JPS59100034A - Automatic wiper apparatus - Google Patents

Abstract

PURPOSE:To prevent a wiper blade from mulfunction by renew setting a reference signal value on the basis of the signal value detected by a raindrop sensor when the wiper blade wipes and passes by a portion of a window glass to be detected. CONSTITUTION:When raindrops attach to a portion of a window glass to be detected, the signal value detected by an optical raindrop sensor 2 becomes lower than the reference signal value of a reference value attaching circuit 9 so that a comparing circuit 4 applies the trigger signal output to a wiper drive section 5. Thus a wiper motor rotates so that a wiper blade wipes once. The signal value detected by the sensor 2 immediately after wiping is held in a sample holding circuit 8 and the reference signal of the sample value minus a certain value is supplied from the reference value attaching circuit 9 to the comparing circuit 4. This reference signal value is little affected by raindrops but only by environment and temperature in which the wiper is used. Thus, the wiper blade is not subjected to mulfunction by change in the environment or the like under which the sensor 2 is used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic wiper device that detects raindrops on a window glass and automatically controls the operation of wiper blades.

As a conventional automatic wiper device, there is, for example, one shown in FIG. This automatic wiper device l includes an optical raindrop sensor 2 that outputs a detection signal of a value corresponding to the amount of raindrops adhering to the detected part of the window glass, a reference signal generation circuit 3 that generates a reference signal, and a raindrop sensor 2. A comparator circuit q that compares the detected signal value from a reference signal value with a reference signal value and outputs a wiper drive signal when the detected signal value becomes less than the reference signal value, and a wiper circuit that operates the wiper blade each time this wiper drive signal is output. It consists of a drive circuit and an optical raindrop sensor.
The device 3 has a light emitting element and a light receiving element, and outputs a detection signal having a value inversely proportional to the amount of raindrops adhering to the detected part.

However, in such a conventional automatic wiper device, the value of the reference signal of the reference signal generation circuit 30, which influences the timing at which the wiper blade starts operating, is fixed or manually set by the driver or the like. Due to changes in the usage environment temperature and deterioration over time, the raindrop sensor 2
When the electrical characteristics of the light-emitting elements and light-receiving elements that constitute the structure change (for example, in the case of a light-emitting diode, the environmental temperature changes from 20°C to tr).

(When the temperature rises to 0C, the light emission output is halved), the detection signal value of the optical raindrop sensor 2 fluctuates, which causes a problem in that the wiper blade malfunctions. For example, even if there are no raindrops attached, the light emitting output of the light emitting element will decrease when the environmental temperature is relatively high, so the detection signal value will be below the reference value, which will cause the wiper blade to malfunction, and the environmental temperature will increase. Since the light emitting output of the light emitting element increases when the value becomes relatively low, the detection signal value does not exceed the reference value even when raindrops are attached, and therefore the wiper blade does not operate.

The present invention has been made by focusing on the above-mentioned problems of the conventional technology, and uses the detection signal value of the raindrop sensor at the time when the wiper blade operates and wipes over the detected part of the window glass, and uses the detection signal value of the raindrop sensor. It is an object of the present invention to solve the above-mentioned problems by providing a configuration that includes means for updating and setting the reference value based on the detected signal value.

The present invention will be explained below based on the drawings.

FIG. 2 is a block diagram showing a first embodiment of an automatic wiper device according to the present invention. In FIG. 2, the same parts as those shown in FIG. 1 are given the same reference numerals, and their explanations will be omitted. The automatic wiper device 6 in FIG. 2 includes an optical raindrop sensor λ, a wiping completion signal generator 7, an automatic correction type reference signal generator IO consisting of a sample hold circuit and a reference value giving circuit 9, a comparator circuit, and a wiper. It consists of a drive section j.

The wiping completion signal generator 7 has a specific circuit configuration as shown in FIG. 3, and includes an auto-stop switch 7a that is switched in conjunction with the wiper motor 5a that constitutes the wiper drive section j, a capacitor C1, and a resistor that constitutes a differential circuit. It consists of R11 diode D1.

Wiper drive part! When the wiper drive relay Sb constituting the wiper motor j is in the off state as shown in FIG.
When the wiper blade (not shown) connected to the wiper motor 3a reaches its rotation limit, the auto stop switch 7a, which switches according to the rotational state (operating state) of the wiper motor 3a, connects the contact C and connects the contact alc. , therefore, the battery voltage 1B is no longer applied to the wiper motor ja, thereby stopping the wiper blade at that position. At this time, a positive pulse wiping completion signal is generated from the output terminal of the diode D1.

When the wiping completion signal from the wiping completion signal generator 7 is applied, the sample hold circuit of the automatic correction type reference signal generator 10 reads and stores the detection signal value of the optical raindrop sensor 2. The reference value providing circuit outputs a value obtained by subtracting a fixed value from the read detection signal value (sample value) as a reference signal.

The reference value providing circuit 9 is composed of a Zener diode z1 and a resistor R2 as shown in FIG. 1, and outputs a reference signal having a value lower by a fixed Zener voltage than the sample value inputted to the Zener diode z1.

The operation of the first embodiment will be explained below.

When raindrops adhere to the detected part of the window glass, the value of the detection signal of the optical raindrop sensor λ becomes less than the value of the reference signal of the reference value giving circuit 90, and a positive trigger signal is output from the comparison circuit DA. is the wiper drive relay for wiper drive unit j! b
to be applied. Therefore, the wiper drive relay jb temporarily enters the O;/ state, and the wiper motor ja begins to rotate.

As the wiper motor 5a rotates, the contact C of the auto stop switch 7a switches to the contact position, so even if the trigger signal applied to the wiper drive relay tb rises and the wiper drive relay jb turns off. , the battery voltage remains applied to the wiper motor ja and 1
, so the wiper motor ta continues to rotate. After that, at the end of the rotation limit of the wiper blade, contact C changes to contact a.
As a result, a wiping completion signal is generated and the wiper motor 5a is stopped. This single wiping operation of the wiper blade uniformly wipes the detected part of the raindrop sensor, and immediately after the wiping, the value of the detection signal of the raindrop sensor is hardly affected by the raindrops, and the usage environment 9 Temperature It can be seen that this is affected only by aging and deterioration. Upon generation of the wiping completion signal, the value of the detection signal is sampled and held in the sample and hold circuit t, and a reference signal having a value obtained by subtracting a certain value from this sampled value is supplied to the reference value providing circuit and the comparator circuit. As raindrops gradually start to adhere to the detected part again, the raindrop sensor 2 outputs a detection signal with a value inversely proportional to the amount of raindrops attached, and this is compared with the reference signal in the comparison circuit. , the value of the reference signal is a value that reflects the operating environment temperature of the raindrop sensor 2 in the relatively recent past, which can be regarded as the same as the current one, and when the detected signal value falls by a certain value from the sample value, the wiper The grade operates for the first time. Therefore, the wiper blade does not malfunction due to changes in the temperature of the environment in which the raindrop sensor is used. Furthermore, since the reference value can be set to a small value, the sensitivity of the raindrop sensor 2 to the adhesion of minute raindrops can also be improved. In the first embodiment, the reference value providing circuit 9 is configured to simply subtract a certain value from the sandal value and output the reference value, but it may also appropriately add a value to compensate for temperature changes, etc. to the sample value. It may be configured to adjust the selection.

FIG. 5 is a block diagram showing another wiping completion signal generator 7' used in the automatic wiper device B of the first embodiment. This wiping completion signal generator 7' consists of a monostable multivibrator 7Ja with a time constant τ1 and a monostable multivibrator 7'b with a time constant τ2. In order to use the wiping completion signal generator 7' having this configuration, it is necessary to input a trigger signal from the comparator circuit as shown by the broken line in FIG. The time constant τ1 of the monostable multivibrator 7'Ia is determined by the time constant τ1 of the raindrop separator 2 after the wiper blade starts operating.
The time constant τ2 of the monostable multivibrator tag is set to be a time width sufficient to trigger the wiper drive unit. There is. According to this wiping completion signal generator 7', the wiping completion signal is supplied to the sample and hold circuit at the time when one wiping time of the wiper blade has elapsed from the time when the trigger pulse is issued from the comparator circuit.

When this is used, there is an advantage that the configuration is simpler than the wiping completion signal generator 7 shown in FIG. 3, and there is no need to change the conventional wiper drive section 5.

FIG. 6 is a structural diagram showing another wiping completion signal generator f used in the automatic wiper device B according to the embodiment.
In Figure (A), the wiper blade //a of the wiper arm that operates to wipe the window glass Il is made of magnetic rubber, and the reed switch /, 2a is installed on the inner side of the window glass 10.
The sensor block 2, which is provided with a sensor block/2 having Reed switches / and la are turned on. A resistor R3 is connected in series to this reed switch/2a as shown in FIG. 4, and when the reed switch/2a is turned on, a wiping completion signal is output. According to , a wiping completion signal is output immediately after the wiper blade //a wipes and passes the detected part of the raindrop sensor/sako, so there is little chance of raindrops adhering immediately after wiping. The detection signal value of the raindrop sensor 2 in the absence of raindrops can be more reliably read into the sample hold circuit t.

FIG. 7 and FIG.
FIG. 2 is a block diagram showing an embodiment and a flowchart for explaining its operation; FIG. In this second embodiment, the sample hold circuit r1 reference value providing circuit and comparison circuit in the first embodiment are constructed by a microcomputer 30, and the other parts have the same construction as the first embodiment.

Here, as shown in FIG. 7, the microcomputer 30 includes an input section 10a, a central processing unit 30b, and an output section 7117C.

It consists of a read-only memory (uoM) 30a and a random access memory (RAM), tOe.

The operation of the second embodiment of the handle will be explained with reference to the flowchart shown in FIG. First, the value of the detection signal of the optical raindrop sensor 2 is read and stored in the IA register. Next, it is determined whether the wiping completion signal generator 7 has issued a wiping completion signal. When the wiping completion signal is issued, the value (reference value) obtained by subtracting the constant value α from the value of the detection signal (sandal value) stored in the A register is set to B.
Store in register. If the wiping completion signal is not issued, B + from the contents of the A register (value of the detection signal).
/subtract the register contents (reference value), and if the difference is negative (
(If there is a certain amount of raindrops attached), a trigger signal is output to the wiper drive unit j. This causes the wiper blade to operate in one sweep. As described above, the operation of the second embodiment is no different from that of the first embodiment.

FIG. 9 is a block diagram showing a part of a third embodiment of an automatic wiper device according to the present invention. The third embodiment is a further improvement of the wiping signal generator 7 (see FIG. 2) in the first embodiment, and other parts are the same as the first embodiment. Wiping completion signal generation unit 13 in the third embodiment
Signals are input from both the wiper operating state signal generator slag and the optical raindrop sensor. This wiper drive state signal generator/l outputs an L level signal (wiper operation state signal) only when the wiper blade is operating. For example, this may be used as the auto stop switch 7a in FIG. 3. When the wiper blade is operating, the C contact is connected to the B contact, so the L
level signal can be extracted. The optical raindrop sensor 2 outputs a detection signal having a value inversely proportional to the amount of raindrops adhering to the detected portion //1) of the window glass ii (see FIG. 10).

FIG. 11 is a diagram showing a detection signal waveform of the raindrop station 2 shown when the wiper blade //a passes the detected portion //b. Normally, the wiping speed V of the wiper blade //a is about 100 cm/sea, and the length l of the detected portion //1) of the raindrop sensor 2 in the wiping direction is about several cm or less. Therefore, the time T required for the wiper blade //a to operate and pass over the detected part //b is approximately t/V, that is, approximately several tens of m5ec or less, and during this time, the wiper blade //a is exposed to raindrops. The raindrop sensor 2 outputs a short pulse P having a pulse width T because the raindrop sensor 2 operates as raindrops cling together. On the other hand, the change in the detection signal value due to the adhesion of raindrops is relatively gradual, and almost no change is observed within about 1 second.

When the wiper operation state signal is inputted, the wiping completion signal generating section /3 generates a wiping completion signal when detecting a short pulse having a pulse width T in the detection signal.

FIG. 12 is a block diagram in which the wiping completion signal generating section 13 of the third embodiment is configured by a microcomputer. The wiping completion signal generator 13 is a wiper operating state signal generator A.
It has an input section /Ja for receiving an operating state signal from the sensor and a detection signal from the optical raindrop sensor 2.Based on these signals, the central processing unit/3b performs judgment processing, and a wiping signal is sent to the output section. /3C is output. In addition, read-only memory (ROM)/? (l and random access memory (RAM)/Je).

Hereinafter, the operation of the third embodiment will be explained with reference to the flowchart shown in FIG.

First, it is determined whether the wiper blade //a is in operation. When the wiper blade //a is in operation, an L-level wiper operation state signal is supplied to the input section /Ja. Next, if the wiper blade //a is in operation (during the wiping operation), the pulse width T is detected in the detection signal from the raindrop sensor 2.
Find the pulse of degree. If this pulse is detected (
(This corresponds to the case where the wiper blade //a wipes over the detected part //b), a wiping completion signal is output. Note that the other operations are the same as in the first embodiment.

As described above, according to the third embodiment, K has the advantage that it is not necessary to provide any special member to obtain the wiping completion signal, and most of the functions can be assigned to the microcomputer.

Furthermore, it goes without saying that the microcomputer used in the second embodiment may be used as the microcomputer in this third embodiment to perform the functions of this third embodiment and the second embodiment.

In addition, if necessary, the electrical connection can be changed so that the value of the detection signal of the raindrop sensor 2 is directly proportional to the amount of raindrops attached, or a trigger can be triggered from the comparator q when the value of the detection signal exceeds the reference value. Needless to say, it can be configured to output a signal.

As described above, according to the automatic wiper device according to the present invention, the detection signal of the raindrop sensor is read at the time when the wiper blade operates and wipes over the detected part of the window glass, and the detection signal value is used as the detection signal. Since we have provided a means to update and set the reference value based on the raindrop sensor, even if the atmospheric characteristics of the elements that make up the raindrop sensor or the operating environment temperature change, the reference value will be changed and set at an interval shorter than the time of the change, ensuring that it is appropriate. Therefore, it has an excellent effect of preventing malfunctions such as the wiper blade operating even though there are no raindrops or the wiper blade not operating even though there are raindrops.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional automatic wiper device, FIG. 2 is a block diagram showing a first embodiment of the automatic wiper device according to the present invention, and FIG. 3 is a complete wiping diagram used in the same embodiment. FIG. 5 is a circuit diagram showing a signal generator, FIG. 5 is a circuit diagram showing a reference value giving circuit used in the same embodiment, and FIG. 5 is a block diagram showing another wiping completion signal generator used in the same embodiment. ,
FIG. 6 (Shu is a structural diagram showing another wiping completion signal generator used in the same embodiment, FIG. 6(B) is a circuit diagram of the wiping completion signal generator, and FIG. 7 is a diagram according to the present invention. FIG. 9 is a circuit diagram showing a second embodiment of the automatic wiper device, FIG. g is a flowchart for explaining the operation of the second embodiment, and FIG. Fig. io is a front view showing the relationship between the wiper blade of the same embodiment and the detected part of the raindrop sensor, and Fig. ii is a block diagram showing the relationship between the wiper blade of the same embodiment and the detected part of the raindrop sensor. Fig. 10 is a block diagram of the wiping completion signal generating section of the same embodiment constructed from a microcomputer, and Fig. 73 is a waveform diagram of the detection signal of the raindrop sensor generated when It is a flowchart diagram. /, 4... Automatic wiper device, 2... Optical raindrop sensor, 3... Reference signal generation circuit, t... Comparison circuit, !
...wiper drive section 1. ta...wiper motor 1. t
b・-・Wiper drive relay, 7+ 7', 71
... Wiping completion signal generator, 7a... Auto stop switch, 7/a, 7/b... Monostable multivibrator, r... Sample hold circuit, 9... Reference value giving circuit, 10.・・Automatic correction type reference signal generator, l
/...Window glass, //a...Wiper blade, //
b... Detected part, 12... Seven sensor block, 12a
... Reed switch, 13... Wiping completion signal generator, /ri... Wiper operation status signal generator, /3a...
Input section, /Jb...Central processing unit, /,? c...
・Output section, /Jd...Read only memory (RO
M), /,? e...Random access remote control I) (
RAM), cl...capacitor, D, -...diode, R1, R2, R3=resistance, zl...Zener diode. Figure 6 (A) CB) Figure 9 Figure 7 Figure 8 Figure 10 Figure 1

Claims (1)

[Claims] A raindrop sensor outputs a detection signal with a value corresponding to the amount of raindrops adhering to the detected part of the window glass, and the detection signal value is compared with a reference value, and if the detection signal value is less than the reference value, the window means for activating a wiper blade on the glass; reading a detection signal value of the raindrop sensor at the time when the wiper blade is activated and wipes over the detected portion of the window glass; and determining the reference value based on the detection signal value. and means for updating settings.