JP2933238B2 - Wiper control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Overview The output from a raindrop sensor is integrated, and when the integrated value exceeds a predetermined threshold within a predetermined maximum intermittent time after the end of the previous wiping operation of the wiper blade, or When the integrated value is less than the threshold value at the time when the maximum intermittent time has elapsed, at that time, in the wiper control device that drives the wiper blade, the maximum intermittent time is based on the integrated value and the threshold, When the integrated value is equal to or more than the threshold value within 80% of the maximum intermittent time, the maximum intermittent time is shortened. When the maximum intermittent time set in the previous wiping operation has elapsed, the integrated value is reduced. When it is less than 1/2 of the threshold, for example, the maximum intermittent time is extended. Further, the maximum intermittent time is changed in response to an input operation by the operator from the sensitivity adjusting means.

This makes it possible to adjust the sensitivity, for which it is difficult to obtain a sufficient effect by correcting the output of the raindrop sensor or correcting the threshold value.

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 state.

2. Description of the Related Art Wiper operation is controlled based on the output of a raindrop sensor.
The so-called automatic wiper control device integrates the output of the raindrop sensor and, when the integrated value is equal to or greater than a predetermined threshold, starts the wiping operation of the wiper blade.

In a typical prior art, such sensitivity adjustment of the automatic wiper control device is realized by using a variable resistor in a voltage dividing resistor circuit for generating a threshold voltage and changing the resistance value of the variable resistor. . In another conventional technique, the sensitivity is adjusted by counting pulses from the raindrop sensor by a microcomputer and increasing or decreasing the number of threshold pulses for level discrimination of the counted value.

Problems to be Solved by the Invention In the above-described related art, the detection sensitivity is determined by changing a threshold level. On the other hand, the detection range of the raindrop sensor is extremely narrow as compared with the area of the windshield, and therefore, even in the same rainfall state, variations occur. Furthermore, the state of rain changes every moment.

Therefore, just adjusting the threshold as described above
As a driver's feeling as a driver, a clear improvement in the wiping interval cannot be recognized, and it is difficult to accurately reflect the driver's will.

An object of the present invention is to provide a wiper control device capable of performing sensitivity adjustment that accurately reflects the intention of an operator.

Means for Solving the Problems The present invention provides a raindrop sensor for detecting a rainfall state, a driving means for reciprocatingly driving a wiper blade for removing raindrops attached to the surface to be wiped on the surface to be wiped, and A sensitivity adjusting means operated by a user, and accumulates the output from the raindrop sensor, and the integrated value is previously determined within a predetermined maximum intermittent time adjusted by the sensitivity adjusting means after the end of the previous wiping operation of the wiper blade. The drive means should drive the wiper blade at the earlier of the time when the accumulated value becomes equal to or more than the predetermined threshold and the time when the maximum intermittent time has elapsed while the integrated value is less than the predetermined threshold. And a control means for outputting a drive signal representing the output, and updating the maximum intermittent time based on the output of the sensitivity adjustment means, and the integrated value and the threshold value. This is a wiper control device.

According to the present invention, the control means integrates the output from the raindrop sensor, and determines when the integrated value becomes equal to or greater than a predetermined threshold within a predetermined maximum intermittent time after the end of the previous wiping operation of the wiper blade. And outputting a drive signal to the drive means at the earlier of the time when the maximum intermittent time elapses while the integrated value remains below the predetermined threshold. In response to the driving signal, the driving unit drives the wiper blade to reciprocate on a surface to be wiped such as front glass to remove raindrops and the like attached to the surface to be wiped.

On the other hand, the maximum intermittent time is updated based on the output of the sensitivity adjusting means operated by the operator, and on the basis of the integrated value and the threshold value. That is, for example, when the integrated value is equal to or greater than the threshold value within 80% of the maximum intermittent time, the maximum intermittent time is changed to be shorter, and when the maximum intermittent time has elapsed, the integrated value is reduced to the threshold value. 1/2 of
If it is less than the maximum intermittent time is changed to be longer. Further, when an input is made by the sensitivity adjusting means to set the sensitivity higher, the maximum intermittent time is changed to be shorter.

By changing the maximum intermittent time in this way, sensitivity adjustment that accurately reflects the intention of the operator is performed without being affected by variations in rainfall conditions.

Embodiment FIG. 1 is a block diagram showing an electrical configuration of a wiper control device 1 according to an embodiment of the present invention. The wiper control device 1 is used for a vehicle and has an automatic wiper switch 2.
In response to the output from the raindrop sensor 4, the control circuit 3 drives and controls the wiper motor 5, which is a driving means, and reciprocates a wiper blade (not shown) on the windshield to perform a wiping operation. This is what is called an automatic wiper control device.

The raindrop sensor 4 includes, for example, a pair of light receiving and emitting elements. Based on a change in light receiving level caused by raindrops passing through an optical path formed by these light receiving and emitting elements,
It is an optical raindrop sensor that detects the amount of rainfall. The output of the raindrop sensor 4 is input to the control circuit 3, shaped into a rectangular pulse by a waveform shaping circuit 11, and then input to a processing circuit 12 implemented by a micro computer or the like. The output of the auto wiper switch 2 is input to the processing circuit 12 after a noise component such as so-called chattering is removed by a waveform shaping circuit 13.

Power from the battery 23 is supplied from the power supply line l2 to the respective circuits in the control circuit 3 via the constant voltage circuit 29, including the processing circuit 12. The processing circuit 12 integrates the output of the raindrop sensor 4 when power is supplied from the constant voltage circuit 29 and the auto wiper switch 2 is turned on, and the integrated value M1 is set to a predetermined maximum intermittent time.
The wiper motor 5 is driven at the earlier of the time when the predetermined value exceeds the predetermined threshold RP within T1 and the time when the maximum intermittent time T1 has elapsed while the integrated value M1 remains below the predetermined threshold RP. I do.

As shown in Table 1, the maximum intermittent time T1 can be selected from, for example, three modes of long, medium, and short, and seven steps are set for each mode. Therefore, for example, in the state where the mode is set to the middle mode, when the first step is selected, the wiper motor 5 is set to the high-speed continuous operation state, and when the second step is selected, the wiper motor 5 is set to the low-speed continuous operation state. When the third step is selected, the intermittent operation state is set to 1.5 seconds, and thereafter, 3 seconds in the fourth step, 6 seconds in the fifth step, 12 seconds in the sixth step, and 24 seconds in the longest seventh step. An intermittent operation state is set.

Each of the modes is switched based on the set value of the sensitivity adjustment volume 35 operated by the driver as the operator. The processing circuit 12 outputs a test pulse generation circuit from the output terminal P3 to read the set value of the sensitivity adjustment volume 35.
Outputs a start pulse to 36. The inspection pulse generation circuit 36
Outputs an inspection pulse to the line l11 in response to the start pulse. The inspection pulse is given to the sensitivity adjustment volume 35 via the input circuit 37, from the input circuit 37,
The output of the voltage level corresponding to the set value of the sensitivity adjustment volume 35 is led out to the processing circuit 12 via the line l12.

The test pulse generation circuit 36 includes resistors R11 to R13 and a transistor Tr11, and the start pulse is given to the base of the transistor Tr11 via the resistor R11. The base of the transistor Tr11 is also connected to a high-level power supply line _Vcc via a pull-up resistor R12, and the emitter of the transistor Tr11 is also connected to the power supply line _Vcc . The test pulse output from the collector of the transistor Tr11 is supplied from the resistor R13 to one terminal of the sensitivity adjustment volume 35 via the resistor R14 of the input circuit 37.

The input circuit 37 includes resistors R14 to R16, a capacitor C11,
The transistor Tr12 is included. The other terminal of the sensitivity adjustment volume 35 is grounded, and a capacitor C11 is interposed in parallel with the sensitivity adjustment volume 35 connected in series and the resistor R14. Capacitor C11
Is supplied to the base of the transistor Tr12 via the resistor R15. The collector of the transistor Tr12 is connected to the power supply line V _cc through a pull-up resistor R16.
Connected to the processing circuit 12 via the line l12, and the emitter is grounded.

Accordingly, in response to the starting pulse derived from the output terminal P3 of the processing circuit 12 shown in FIG. 2 (1), the test pulse shown in FIG. Is output. In response to the test pulse, capacitor C11 derives an output voltage as shown in FIG. 2 (3), whereby the collector of transistor Tr12 to processing circuit 12 is shown in FIG. 2 (4). Pulse is output.

In FIG. 2, when the resistance value of the sensitivity adjustment volume 35 is high, as shown between times t1 and t2, the output voltage of the capacitor C11 shown in FIG. Rises in response to the high-level inspection pulse indicated by the following expression, and after the output of the inspection pulse is stopped, the output voltage gradually decreases. Accordingly, the pulse width of the output pulse to the processing circuit 12 shown in FIG.
W1 becomes longer.

On the other hand, when the resistance value of the sensitivity adjustment volume 35 is low, as shown between times t3 and t4, as shown in FIG.
The output voltage of the capacitor C11 rises in response to the test pulse and falls quickly. Accordingly, the pulse width W1 of the output pulse to the processing circuit 12 shown in FIG. 2 (4) becomes short. In this way, the processing circuit 12 sets the mode of the maximum intermittent time T1 based on the pulse width W1 of the pulse input from the input circuit 37 in response to the start pulse output from the output terminal P3. .

Each of the steps is updated each time the wiper motor 5 is driven based on the integrated value M1 and the threshold value RP. That is, for example, when the integrated value M1 is equal to or more than the threshold value RP within 80% of the set maximum intermittent time T1, the step of the maximum intermittent time T1 is set lower by one step, and the intermittent time is changed to be shorter. Is done.

On the other hand, if the integrated value M1 is less than 1/2 of the threshold value RP at the time when the maximum intermittent time T1 has elapsed, the step of the maximum intermittent time T1 is changed by one step. By performing the operation of updating the maximum intermittent time T1 and the operation of integrating the output of the raindrop sensor 4, 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 to the line 13 from the output terminal P2. This drive signal is given 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 line l2 via the relay coil 27 of the relay 26.

On the other hand, the relay switch 28 of the relay 26 has two individual contacts 28a and 28b, one individual contact 28b is connected to the power line l2, and the other individual contact 28a is connected to the line l4.
Through a common contact 30c of the cam switch 30. Also, the common contact 24c of the relay switch 24 of the relay 21
Is connected to the common contact 38c of the relay switch 38, and the individual contact 24a 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 of the line l1 is input to the base of the transistor Tr1 via the resistors R1 and R2.
Is input to the base of the transistor Tr2 via the resistors R3 and R4.

The emitter of the transistor Tr1 is grounded,
The collector is connected to the power line l2 via the relay coil 22 of the relay 21. Relay 21 relay switch
One of the individual contacts 24b is connected to a high-speed power input terminal 5b of the wiper motor 5.

A cam switch 30 is provided in connection with the wiper motor 5, and the cam switch 30 is electrically connected to the individual contact 30a when the wiper blade is at the initial position. Starting from the initial position
When the wiper blade ends the wiping operation and returns to the initial position again, it conducts 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 connected to the power line l2.
It is connected to the. The common contact 30c is connected to the individual contact 28a of the relay switch 28 via the line l4, and the potential of the common contact 30c is detected by the processing circuit 12 from the line 15 via the signal processing circuit 31. Have been.

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 conducts, the relay coil 27 is excited, and the contact 28b, 28c of the relay switch 2 conducts. Therefore, the power line l
The output from the battery 23 through the contacts 2b, 2
The power is supplied to the low-speed power input terminal 5a of the wiper motor 5 from the contact 8c via the contacts 24c and 24a of the relay switch 24.

Thus, the wiper motor 5 is started and the cam switch 30 is turned on.
When the switch is changed from the individual contact 30a to the individual contact 30b and then returns to the initial position from the wiper blade, the cam switch 30 switches from the individual contact 30b to the individual contact 30a again, and the processing circuit
12 stops output of the drive signal. As a result, the low-speed power supply input terminal 5a of the wiper motor 5 has the contacts 30a, 30
c, a brake current flows through 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.

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 turned on and the relay coil 2 is turned on.
Both 2 and 27 are excited and the relay switch 24 is an individual contact
Conduction is conducted to 24b, and the relay switch 28 is conducted to the individual contact 28b. As a result, the electric power from the battery 23 is supplied to the high-speed power supply input terminal 5b of the wiper motor 5 via the relay switches 28 and 24.

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

In addition, balls 32 and 33 are built in the processing circuit 12,
The timer 32 starts a timing operation when the drive signal is output from the output terminals P1 and P2, and counts the maximum intermittent time T1. The timer 33 measures the maximum intermittent time T1, and the latest time T1 is set every time the time T1 elapses, and the timer starts counting again.

FIG. 3 is a flowchart for explaining the automatic wiper control operation. When the auto wiper switch 2 is turned on, the process proceeds to step n1, and the flags F1, F11 to F13 described later are set.
And initialization processing such as initialization of the integrated values M1 and M2 and setting of the maximum intermittent time T1 and an initial value.

In step n2, a test pulse is output from the test pulse generating circuit 36, and in step n3, it is determined whether or not the pulse width W1 of the pulse from the input circuit 37 in response to the test pulse is equal to or larger than a predetermined threshold value W11. If so, the process moves to step n4, and the mode is set to the short mode.

In step n3, when the pulse width W1 is smaller than the threshold value W11, the process proceeds to step n5, and it is determined whether or not the pulse width W1 is equal to or larger than the threshold value W12 smaller than the threshold value W11. If so, the process proceeds to step n6. Then, the medium mode is set, and if not, the long mode is set in step n7.

From step n4, n6, n7, the process proceeds to step n8, in which the count value T3 of the timer 32 is incremented by 1 to perform a count operation. In step n9, the count of the timer 32 which has performed the count operation in step n8 is performed. The value T3 is the maximum intermittent time T1
Is determined, and if not, the process proceeds to step n10.

In step n10, the output signals of the raindrop sensor 4 are integrated (integrated values M1, M2). In step n11, the integrated value M1
Is determined to be not less than the threshold value RP, and if so, the process moves to step n12. In step n12, it is determined whether or not the count value T3 from the previous wiping operation until the count value becomes equal to or more than the threshold value RP in step n11 is within 80% of the maximum intermittent time T1.
At n13, a flag F11 for decreasing the step of the maximum intermittent time T1 is set to 1, a flag F12 for holding the step, and a flag F13 for ascending.
And are reset to zero. When the count value T3 exceeds 80% of the maximum intermittent time T1 in step n12, the process proceeds to step n14, where the flag F12 is set to 1 and the flags F11 and F13 are reset to zero.

Thus, after the setting of the flags F11 to F13 is completed in steps n13 and n14, and when the count value T3 has reached the maximum intermittent time T1 in step n9, the step is performed.
In step n15, the maximum intermittent time T1 is updated in the step corresponding to the set flag, and in step n16, the integrated value M1 and the count value T3 are reset to zero.

From step n16, the process moves to step n17.
A drive signal is output from the twelve terminals P1 and P2, and the wiper motor 5 is started. In step n18, the cam switch 3
It is determined whether or not the 0 common contact 30c 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. When the wiping operation starts, the process proceeds to step n19. At step n19, it is determined whether or not the common contact 30c of the cam switch 30 has been switched to the individual contact 30a, that is, whether or not the wiping operation has been completed. When the wiping operation has been completed, the process proceeds to step n20. In step n20, the output of the drive signal is stopped, and after the wiper motor 5 is stopped, the process returns to step n2.

When the integrated value M1 is smaller than the threshold value RP in the above step n11, the process proceeds to step n21, and the count value T
In step n22, it is determined whether or not the count value T2 has reached the maximum intermittent time T1, and if not, the flow returns to step n2.
If so, proceed to step n23.

At step n23, it is determined whether or not the integrated value M2 is less than 1/2 of the threshold value RP. If so, the process proceeds to step n24, where the flag F13 is set to 1 and the flags F11, F12 is reset to zero, otherwise, in step n25, the flag F12 is set to 1 and the flags F11 and F13 are reset to zero.

Then, in step n26, the integrated value M2 and the count value T2
Is performed and the process returns to step n2.

As described above, in the wiper control device 1 according to the present invention, since the sensitivity is adjusted by switching the mode of the maximum intermittent time T1 by operating the sensitivity adjustment volume 35, the driver is not affected by variations in the rainfall state and the like. The wiping interval can be changed to such an extent that it can be sufficiently perceived, and sensitivity adjustment that accurately reflects the driver's will can be performed.

It should be noted that other means such as a switch may be used as the sensitivity adjusting means instead of the volume 35, for example.

Effects of the Invention As described above, according to the present invention, since the sensitivity is adjusted by changing the maximum intermittent time, the operation can be sufficiently perceived without being affected by variations in the rainfall state. The wiping interval can be changed to a certain extent, and the sensitivity adjustment accurately reflecting the intention of the operator can be performed.

[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 for explaining an operation of reading a set value of a sensitivity adjustment volume 35, and FIG. 5 is a flowchart for explaining an automatic wiper control operation. 1. Wiper control device 2. Auto wiper switch,
3 control circuit, 4 rain sensor, 5 wiper motor, 12 processing circuit, 32, 33 timer, 35 sensitivity adjustment volume, 36 inspection pulse generation circuit, 37 input circuit

Claims (1)

(57) [Claims] 1. A raindrop sensor for detecting a rainfall state, a driving means for reciprocatingly driving a wiper blade for removing raindrops attached to a surface to be wiped on the surface to be wiped, and a sensitivity operated by an operator Adjusting means, the output from the raindrop sensor is integrated, and the integrated value is equal to or greater than a predetermined threshold within a predetermined maximum intermittent time adjusted by the sensitivity adjusting means after the end of the previous wiping operation of the wiper blade. A driving signal indicating that the wiper blade should be driven is output to the driving means at a time point or a time point at which the maximum intermittent time has elapsed while the integrated value remains less than a predetermined threshold value. And a control means for updating the maximum intermittent time based on the output of the sensitivity adjustment means and the integrated value and the threshold value.