JPS6331848A - Water flow sensitive window wiper - Google Patents

Abstract

PURPOSE:To suppress the operational noise of relay and to achieve a silent operation, by constructing such that the driving of a wiper relay is prohibited during operation of a wiper and allowed only when it is required. CONSTITUTION:A sensor 1 for detecting a waterdrop adhered to a glass surface is provided and an output signal therefrom is fed to a comparison circuit 3 through a feedback circuit 2 functionable to maintain said output at an approximately constant level then compared with a referential level. On the basis of an output from the comparison circuit 3, pulses of predetermined interval are produced from a pulse generating circuit 4, then a wiper relay 7 is controlled through a relay drive circuit 6 according to the output pulses so as to reciprocate a wiper 8 single time. Here, a prohibition circuit 9 for receiving an operating signal of the wiper 8 is provided so as to maintain the signals level at the input terminals of respective circuits 3, 4 at constant levels during the operation of the wiper and to prohibit provision of an output from the comparison circuit 3 to the pulse generating circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a water volume sensitive window cleaner that is used to drive wipers of a vehicle and operates in response to the volume of water.

[Summary of the invention]

The water-sensitive window cleaner according to the present invention drives the wiper by discriminating the signal from the water droplet detection sensor attached to the glass surface of the vehicle at a predetermined level. By inhibiting the output, the wiper relay is prevented from operating by the output from the water droplet detection sensor each time the wiper operates. In this way, the wiper relay can be energized only when necessary to ensure quiet driving.

[Prior art and its problems]

(Prior art) Window cleaners used in vehicles are configured to operate at a predetermined constant speed or intermittently, but the operating speed changes automatically depending on the degree of raindrops attached to the glass surface. It is preferable to make it change. Therefore, for example, as shown in Japanese Patent Application Laid-Open No. 6L-7SQ46, an automatic window washer that detects the amount of raindrops adhering to the window glass and operates the window cleaner in accordance with the detected level. is proposed.

(Problems to be Solved by the Invention) Such an automatic window cleaner requires a water droplet detection sensor to be provided on the sweeping surface of the wiper blade of the window cleaner. However, the water drop detection sensor cannot distinguish between water droplets on the glass surface and the wiper blade, so when the wiper blade passes, the water detection sensor provides a detection output, which causes the wiper to be driven even when the wiper is in operation. There was a drawback that the relay circuit in the section would operate, causing noise when driving.

[Purpose of the invention]

The present invention has been made in view of the problems of conventional automatic window cleaners, and a technical object of the present invention is to prevent the wiper relay from being energized while the wiper is operating.

[Structure and effects of the invention]

(Structure) The present invention is a window cleaner that has a wiper that sweeps the glass surface and removes water droplets that adhere to the glass surface by sweeping,
As shown in FIG. 1, provided in the sweep area of the wiper,
A water drop detection sensor that detects water droplets attached to the glass surface,
A comparison circuit that compares the signal from the water drop detection sensor with a reference level, a pulse generation circuit that generates a pulse for a predetermined period based on the output from the comparison circuit, and the output of the pulse generation circuit is given to drive the wiper relay for a predetermined period of time. a wiper motor that is energized by the wiper relay to drive the wiper; and a prohibition circuit that prohibits output of the comparison circuit based on an operation signal from the wiper motor.
It is characterized by having the following.

(Function) According to the present invention having such characteristics, the comparison output is prohibited by the operation of the wiper motor while the wiper is operating, so the comparison output is not given to the pulse generation circuit and the wiper relay is activated. not be influenced. In addition, if the amount of raindrops is large and the output from the waterdrop detection sensor exceeds a predetermined level even if the wiper is driven, as soon as the prohibition of the comparison output is stopped, an output is given from the comparison circuit and the wiper relay is activated. Driven.

(Effects) Therefore, according to the present invention, the wiper relay is not driven while the wipers are in operation and is driven only when necessary, so that quiet driving can be achieved. In addition, when there is a large amount of rain, a comparison output is given immediately after the wiper is operated, so that the wiper is driven again and the wiper can be driven continuously.

[Explanation of Examples]

FIG. 1 is a block diagram showing the configuration of a water-resistance window cleaner according to an embodiment of the present invention. In this figure, the water droplet detection sensor 1 is a sensor that is installed on the sweeping surface of the wiper blade W of the windshield of a vehicle as shown in FIG. is given to the comparison circuit 3 via the feedback circuit 2.

The feedback circuit 2 has a long time constant so that a constant output can be obtained regardless of the installation state of the water droplet detection sensor 1, and is a circuit that keeps the output almost constant. give. The comparator circuit 3 discriminates the output from the water droplet detection sensor 1 at a predetermined level, and supplies the output to a pulse generation circuit 4 via a diode D1, and further to a low speed emphasizing circuit 5. The pulse generation circuit 4 generates a pulse of a predetermined width based on the output from the comparison circuit 3, and its output is given to the relay drive circuit 6. The relay drive circuit 6 drives the wiper 8 via the wiper relay 7 based on a pulse signal, thereby self-holding the wiper 8 and causing it to reciprocate once. While the wiper 8 is in operation, an operation signal is applied to the inhibition circuit 9. The prohibition circuit 9 keeps the signal levels of the input terminal of the comparison circuit 3 and the input terminal of the pulse generation circuit 4 constant while the wiper 8 is operating, thereby preventing the output from the comparison circuit 3 from being given to the pulse generation circuit 4. It is something to do. Further, when the output from the comparator circuit 3 is continuously applied, the low-speed forcing circuit S applies a signal to the pulse generating circuit 4 in order to force low-speed operation for a certain period of time regardless of subsequent signals.

(Circuit Configuration of this Embodiment) Next, a more detailed configuration of this embodiment will be described with reference to the circuit diagram of FIG. 3. The output given from the feedback circuit 2 is given to the comparator 3a of the comparison circuit 3, and the output is sent to the diode DI and the low speed forcing circuit 5 via a resistor.
is commonly connected to the diode D1 via the diode D2, and the monostable multi-bibreak of the pulse generation circuit 4 is
MM) given to 4a. Monostable multibibreak 4
a is a pulse generator that generates a pulse for a predetermined time T, for example 0.7 seconds, and its output is sent to the relay drive circuit 6 via the monostable multi-bi break 4b and the diode D3.
is applied to the switching transistor, transistor Tr1. The monostable multivibrator 4b is a retriggerable multivibrator, and if the Q output of the monostable multivibrator 4a is not output for a predetermined period of time, for example, 15 seconds, the monostable multivibrator 4b gives an output to the monostable multivibrator 4a.

The output of the transistor Tri of the relay drive circuit 6 is current-amplified by the transistor Tr2 and given to the relay drive transistor Tr3. A relay coil of a wiper relay 7 is connected to the collector of the transistor Tr3. The normally open contact 7a of the wiper relay 7 is grounded, and the normally closed contact 7b is connected to the wiper 8 and the inhibit circuit 9. Also, the common contact 7C is the combination switch 10.
connected to. The combination switch 10 is a two-circuit, four-contact changeover switch consisting of switches 10a and 10b, and the high-speed operation terminal H and low-speed operation terminal of the wiper motor 8M are each connected to one switch 10a,
The INT contact, which is closed during intermittent operation, is connected to the diode D4 of the relay drive circuit 6. Also, the other switch 1
0b has an INT contact and an OFF contact connected in common, and is connected to a common contact 7c of the wiper relay 7.

On the other hand, the relay drive circuit 6 is provided with a wiper starting circuit that operates manually through the INT contact. This has a switching transistor Tr4 whose emitter is connected to the power supply terminal, and whose base is connected to the anode terminal of a diode D4 via a resistor R1 and a capacitor 01'. In addition, a diode D5 is connected to the common connection terminal of the resistor R1 and the capacitor C1 to the power supply, and the diode D4 is connected to the capacitor CI and the diode D4.
A resistor R2 is connected between the common connection points. The collector end of the transistor Tr4 is connected to the base of the transistor Tri via a diode D6. Transistor Tr4
is intermittent operation (set combination switch 10 to I)
When the NT contact is set, the transistor Tri is driven for a predetermined period of time to first operate the wiper 8 via the wiper relay 7. In the wiper motor 8M, when the wiper relay 7 is driven for a predetermined period of time, the wiper terminal is grounded and the wiper motor 8M starts operating, and the self-holding contact is reversed from the illustrated position and the common contact 8c is on the normally open contact 8a side. The wiper operation is performed in one reciprocating motion. The common contact 8C of the wiper 8 is provided to the common contact 7c of the wiper relay 7 and the inhibition circuit 9. The prohibition circuit 9 has a transistor Tr5 that inverts the operation signal that goes to "L" level when the wiper 8 is in operation, and two switching transistors Tr6 and Tr7 that are operated by the output of the transistor Tr5. This control is performed so that the output of the output and low-speed forcing circuit 5 is not applied to the pulse generation circuit 4. The battery 11 is connected to the wiper relay 7 via the ignition switch 2.
It supplies power to wiper 8 and stabilized power supply 1.
3, a constant power supply voltage Vcc is supplied to each part.

(Configuration of Low Speed Forcing Circuit) Next, the configuration of the low speed forcing circuit 5 will be explained with reference to FIG. 4. The output of the comparator circuit 3 is first sent to the transistor Tr8.
given on the basis of. The transistor Tr8 is a switching transistor operated by the comparison output, and its collector is connected to a charging/discharging circuit including a resistor R4, a variable resistor VH2, and a capacitor C2 via a resistor R3 forming a discharge loop. The terminal voltage of capacitor C2 is applied to comparator 21 and output as a negative signal. and comparator 21
The output of is further applied to the base of switching transistor Tr9. The collector of the transistor Tr9 is connected to a resistor R6, a variable resistor V R, and a variable resistor V R, which similarly form a discharge loop.
7 to a charging/discharging circuit consisting of a resistor R8 and a capacitor c3. This discharging time is longer than the discharging time of capacitor C2 (it is assumed to be set in advance). Then, the terminal voltage of capacitor c3 is compared by comparator 22, and is output to pulse generating circuit 4 via diode D2 as the output of low-speed forcing circuit 5. given to.

(Operation of this embodiment) Next, the operation of this embodiment will be explained with reference to waveform diagrams. First, when the combination switch 1° is switched from the OFF state to the INT side, which operates intermittently, the cathode side of the diode D4 is grounded, so the base current flows through the transistor Tr4 until the capacitor C1 is charged, making the transistor Tr4 conductive. . Therefore, the transistor T
ri is driven and Tr2.ri is driven. Wiper relay 7 is energized via Tr3. Then, the common contact 7C is switched to the normally open contact 7a side, the L terminal of the wiper motor 8 is grounded via the combination switch 10 and the wiper relay 7, and the wiper 8 operates for one round trip. Thereafter, when the capacitor C1 is charged, the wiper operation is stopped. If the amount of rain exceeds a predetermined amount, the water droplet detection sensor 1 will output a sensor output as shown in FIG. As shown, a comparison output is generated from the comparison circuit 3.

This output is applied to the monostable multi-bi break 4a of the pulse generating circuit 4 via the diode D1, as shown in FIGS. 5(C) and 5(d), and a signal having a constant time width T is generated. This signal drives three switching transistors Tri to Tr3 via diode D3, and operates wiper relay 7 for a predetermined period of time. Therefore, the low speed operation terminal of the wiper motor 8M is grounded through the two switches 10a and 10b of the combination switch 10, the common contact 7c of the wiper relay 7, and the normally open contact 7a, and the wiper motor 8M is driven. Then, at time t2, the operation starts and the contact 8a is reversed, so
The wiper motor 8M continues to operate automatically even when the wiper relay 7 is turned off, and continues to sweep the surface of the windshield back and forth once. At this time, if the wiper blade W passes around the water droplet detection sensor 1, it will be detected by the water droplet detection sensor 1 as shown in FIG.
), an output exceeding the threshold level Vrefl is obtained, and the comparison circuit 3 provides a comparison output based on it. However, when the wiper motor 8M is in operation,
As shown in FIG. 1, the common contact 8c of the wiper 8 is grounded and the transistor Tr5 is turned off, so a base current is applied to the transistor Tr5 through the diodes D7 and D8.
5. Tr7 becomes conductive. Therefore, the outputs of the comparator circuit 3 and the low speed forcing circuit 5 are grounded and are not supplied to the pulse generating circuit 4.

If the sensor output exceeds the threshold level Vrefl again after time t3 when the wiper 8 stops operating, the comparison output is given to the pulse generating circuit 4, so that the wiper motor 8M is driven. In this way, the wiper 8 is operated according to the amount of raindrops, and the wiper relay 7 is not operated when the wiper blade W passes around the waterdrop detection sensor 1, allowing quiet running.

FIG. 6 is a time chart when the windshield is dirty or has a large amount of raindrops and the sensor output exceeds the darkness value level even after the wiper is operated. In this case as well, when the sensor output exceeds the dark value level at time t4, Fig. 6 (a) to (d)
As shown in FIG. 3, a predetermined pulse is generated by the comparison output, and the wiper relay 7 is driven. Therefore, between times t and th, the wiper 8 operates to sweep the surface of the windshield back and forth once. If the output from the water droplet detection sensor 1 exceeds the threshold level Vrefl when the wiper 8 stops, it is immediately output from the comparison circuit 3 to the pulse generation circuit 4 as shown in FIG. 6(a) to +c+. is given.

Therefore, in such a state, the wiper 8 can be continuously operated at a low speed.

Furthermore, when the number of input pulses to the pulse generation circuit 4 gradually increases as shown in FIG. The terminal voltage is - Figure 7 (b
As shown in 1, the waveform is a discharge for each human input signal. As shown in FIG. 7 (C1, (d)), if the terminal voltage exceeds the threshold level Vref2, the transistor Tr9 becomes conductive and discharges the capacitor C3.
3 will gradually rise to exceed the threshold level Vref3 of the comparator 22. In this case, Figure 7 (
As shown in e), an output is given from the comparator 22 to the pulse generating circuit 4 via the diode D2. By doing this, the subsequent terminal voltage of capacitor C3 will be at the dark value level Vref3.
The wiper 8 can be operated continuously at a constant cycle regardless of the output from the comparator circuit 3 until the following.

On the other hand, since the amount of raindrops is extremely small, the comparison circuit 3 does not give an output to the pulse generation circuit 4, so the monostable multi-by-break 4
When a does not output an output, its output is given to the monostable multi-bi break 4b. Therefore, for example, 15
If no output is obtained from the second pulse generating circuit 4a, an output is given to 43 from the monostable multi-bi break 4b and the wiper motor 8M is energized. In this way, if the combination switch 10 is set to the INT side, the wiper motor will be driven at least once every 15 seconds.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a water flow window cleaner according to an embodiment of the present invention, Fig. 2 is a diagram showing a wiper and water droplet detection sensor attached to the windshield of a vehicle, and Fig. 3 is a diagram showing the configuration of a water droplet detection sensor according to an embodiment of the present invention. FIG. 4 is a circuit diagram showing the configuration of the low-speed forcing circuit, FIGS. 5 and 6 are time charts showing the operation of each part of this example, and FIG. 7 is the detection 3 is a time chart showing the operation of the low-speed forcing circuit when there is a large amount of raindrops. 1---------Water drop detection sensor 2---Feedback circuit 3---------Comparison circuit 4
---Pulse generation circuit 4a, 4b-----1~
Monostable multi-bi break 5--low speed forced circuit 6
-----------Relay drive circuit 7------Wiper relay 8------Wiper 8M・-・
-Wiper motor 9-...Prohibition circuit 10-
・−・−Combination switch 11−−−−−
-・-Battery D1~D8・～・・Diode Trl～Tr9・・・・−Transistor 21
．． 22・-・-・-・Comparator patent applicant Tateishi Electric Co., Ltd. agent Patent attorney Yoshiki Okamoto (and one other person) Figure 2 Figure 5 Figure 6

Claims (1)

[Claims] (1) A window cleaner that has a wiper that sweeps the glass surface and removes water droplets that adhere to the glass surface by sweeping, and a water droplet detector that is provided in the sweep area of the wiper and detects water droplets that adhere to the glass surface. a sensor, a comparison circuit that compares a signal from the water droplet detection sensor with a reference level, a pulse generation circuit that generates a pulse for a predetermined period based on the output from the comparison circuit, and an output of the pulse generation circuit that is provided with the output of the pulse generation circuit. A relay drive circuit that drives a wiper relay for a predetermined period of time, a wiper motor that is energized by the wiper relay and drives the wiper, and a prohibition circuit that prohibits output of the comparison circuit based on an operation signal from the wiper motor. A water volume sensitive window cleaner characterized by having: