JP2987241B2 - 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 so-called automatic wiper control device for driving a wiper blade at a wiping interval suitable for the amount of rainfall, in a typical prior art, an output signal from a raindrop sensor is level-discriminated at a predetermined discrimination level, and the discrimination is performed. The wiper blade is driven when a period of time equal to or higher than the level is integrated and the integrated value becomes equal to or greater than a predetermined threshold value.

[0003]

Therefore, in the above-mentioned prior art, when a relatively large raindrop is detected,
The threshold value is exceeded by one or two drops, and the wiping operation is performed. However, when the diameter of the raindrops becomes larger than a certain level, the raindrops attached to the windshield flow down and the forward visibility does not deteriorate so much, whereas, for example, in the case of extremely small raindrops such as drizzle or the raindrops jumped up by a preceding vehicle. However, even if the amount of rainfall is very small, the visibility in the forward direction is extremely deteriorated. For this reason, in the above-described conventional technology, when the raindrop diameter is large, the forward visibility is not deteriorated,
When the wiping operation is performed and the raindrop diameter is small, there is a problem that the wiping operation is not performed even though the forward visibility is deteriorated.

Further, the raindrop sensor is disposed in a vehicle, for example, on a hood or a front grill, away from a windshield, which is an area where a rainfall condition is to be detected. The area is extremely small compared to the area, so that the detection result of the raindrop sensor varies. For this reason, especially when the raindrop diameter is large, the wiping interval greatly fluctuates,
It gives the driver discomfort.

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 feeling of the operator.

[0006]

According to the present invention, a raindrop sensor for deriving an output signal having a level corresponding to the diameter of a raindrop, and a wiper blade for removing raindrops adhering on the wiped surface are reciprocated on the wiped surface. Driving means for driving displacement, first integration means for integrating the output signals of the raindrop sensor to calculate the amount of rainfall, and second integration means for integrating the number of output signals of the raindrop sensor
And the driving means drives the wiper blade when the number integrated by the second integrating means is equal to or greater than a predetermined value when the integrated value obtained by the first integrating means is equal to or greater than a predetermined threshold value. Control means for outputting a drive signal representing power to be output; and when the number integrated by the second integrating means is less than the predetermined value when the integrated value by the first integrating means is equal to or greater than the predetermined threshold value. Is a wiper control device including prohibiting means for prohibiting output of the drive signal.

[0007]

According to the present invention, the output signal from the raindrop sensor is applied to the first integrating means to calculate the amount of rainfall, and is applied to the second integrating means to integrate the number of output signals. The outputs of the first and second integrating means are provided to the control means. The control means provides a drive signal to the drive means if the integrated value by the first integration means is equal to or more than a predetermined threshold value and the number integrated by the second integration means is equal to or more than the predetermined value. In response to the driving signal, the driving unit drives the wiper blade to reciprocate on a surface to be wiped such as a windshield to remove raindrops and the like attached to the surface to be wiped.

Further, according to the present invention, even if the integrated value by the first integrating means is equal to or more than the predetermined threshold, if the number integrated by the second integrating means is less than the predetermined value,
That is, when the number of raindrops is not so large, it is determined that the raindrop integrated value has reached the threshold value only by relatively large raindrops, and the control means stops outputting the drive signal. Thus, when the raindrop diameter is large, the wiping operation can be restricted as compared with a normal raindrop, and the wiping operation can be performed in accordance with the operator's feeling. In addition, a stable wiping operation can be performed without an undesired change in the wiping interval even with respect to a variation in the detection result of the raindrop sensor.

[0009]

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-receiving and light-emitting elements, and detects an amount of rainfall 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. It is a raindrop sensor of a formula.

The output signal of the raindrop sensor 4 is input to the control circuit 3 and is applied to a comparator 41 and a window comparator 42 as comparing means. The comparator 41 includes a comparison circuit C1 and voltage dividing resistors R1a and R1b.
It is comprised including. An output signal from the raindrop sensor 4 is supplied to one terminal of the comparison circuit C1, and a voltage V1 obtained by dividing a high-level voltage + B by the voltage dividing resistors R1a and R1b to the other terminal. Is entered.

Similarly, the window comparator 42
Two comparison circuits C2a and C2b and voltage dividing resistors R2a and R2
b, R2c. Comparison circuit C2a
And the other terminal of the comparison circuit C2b
An output signal from the raindrop sensor 4 is input. The high-level voltage + B is divided by the voltage dividing resistors R2a, R2b and R2c, and the voltage V2a at the connection point between the resistors R2a and R2b is given to the other input of the comparison circuit C2a. The voltage V2b at the connection point between the resistor and the resistor R2c is given to one input of a comparison circuit C2b.

The voltage V1 is set to a relatively high value, for example, 0.4 V, and the voltage V2b is lower than the voltage V1, and is close to the minimum value level of the output signal from the raindrop sensor 4. , For example, set to 0.1V. Further, the voltage V2a is equal to the voltage V2.
It is set slightly higher than b, for example, 0.15V.

Therefore, when the output signal from the raindrop sensor 4 is shown in FIG. 2A, the output signal from the raindrop sensor 4 is output from the comparator 41 as shown in FIG. The raindrop pulse S1 is derived only during the above period. As shown in FIG. 2B, the output signal from the raindrop sensor 4 from the window comparator 42 is equal to or higher than the voltage V2b and the voltage V2a
The raindrop pulse S2 is output only for the following period.

The raindrop pulses from the comparator 41 and the window comparator 42 are realized by a microcomputer or the like, and are input to the processing circuit 12 which is a control means and a prohibition means. The output of the auto-wiper switch 2 is processed by the waveform shaping circuit 13 after removing noise components such as chattering.
2 is input.

Accordingly, in the normal rainfall state shown in FIG. 2, the automatic wiper switch 2 is turned on and detection starts at time t1, and the reference signs q1, q2, q3,.
・ ・ Raindrops are detected as shown in FIG.
2 corresponding to the raindrop pulse S1 shown in (3).
As shown in (4), the pulse width is accumulated. When the integrated value M1 of the integrated pulse width becomes equal to or greater than the predetermined threshold value RP, the wiping operation is performed at time t2 as shown in FIG. 2 (5), and the integrated value M1 is reset to zero.

A predetermined time W from the time t1
2, for example, the number of raindrops detected by the time t3 when 2 seconds have elapsed is six, and therefore the processing circuit 12
Determines that raindrops from the large diameter to the small diameter are uniformly detected, and performs the wiping operation as described above at the time t2 after the time t3.

On the other hand, when the integrated value M1 becomes equal to or more than the threshold value RP, if the number of detected raindrops is less than a predetermined value RN, for example, less than 5, only relatively large raindrops are detected. The wiping operation is prohibited as shown in FIG. FIG. 3 is a timing chart for explaining an operation in a state where the number of raindrops is small and the influence of relatively large raindrops is large.
(1) to (5) correspond to FIGS. 2 (1) to (5) described above, respectively.
It corresponds to.

That is, even if the integrating operation is started from time t11 and the integrated value M1 is equal to or larger than the threshold value RP at time t12, the number of raindrops detected from the time t11 to the time t13 when the time W2 has elapsed is reduced. As shown in FIG. 3B, when the number is less than five,
The wiping operation that should be performed as indicated by the virtual line in (5) is prohibited.

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 the power is supplied from the constant voltage circuit 29 and the auto wiper switch 2 is turned on, the processing circuit 12 integrates the pulse width of the raindrop pulse from the comparator 41 as described above, and the integrated value M1 Is greater than or equal to a predetermined threshold value RP, the wiper motor 5 is driven.

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, and one individual contact 24a of the relay switch 24 is connected to the 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 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. The other 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.
When the wiper blade is at the initial position, the individual contact 30a is electrically connected, the wiper motor 5 is started, the wiper blade starts wiping operation, and when the wiper blade is separated from the initial position, the individual contact 30b is electrically connected. When the blade finishes the wiping operation and returns to the initial position again, it is electrically connected to the individual contact 30a.

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 voltage 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 voltage of the common contact 30c whether or not the wiper blade is performing the wiping operation.

Therefore, 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 24a of the relay switch 24, and the wiper motor 5 stops. I do.

When driving the wiper motor 5 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. At step n1, initialization processing such as resetting the integrated value M1 to zero is performed. In step n2, it is determined whether or not the raindrop pulse S1 is detected by the comparator 41. If so, in step n3, the pulse width Ma of the raindrop pulse S1 is added to the integrated value M1, and the integrated value M1 is calculated. Be updated.

In step n4, the predetermined time W
It is determined whether or not 2 sec, which is 2, has elapsed. If so, in step n5, the control prohibition flag F1 is temporarily determined.
Is set to 1. Further, at step n6, the count value M2 of the number of raindrop pulses S2 from the window comparator 42 is reset to zero, and thereafter, the process proceeds to step n7. Otherwise, the process directly proceeds to step n7.

At step n7, it is determined whether or not the raindrop pulse S2 has been detected. If so, at step n8, the count operation of the count value M2 is performed. At step n9, it is determined whether or not the count value M2 is equal to or greater than the predetermined threshold value RN of 5. If so, the control prohibition flag F1 is reset to zero at step n10, and at step n11, After the count value M2 is reset to zero, the process proceeds to step n12. Otherwise, the process directly proceeds to step n12.

At step n12, it is determined whether or not the integrated value M1 integrated at step n3 is equal to or greater than the threshold value RP. If so, whether or not the control inhibition flag F1 is set to 1 at step n13 If not, that is, if the integrated value M1 is equal to or larger than the threshold value RP while the raindrops from the large diameter to the small diameter are uniformly detected, the process proceeds to step n14. In step n14, the integrated value M1 is reset to zero.

In step n15, a drive signal is selectively output from the terminals P1 and P2 of the processing circuit 12, and the wiper motor 5 is started. In step n16, it is determined whether or not the common contact 30c of the cam switch 30 has been switched to the individual contact 30b, that is, whether or not the wiper blade has left the initial position and has started the wiping operation. Move on to In step n17,
The common contact 30c of the cam switch 30 is
a, that is, whether or not the wiping operation has been completed.
Move to 18. In step n18, the output of the drive signal is stopped, and after the wiper motor 5 is stopped, the process returns to step n2. Further, when the integrated value M1 is smaller than the threshold value RP in the step n15,
When the control prohibition flag F1 is 1 at 16,
It returns directly to step n2.

As described above, the threshold value R is set within the time W2.
Since the wiping operation is performed only when the raindrops of N or more are detected relatively frequently and the integrated value M1 is equal to or more than the threshold value RP, the number of raindrops is small and the integrated value M1 is affected by the large raindrops. Is greater than or equal to the threshold value RP, the wiping operation can be prohibited, the wiping operation for large raindrops with relatively little deterioration in forward visibility is limited, and a wiper control operation that matches the driver's feeling is performed. be able to.

In addition, with respect to variations in detection results due to the narrow detection range of the raindrop sensor 4 and the mounting position, etc.
A stable wiper control operation can be performed.

[0038]

As described above, according to the present invention, the output of the raindrop sensor is provided to each of the first and second integrating means, and the control means controls the integrated value representing the amount of rainfall by the first integrating means. If the number of output signals integrated by the second integrating means is equal to or greater than a predetermined threshold and the number of output signals integrated by the second integrating means is equal to or greater than the predetermined value, the wiper blade is driven, and the integrated value by the first integrating means is equal to or greater than the predetermined threshold. Even if the number accumulated by the second accumulating means is less than the predetermined value, the wiping operation by the wiper blade is prohibited, and thus the wiping operation is performed at the optimal wiping interval that matches the operator's feeling. Can be made. In addition, even if the detection result varies due to the narrow detection range of the raindrop sensor, a stable wiping operation can be performed without undesirably changing the wiping interval.

[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 for explaining an operation during normal rainfall.

FIG. 3 is a timing chart for explaining an operation in a state where the number of raindrops is small.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiper control device 2 Auto wiper switch 3 Control circuit 4 Raindrop sensor 5 Wiper motor 12 Processing circuit 30 Cam switch 41 Comparator 42 Window comparator

Claims (1)

(57) [Claims] 1. A raindrop sensor for deriving an output signal of a level corresponding to a raindrop diameter, a driving unit for reciprocatingly driving a wiper blade for removing raindrops attached to a surface to be wiped on the surface to be wiped, A first integrating means for integrating the output signal of the raindrop sensor to calculate the amount of rainfall; a second integrating means for integrating the number of output signals of the raindrop sensor; Control means for outputting a drive signal indicating that the wiper blade should be driven to the drive means when the number integrated by the second integration means is equal to or more than a predetermined value when the number is equal to or more than the threshold value; Prohibiting means for prohibiting output of the drive signal when the number integrated by the second integrating means is less than the predetermined value when the integrated value of the integrating means becomes equal to or more than the predetermined threshold value. Feature Ipa control device.