JP2983307B2 - 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 A so-called automatic wiper control device for controlling a wiper operation based on the output of a raindrop sensor integrates detection signals of the raindrop sensor, and starts wiping operation of a wiper blade when the integrated value exceeds a predetermined threshold value. . In a typical prior art, the integration of the detection signal of the raindrop sensor is configured to start from the start of the wiping operation of the wiper blade or from the end of the wiping operation.

FIG. 7 is a timing chart for explaining the operation of a typical conventional wiper control device for starting integration of the detection signal of the raindrop sensor simultaneously with the start of the wiping operation. FIG. 7A shows a temporal change of the integrated value M11, and FIG. 7B shows a temporal change of the operating position of the wiper blade. It is assumed that the rainfall is constant.

At time t11, when the integrated value M11 of the detection signal reaches a predetermined threshold value TH, the wiper blade housed at the initial position starts the wiping operation. The integrated value M11 is reset once with the start of the wiping operation at the time t11, and then restarts the integration of the detection signal from the raindrop sensor.

On the other hand, the wiper blade reaches the turning position at time t12, and returns to the initial position again at time t13. Even after the wiper blade finishes the wiping operation in this way, the detection signal of the raindrop sensor continues to be further integrated, reaches the threshold value TH at time t14, and the same wiper blade wiping operation as described above starts again. Is done.

FIG. 8 is a timing chart for explaining the operation of another conventional wiper control device for starting integration of the detection signal of the raindrop sensor simultaneously with the end of the wiping operation. Like FIG. 7 described above, FIG. 8A shows a temporal change of the integrated value M11 of the detection signal of the raindrop sensor, and FIG.
Indicates a temporal change of the operating position of the wiper blade.

The difference from the prior art shown in FIG. 7 is that the integration of the detection signal of the raindrop sensor is started from time t23 when the wiping operation is completed. That is, at time t21 when the integrated value M11 reaches the threshold value TH.
At time t2, the wiping operation is started, and the wiper blade returns to the initial position again after the turning position at time t22.
Until 3, the integration operation of the detection signal is stopped. This time t23 when the wiper blade returns to the initial position
The wiping operation is started again at time t24 when the integrated value M11 reaches the threshold value TH.

[0008]

On the other hand, the timing at which the wiping operation should be started is optimal when the amount of raindrops adhering to the surface to be wiped reaches a certain amount and obstructs the forward vision. is there. Therefore, in the prior art shown in FIG. 7, the raindrop integrated between times t11 and t12 is equal to the time t11.
Since it is removed by the wiping operation from t12 to t13, the integrated value is unnecessary for the wiping operation from time t14. Therefore, it is felt that the wiping operation is performed earlier than the timing when the driver feels comfortable.

The prior art shown in FIG. 8 solves the problem of the prior art shown in FIG. 7 in that the integration of the detection signal during the period until the wiper blade reaches the turnback position is stopped. ing. However, since the detection signal is not integrated during the period until the wiper blade returns from the folded position to the initial position, the raindrop attached to the area where wiping is completed after the wiper blade is folded is not integrated, and the driver is not integrated. There is a problem that the wiping operation is performed later than the feeling of the user.

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

[0011]

SUMMARY OF THE INVENTION The present invention provides a raindrop sensor for detecting a rainfall condition, a driving means for reciprocatingly driving a wiper blade for removing raindrops adhered on a surface to be wiped, on the surface to be wiped, Detecting means for detecting whether or not the wiper blade is performing a wiping operation; and in response to outputs of the raindrop sensor and the detecting means, at a time when a predetermined time has elapsed since the wiper blade started the wiping operation. The value based on the output of the raindrop sensor is converted to about 1/2 to start integration, and after the wiper blade finishes the wiping operation, the value based on the output of the raindrop sensor is integrated as it is. Control means for outputting a drive signal for wiping the wiper blade to the drive means when the integrated value is equal to or greater than a predetermined threshold value, wherein the predetermined time is Of the required time of wiping operation of the blade 1 /
2 is a wiper control device.

[0012] The time required for the wiping operation of the wiper blade of the present invention is １ ／ of the time required for the previous wiping operation of the wiper blade obtained based on the detection result of the detection means. It is characterized by.

[0013]

According to the present invention, the control means integrates a value based on the output of the raindrop sensor, and outputs a drive signal to the drive means when the integrated value exceeds a predetermined threshold value. Is reciprocated on the surface to be wiped to remove raindrops attached to the surface to be wiped.

The operation of integrating the value based on the output of the raindrop sensor in the control means is performed in response to the output of the detection means for detecting whether or not the wiper blade is performing the wiping operation. From the start of the wiping operation, the operation is suspended until a predetermined time elapses, and after the elapse of the time, until the wiping operation ends, about 1/2 of the value is returned.
Are integrated, and after the wiping operation is completed, the values are integrated as they are.

Therefore, by setting the predetermined time to half of the time required for the wiping operation of the wiper blade, that is, the time until the wiper blade reaches the turning position, the surface to be wiped after the wiping operation of the wiper blade is performed. The amount of raindrops adhering on the top can be accurately detected.

Preferably, the predetermined time is set as follows:
By setting the time required for the last wiping operation of the wiper blade based on the detection result of the detecting means to be about half of the time required for the wiper blade, the change in the battery voltage and the change in the frictional resistance of the wiper blade due to the change in the rainfall amount can be prevented. On the other hand, it is possible to accurately determine the time required to reach the turning position.

[0017]

FIG. 1 is a block diagram showing an electrical configuration of a wiper control device 1 according to one embodiment of the present invention. The wiper control device 1 is used for a vehicle, and when the automatic wiper switch 2 is turned on, the control circuit 3 responds to a detection signal from the raindrop sensor 4 to drive and control the wiper motor 5 as a driving unit. A wiper blade (not shown) is reciprocated on the windshield to perform a wiping operation,
This is a so-called automatic wiper control device.

The raindrop sensor 4 includes, for example, a pair of light receiving and emitting elements, and detects an amount of rainfall based on a change in a light receiving level due to a raindrop passing through an optical path formed by the light receiving and emitting elements. Is a raindrop sensor.
The detection signal of the raindrop sensor 4 is input to the control circuit 3 and shaped into a rectangular wave pulse by the waveform shaping circuit 11 and then processed by a microcomputer or the like.
2 is input. The output of the automatic wiper switch 2 is input to the processing circuit 12 after noise components such as so-called chattering are removed by a waveform shaping circuit 13.

When the automatic wiper switch 2 is turned on, the processing circuit 12 reads the detection signal of the raindrop sensor 4 and sets the operation state of the wiper motor 5. That is, the intermittent operation state is set when the amount of rainfall is small, and the intermittent time is set shorter as the amount of rainfall increases. When the amount of rain exceeds a predetermined level, a low-speed continuous operation state is set. When the rainfall further increases and exceeds a predetermined level, a high-speed continuous operation state is set. Thus, the automatic wiper control is realized.

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. This power line L2 is
It is connected to a high-level terminal of the battery 23.

The power of the battery 23 is also supplied to the processing circuit 12 and the raindrop sensor 4 via a constant voltage circuit 30.

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. Relay 2
The common contact 24c of the first relay switch 24 is connected to the individual contact 28c of the relay switch 28, and the individual contact 24a
Is connected to a low-speed power input terminal 5a of the wiper motor 5.

When the wiper motor 5 is continuously driven at a high speed, the processing circuit 12 outputs a drive signal from the output terminals P1 and P2 to the lines L1 and L3. The line L1
Drive signal of the transistor Tr via the resistors R1 and R2
1 and the drive signal of 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, there is provided a cam switch 30 which is a detecting means. The cam switch 30 is electrically connected to the individual contact 30a when the wiper blade is at the initial position. Is activated, the wiper blade starts the wiping operation, and conducts to the individual contact 30b when the wiper blade leaves the initial position, and when the wiper blade finishes the wiping operation and returns to the initial position again, the individual contact 30a Is conducted.

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.

The wiper control device 1 configured as described above
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. 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,
Power from the battery 23 via the power line L2 is supplied to the low-speed power input terminal 5a of the wiper motor 5 via the contacts 24c and 24a of the relay switch 24.

When the wiper motor 5 is activated and the cam switch 30 is switched from the individual contact 30a to the individual contact 30b and the wiper blade returns to the initial position, the cam switch 30 is switched from the individual contact 30b to the individual contact 30a, and the processing circuit Numeral 12 stops the output of the drive signal.
As a result, the brake current flows through the contacts 30a and 30c from the contacts 28a and 28c of the relay switch 28 to the low-speed power supply input terminal 5a of the wiper motor 5 via the contacts 24c and 24b of the relay switch 24.
Stops.

When driving the wiper motor 5 at 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 responds to the output voltage level of the cam switch 30 and continues to derive the drive signal from the output terminals P1 and P2 until the wiper blade returns to the initial position. Thus, the wiper motor 5 can be driven at a low speed and a high speed.

A timer 32 is built in the processing circuit 12, and the timer 32 is connected to the output terminals P1 and P2.
When the drive signal is output from 2, the timer starts operation,
A predetermined time T1, which will be described later, is measured.

FIG. 2 is a timing chart for explaining the integration operation of the detection signal of the raindrop sensor 4 in the processing circuit 12. It is assumed that the rainfall state is constant. When the processing circuit 12 starts the wiper motor 5 at time t1, the wiper blade starts the wiping operation as shown in FIG. At this time, the timer 32 operates as shown in FIG.
After the time T1 has been set as shown by, the timing operation is started. At this time, the processing circuit 12
As shown in (1), after resetting the integrated value M of the rainfall amount to 0, the integrating operation is suspended.

After the wiper motor 5 is started as described above, at time t2 when the count value of the timer 32 shown in FIG. 2 (2) becomes 0, the wiper blade is shown in FIG. 2 (3). Has reached the turnover position. From this time t2, the processing circuit 12 returns to FIG.
As shown by, the integration is started by １ ／ of the detection signal level of the raindrop sensor 4.

When it is detected from the output voltage level of the cam switch 30 that the wiper blade has completed the wiping operation and has returned to the initial position, as shown in FIG. As shown in FIG.
From the time t3, the detection signal of the raindrop sensor 4 is integrated as it is. Note that the time T1 is the time W1 required for wiping the wiper blade from the time t1 to the time t3.
Is chosen to be 1/2 of At time t4 when the integrated value M reaches the predetermined threshold value TH, as shown in FIG. 2C, the wiping operation of the wiper blade is started, and the timer 32 is set to the time T1 again. .

FIG. 3 is a flowchart for explaining the operation of integrating the detection signals from the raindrop sensor 4 shown in FIG. In step n1, a flag F1 described later is used.
Is reset to 0, the initial value 1 is substituted for the flag F2, and an initialization process is performed. In step n2, it is determined whether or not the wiper blade is performing the wiping operation. If so, that is, at time t2 in FIG.
During the period from 1 to t3, the process moves to step n3.

At step n3, it is determined whether or not the flag F1 is 0. If so, that is, the time t1 immediately after the processing circuit 12 outputs the drive signal from the output terminals P1 and P2. , T4, the process proceeds to step n4. In step n4, the time W1 required for the wiper blade to perform the wiping operation for one reciprocation is set to one of the time W1.
The time T1 of / 2 is set to the count value T as the time limit of the timer 32. At step n5, after the flag F1 indicating that the setting of the time limit of the timer 32 has been completed is set to 1, the routine proceeds to step n6.
When the flag F1 is 1 in step n3, the process directly proceeds to step n6.

At step n6, the count value T of the timer 32 is decremented by one and a count operation is performed.
At step n7, it is determined whether or not the count value T has become zero. If not, that is, at the time t1
During the period from to t2, the process returns to step n2, and the operation of integrating the detection signals from the raindrop sensor 4 is stopped.

In step n7, when the count value is 0, that is, between the time t2 and the time t3, the process proceeds to step n8. At step n8, the count value T
Is set to 1. By setting the count value T to 1 in step n8 in this manner, even when the processing goes through steps n6 and n7 next time, the operation can be shifted to the operation in step n9 and the subsequent steps without returning to step n2.

In step n9, the flag F2 is updated by subtracting 1 from the value. In step n10, it is determined whether or not the flag F2 has become zero. If not, the process returns to step n2. In step n11, 2 is substituted into the flag F2, and the process proceeds to step n22 to be described later, where an integrating operation is performed. That is, when the flag F2 is 1 in the step n10, the reading of the detection result is paused, and when the flag F2 is 0, the operation shifts to the reading operation of the detection result. Thus, about 1/2 of the detection result can be read.

In step n2, when the wiping operation of the wiper blade is not performed, step n21 is performed.
The flag F1 is reset to 0. In step n22, the detection signal Ma of the raindrop sensor 4 is
And the integrated value M is updated.

In step n23, it is determined whether or not the integrated value M has become equal to or greater than a predetermined threshold value TH. If not, the process returns to step n2. If so, the process proceeds to step n24. The drive signal is output to start the wiping operation of the wiper blade, and the process returns to step n2 after the integrated value M is reset to 0 in step n25.

Thus, the wiper control device 1 according to the present invention
Then, the drive signal is output, the wiper blade starts the wiping operation, and the time required to reach the turn-back position W1 / 2
The detection signal of the raindrop sensor 4 is reduced to about 1/2
After the wiper blade finishes the wiping operation, the detection signal of the raindrop sensor 4 is integrated as it is, and the wiper blade completes the wiping operation. The amount can be accurately detected, and the wiper blade can be driven and controlled at an optimum wiping interval that matches the driver's feeling.

Further, the voltage of the battery 23 is read using, for example, an analog / digital converter, and the time W1 required for one reciprocation of the wiper blade is determined with high accuracy based on the read battery voltage. Is also good.

FIG. 4 is a block diagram showing an electrical configuration of a wiper control device 1a according to another embodiment of the present invention. This embodiment is similar to the above-described embodiment, and the corresponding portions have the same reference characters. Is attached. Processing circuit 12a of this wiper control device 1a
Is provided with a timer 32a.
2a measures the actual required time WN from the start of the output of the drive signal from the output terminal P2 to the end of the wiping operation of the wiper blade. The processing circuit 12a sets a half of the measurement result to the timer 32a as the time T1.
Set to.

That is, as shown in FIG.
At time t4, the timer 32 sets the time T1 at time t4, corresponding to the required time WNo of the wiping operation from time t1 to t3.
i is set, and the timer 32 performs a timing operation for this time T1i. However, at time t5 before the time T1i elapses, as shown in FIG. 5C, the wiper blade reaches the turnback position, and at time t4 when a time WNi shorter than the time WNo has elapsed from the time t4.
When the wiper blade returns to the initial position at 6, the time T1 (i + 1) set by the timer 32 at time t7 when the integrated value M shown in FIG. It is shortened as shown in FIG.

This is set to 1 when the driving signal is output from the output terminal P2 of the processing circuit 12a, as shown in FIG.
When the voltage of the cam switch 30 read by the timer 32 becomes a low level and the wiper blade returns to the initial position, the timer 32a performs a timing operation in response to the flag FC which is reset to zero when the wiper blade returns to the initial position. Done.
Thereby, at the start time of the next wiping operation shown at the time t14, the accurate required time WN (i + 1) can be set.

As the initial value of the required time WN, the required time at the time of the initial operation performed when the wiper switch 2 is turned on may be used. Also, during the wiping operation of the wiper blade, the outward path from the initial position to the turning position has a lot of raindrops to be wiped, and the frictional resistance is large. On the other hand, the return path from the turn-back position to the initial position has a small amount of raindrops and a small frictional resistance. Therefore, a value equal to or more than の of the required time WN may be used as the time T1. Further, as the time T1,
For example, using the average value of the last four times of the required time WN,
You may make it correspond to the dispersion | variation of a measurement result.

FIG. 6 is a flowchart for explaining the operation shown in FIG. 5 described above, and is similar to the operation shown in FIG. 3 described above, and the corresponding parts are denoted by the same reference numerals.
In step n1a, the flags F1, FC and the integrated value M
In addition, the count value N of the timer 32a is reset to zero, and the initial value 1 is substituted for the flag F2, thereby performing an initialization process. At step n2, it is determined whether or not the wiper blade is performing a wiping operation. If so, the process proceeds to step n31.

At step n31, the output terminals P1, P2
Then, at step n32, the count value N of the timer 32a is incremented by 1 and updated, and then the process proceeds to step n3.

At step n3, it is determined whether or not the flag F1 is zero.
At 4a, 1/2 of the count value N of the timer 32a obtained as described later is set to the count value T as the time limit of the timer 32. At step n5, a flag F indicating that the setting of the time limit of the timer 32 has been completed.
After 1 is set to 1, the process proceeds to step n6. When the flag F1 is 1 in step n3, the process directly proceeds to step n6.

In step n6, the count value T of the timer 32 is decremented by 1 to perform a counting operation. Thereafter, in steps n7 to n11, the count value T becomes zero as described above, The counting operation is paused until the blade reaches the turning position,
Step n3 until reaching the return position from the return position
In step 3, the detection signal Ma of the raindrop sensor 4 is 1/2 integrated.

At step n34, the flag FC is set to 1
Is determined, and if not, the process proceeds to step n35, where it is determined whether the potential of the common contact 30c of the cam switch 30 detected through the signal processing circuit 31 is at a high level, If so, the process proceeds to step n36, and after the flag FC is set to 1, the process returns to step n2; otherwise, the process directly returns to step n2.

In step n30, the flag FC
Is 1, the process proceeds to step n37, where it is determined whether or not the common contact 30c of the cam switch 30 is at a low level. If so, steps n38 and n39 are performed.
, The flag FC and the count value N are reset to zero, respectively. Further, at step n40, the output terminal P
1, after the output of the drive signal from P2 is stopped, the process returns to step n2.
Return to 2. In this manner, the wiping operation of the wiper blade, the 積 算 integration operation, and the measurement of the required time WN are performed.

In step n2, when the wiping operation of the wiper blade is not performed, step n21 is performed.
The flag F1 is reset to zero. In step n22, the detection signal Ma of the raindrop sensor 4 is
And the integrated value M is updated. In step n23, it is determined whether or not the integrated value M has become equal to or greater than a predetermined threshold value TH.
Then, if so, the process proceeds to step n31 to start the wiping operation of the wiper blade.

As described above, the wiper control device 1 according to the present invention
In a, the required time WN of the wiping operation of the wiper blade is accurately detected, so that the power supply voltage of the battery 23 fluctuates,
Even for the change in the frictional resistance of the wiper blade due to the change in rainfall, the time required to reach the turn-back position can be accurately determined, and the wiper blade is further optimized at the optimum wiping interval that matches the driver's feeling. Can be controlled.

[0056]

As described above, according to the present invention, the accumulation of the value based on the output of the raindrop sensor is suspended until a predetermined time elapses after the wiper blade starts the wiping operation, and after the elapse of the time. From the time till the end of the wiping operation, about 1/2 of the value is integrated. After the end of the wiping operation, the value is integrated as it is. When the integrated value thus obtained becomes equal to or larger than a predetermined threshold value, the wiper is operated. Since the blade is operated for wiping, by setting the time to the time until the wiper blade reaches the turning position, the amount of raindrops adhering to the surface to be wiped after the wiper blade performs the wiping operation can be accurately detected. The wiper blade can be driven at an optimum wiping interval that matches the driver's feeling.

Further, the predetermined time is set to about 1/2 of the time required for the previous wiping operation of the wiper blade obtained based on the detection result of the detecting means, so that the fluctuation of the battery voltage and the amount of rainfall can be reduced. Even with respect to the change in the frictional resistance of the wiper blade due to the change, it is possible to accurately determine the time required to reach the turning position.

[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 timing chart of an embodiment of the present invention for explaining an operation of integrating detection signals of the raindrop sensor 4;

FIG. 3 is a flowchart for explaining an integrating operation shown in FIG. 2;

FIG. 4 is a block diagram showing an electrical configuration of a wiper control device 1a according to another embodiment of the present invention.

FIG. 5 is a timing chart of another embodiment of the present invention for explaining the operation of integrating the detection signals of the raindrop sensor 4.

FIG. 6 is a flowchart for explaining the integration operation shown in FIG. 5;

FIG. 7 is a timing chart for explaining a typical conventional integration operation of a detection signal of a raindrop sensor.

FIG. 8 is a timing chart for explaining another conventional integration operation of the detection signal of the raindrop sensor.

[Explanation of symbols]

 1, 1a Wiper control device 2 Auto wiper switch 3 Control circuit 4 Raindrop sensor 5 Wiper motor 12, 12a Processing circuit 21, 26 Relay 30 Cam switch 31 Signal processing circuit 32, 32a Timer Tr1, Tr2 Transistor

Claims (2)

(57) [Claims] 1. A raindrop sensor for detecting a rainfall state, a driving unit for reciprocally driving a wiper blade for removing raindrops attached to a surface to be wiped on the surface to be wiped, and wherein the wiper blade is in a wiping operation. Detecting means for detecting whether or not there is, a value based on the output of the raindrop sensor at a point in time when a predetermined time has elapsed since the wiper blade started the wiping operation in response to the outputs of the raindrop sensor and the detecting means. Is converted to about を to start integration, and after the wiper blade finishes the wiping operation, the value based on the output of the raindrop sensor is integrated as it is, and the integrated value becomes equal to or greater than a predetermined threshold value. And control means for outputting a drive signal for wiping the wiper blade to the drive means, wherein the predetermined time is determined at the time of the wiping operation of the wiper blade. Wiper control device which is a half of the time. 2. The method according to claim 1, wherein the time required for the wiping operation of the wiper blade is １ ／ of the time required for the previous wiping operation of the wiper blade based on the detection result of the detecting means. The wiper control device according to claim 1, wherein: