shown in FIG. At time t1 when the integrated value M1 becomes equal to or greater than a predetermined threshold value RP, the wiper motor 5 is driven.

As shown in FIG. 3, an auxiliary discrimination level RA is provided in the vicinity of the threshold value RP, which is equal to or less than the threshold value RP, in relation to the threshold value RP.
The wiper motor 5 is driven at a time t3 when a predetermined time W2 has elapsed from a time t2 when the integrated value M1 becomes equal to or higher than the auxiliary determination level RA. For example, the threshold R
P is selected to be 50 msec, and the auxiliary determination level RA is 45 msec smaller than the threshold value RP by 5 msec.
Is chosen. The time W2 is selected to be, for example, 1 second. Therefore, in this case, the time W3 from the time t4 when the operation of integrating the raindrop pulse is started to the time t2 is 9 seconds.
When the value is c, as indicated by the phantom line L10 in FIG. 3, at the rate of increase of the integrated value M1 up to the time t2, when the integrated value M1 increases in a pseudo manner and becomes the threshold value RP. The wiping operation is performed.

The time W2 is measured by a counter 32 provided in the processing circuit 12. The time W2 is the rate of increase of the integrated value M1 up to the time t2,
That is, it may be determined based on M1 / W3, or may be determined based on the number of occurrences of raindrop pulses per unit time shown in FIG.

As described above, when the raindrops are continuously detected without missing, the processing circuit 12 shown in FIG.
As shown in (3), when the integrated value M1 becomes equal to or more than the threshold value RP, the wiper motor 5 is driven, and when the integration proceeds to the auxiliary determination level RA smaller than the threshold value RP,
If the integrated value M1 does not increase due to the narrow detection range of the raindrop sensor 4 or missing raindrops, the time t
It is estimated that the integrated value M1 has increased at an increase rate substantially equal to the increase rate up to 2, and anticipation control is performed at time t3 when the estimated integrated value M1 becomes equal to or larger than the threshold value RP. by this,
It is possible to reduce the influence of variation of raindrops due to the narrow detection range of the raindrop sensor 4 and reduce the influence of missing raindrops without setting the raindrop detection sensitivity unnecessarily high. The wiper motor 5 can be driven at an optimum wiping interval that matches the feeling of the user.

When the wiper motor 5 is driven at a low speed, the processing circuit 12 outputs a drive signal from the output terminal P2 to the line L3. This drive signal is applied to the base of the transistor Tr2 via the resistor R3 and the bias resistor R4. The emitter of the transistor Tr2 is grounded, and the collector is connected to the power supply line L2 via the relay coil 27 of the relay 26.

On the other hand, the relay switch 2 of the relay 26
8 has two individual contacts 28a and 28b, one of which is connected to the power line L2 and the other of which is connected to the common contact 30c of the cam switch 30 via the line L4. I have. The common contact 24c of the relay switch 24 of the relay 21 is connected to the common contact 28c of the relay switch 28,
a is connected to the low-speed power input terminal 5a of the wiper motor 5.

When the wiper motor 5 is driven continuously at high speed, the processing circuit 12 outputs drive signals to the lines L1 and L3 from the output terminals P1 and P2. The drive signal for the line L1 is input to the base of the transistor Tr1 via the resistors R1 and R2, and the drive signal for the line L3 is input to the base of the transistor Tr2 via the resistors R3 and R4.

The transistor Tr1 has an emitter grounded and a collector connected to the relay coil 22 of the relay 21.
To the power supply line L2. One individual contact 24b of the relay switch 24 of the relay 21 is
It is connected to a high-speed power input terminal 5b of the wiper motor 5.

In connection with the wiper motor 5, a cam switch 30 is provided, and the cam switch 30 is connected to the individual contact 3 when the wiper blade is in the initial position.
0a, the wiper motor 5 is started, the wiper blade starts the wiping operation, and at a point away from the initial position, the individual contact 30b is conductive, the wiper blade finishes the wiping operation, and then returns to the initial position. At the time when the contact is restored to the above state.

The individual contact 30a is grounded together with the ground terminal 5c of the wiper motor 5, and the individual contact 30b is
It is connected to the power supply line L2. Common contact 3
0c is connected to the individual contact 28a of the relay switch 28 via the line L4,
The potential 0c is detected by the processing circuit 12 from the line L5 via the signal processing circuit 31. Processing circuit 12
Determines from the detected potential of the common contact 30c whether or not the wiper blade is performing the wiping operation.

Accordingly, when driving the wiper motor 5 at a low speed, the processing circuit 12 outputs a drive signal from the output terminal P2 to the line L3. As a result, the transistor Tr2 is turned on, the relay coil 27 is excited, and the contacts 28b and 28c of the relay switch 28 are turned on.
Therefore, the battery 23 via the power line L2
Is supplied to the low-speed power input terminal 5a of the wiper motor 5 from the contacts 28b and 28c via the contacts 24c and 24a of the relay switch 24.

In this way, when the wiper motor 5 is started and the cam switch 30 is switched from the individual contact 30a to the individual contact 30b, and then the wiper blade returns to the initial position, the cam switch 30 is switched from the individual contact 30b to the individual contact 30a again. , The processing circuit 12 stops outputting the driving signal. As a result, the brake current flows to the low-speed power input terminal 5a of the wiper motor 5 through the contacts 30a and 30c, the contacts 28a and 28c of the relay switch 28, and the contacts 24c and 24b of the relay switch 24, and the wiper motor 5 stops. I do.

When the wiper motor 5 is driven at a high speed, the processing circuit 12 outputs a drive signal from the output terminals P1 and P2, whereby the transistors Tr1 and Tr2 are output.
Are conducted, the relay coils 22 and 27 are both excited, the relay switch 24 is conducted to the individual contact 24b, and the relay switch 28 is conducted to the individual contact 28b. Thus, the electric power from the battery 23 is supplied to the high-speed power input terminal 5b of the wiper motor 5 via the relay switches 28 and 24.

The processing circuit 12 detects from the output voltage level of the cam switch 30 whether or not the wiper blade has returned to the initial position. Until the wiper blade returns to the initial position, the processing circuit 12 outputs the signal from the output terminals P1 and P2. Continue to derive drive signals. Thus, the wiper motor 5 can be driven at a low speed and a high speed.

FIG. 4 is a flowchart for explaining the above-described automatic wiper control operation. Step n
At 1, initialization processing of the integrated value M1 and the count value Wa of the counter 32 is performed. In step n2, the value Ma corresponding to the pulse width W1 of the raindrop pulse is added to the integrated value M1, the integrated value M1 is updated, and the integrating operation is performed. In step n3, it is determined whether or not the integrated value M1 is equal to or greater than the threshold value RP. Otherwise, in step n4, it is determined whether or not the integrated value M1 is equal to or greater than the auxiliary determination level RA. Otherwise, proceed to step n5,
After the count value Wa is reset to 0, the process returns to step n2.

The integrating operation is performed as described above. When the integrated value M1 becomes equal to or more than the threshold value RP in the above-mentioned step n3, the process proceeds to step n6, and the processing circuit 12 outputs the output terminal P1,
The drive signal is selectively output from P2 to drive the wiper motor 5 to perform the wiping operation. In step n7,
After the integrated value M1 is reset to zero, the process returns from step n5 to n2, and the integrating operation is performed again.

In step n4, the integrated value M
When 1 is equal to or higher than the auxiliary determination level RA, the step n
8, the count value Wa of the counter 32 is added, and a count operation is performed. In step n9, it is determined whether the count value Wa has become equal to or longer than the predetermined time W2, and if not, the process proceeds to step n2. Returning, the integration of the integrated value M1 and the time W2 is performed, and if so, the process proceeds to step n6 where the expectation control of the wiper motor 5 is performed.

In this way, it is possible to reduce the influence of variations in raindrops due to the narrow detection range of the raindrop sensor 4 and to reduce the influence of missing raindrops without setting the raindrop detection sensitivity unnecessarily high. The wiper motor 5 can be driven at an optimum wiping interval that matches the driver's feeling.

[0032]

As described above, according to the present invention, an auxiliary discrimination level equal to or less than the threshold value is provided, and when the integrated value of the raindrop pulse exceeds this auxiliary discrimination level, the wiper blade is wiped after a predetermined time has elapsed from that point. Since the operation is performed, even if the variation of the raindrop or the reading error occurs due to the narrow detection range of the raindrop sensor, the timing is almost the same as when the integration was performed without the reading error occurring. Since the wiping operation is performed, without setting the raindrop detection sensitivity unnecessarily high, the influence of the narrow detection range of the raindrop sensor is reduced, and the wiper blade is moved at the optimum wiping interval that matches the driver's feeling. Can be driven.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a wiper control device 1 according to one embodiment of the present invention.

FIG. 2 is a waveform diagram showing an output pulse of a raindrop sensor 4 and a change in an integrated value M1 accompanying the output pulse.

FIG. 3 is a waveform chart for explaining an integration operation at the time of expectation control.

FIG. 4 is a flowchart for explaining an automatic wiper control operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiper control apparatus 2 Auto wiper switch 3 Control circuit 4 Raindrop sensor 5 Wiper motor 12 Processing circuit 32 Counter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-90465 (JP, A) JP-A-63-78849 (JP, A) JP-A-63-159160 (JP, A) 7641 (JP, A) JP-A-1-26044 (JP, A) JP-A 64-9865 (JP, U) JP-A 61-68952 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60S 1/08

Claims (4)

(57) [Claims] 1. A raindrop sensor for detecting a rainfall state, a driving means for reciprocatingly driving a wiper blade on a surface to be wiped, an output signal from the raindrop sensor is integrated, and the integrated value is equal to or greater than a predetermined threshold. Control means for driving the driving means at the earlier of the time when the predetermined time has elapsed and the time when a predetermined time has elapsed from the time when the integrated value has become equal to or greater than the predetermined auxiliary determination level equal to or less than the threshold. And a wiper control device. 2. A raindrop sensor for detecting a rainfall state, a driving means for reciprocatingly driving a wiper blade on a surface to be wiped, and a pulse width of an output signal from the raindrop sensor, wherein the integrated value is a predetermined value. The driving means is driven at the earlier of the time when the integrated value becomes equal to or more than the threshold value and the time when a predetermined time elapses from the time when the integrated value becomes equal to or more than the predetermined auxiliary determination level equal to or less than the threshold value. A wiper control device comprising control means. 3. The wiper control device according to claim 1, wherein the predetermined time is set according to an increasing rate of the integrated value. 4. The wiper control device according to claim 1, wherein the predetermined time is set according to the frequency of occurrence of an output signal from the raindrop sensor.