JPH04189650A - Auto-wiper - Google Patents

Abstract

PURPOSE:To prevent the wrong action of a wiper, by providing a rain drop discrimination means which discriminates if a covering object passing within a rain drop sensor inspection sphere is a rain drop or not, and controlling the wiper when it is discriminated that the covering object is a rain drop. CONSTITUTION:An auto-wiper using a rain drop sensor 1 such as an optical rain drop sensor which converts into an electrical signal the change of a light quantity that is in accordance with the size of a rain drop when a cover, that is, the rain drop shuts the optical path of a light beam, calculates a rain quantity on the basis of the degree and frequency of the light quantity that is intercepted within an inspection sphere, and the wiper 2 is driven by deciding the wiper 2 intermittent time or the like. In this instance, a rain drop discrimination means which discriminates whether or not a cover is a rain drop, is provided, and an output signal is sent out to a control means 5 when it is discriminated by this means 4 that a cover is a raindrop. And a control signal driving the wiper 2 on the basis of a rain drop quantity detected by means of the sensor 1 is outputted by means of this control means 5, and the wiper 2 is driven through a wiper drive means 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary of the Invention] The present invention provides a raindrop discriminating means for discriminating whether or not a shielding object passing within a detection area of a raindrop sensor is a raindrop, and determines that the shielding object is a raindrop. This prevents the wiper from malfunctioning by controlling the wiper when the wiper is activated.

[Industrial application field]

The present invention relates to a word wiper equipped with a raindrop sensor.

[Prior art]

An automatic wiper equipped with a raindrop sensor detects the amount of rain using the raindrop sensor, calculates the intermittent time of the wiper, and automatically controls the wiper.

A method for detecting raindrops using a raindrop sensor is a piezoelectric raindrop sensor that converts changes in the collision energy of raindrops into electrical signals, and a method that adjusts the amount of light according to the size of the raindrop when an obstruction, that is, a raindrop, blocks the optical path of the light beam. There are optical raindrop sensors that convert changes into electrical signals. In an automatic wiper using this optical raindrop sensor, the amount of rain is calculated based on the degree and frequency of the amount of light blocked within the detection area, the intermittent time of the wiper, etc. are determined, and the wiper is driven.

[Problem to be solved by the invention]

For example, in the case of an auto wiper equipped with the above-mentioned optical raindrop sensor, the wiper is driven according to the degree and frequency of the amount of light that is blocked, so particles such as dust with a size equivalent to raindrops can block the optical path of the light beam. If they pass through, the amount of light will change in the same way as raindrops, causing malfunctions. In other words, even on a sunny day, the wipers may malfunction due to dust or black smoke emitted from the truck, causing problems such as confusing the driver and damaging the windshield, wiper rubber, etc.

An object of the present invention is to provide an auto wiper that can automatically determine whether it is raining or not and prevent the wiper from malfunctioning.

[Means to solve the problem]

In order to achieve the above object, the present invention, as shown in FIG. and a control means 5 for controlling the wiper 2 according to the amount of raindrops when the raindrop discriminating means 4 determines that the shielding object is a raindrop. It is an automatic wiper.

[Function] When the raindrop discriminating means 4 determines that the shielding object is a raindrop, it sends a signal indicating this to the control means 5.

When the control means 5 detects the above-mentioned signal, it controls the raindrop sensor 1.
A control signal for driving the wiper 2 is output based on the amount of raindrops detected from the wiper 2, and the wiper driving means 3 drives the wiper 2 in accordance with this control signal.

Therefore, if the above-mentioned shielding object is not a raindrop, the control means 5 will not operate and the wiper 2 will not be driven, so that malfunction of the wiper 2 can be prevented.

〔Example〕

Embodiments of the automatic wiper according to the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of a raindrop sensor showing an embodiment of the present invention, and although an optical raindrop sensor is described in this embodiment, the present invention can also be suitably implemented with other types of raindrop sensors. I can do it.

A light emitting element 22 and a light receiving element 23 are provided on the protrusions at both ends of the raindrop sensor body 21. The light-emitting element 22 and the light-receiving element 23 are arranged facing each other so that their optical axes coincide, and the beam emitted from the light-emitting element 22 is received by the light-receiving element 23.

Further, a moisture detection sensor 24 is provided at the center of the raindrop sensor body 21, that is, at a portion where the shielding object through which the detection beam has passed comes into contact with the raindrop sensor body 21. The moisture detection sensor 24 has a resistance value that changes depending on the presence or absence of moisture, for example.

In this embodiment, the raindrop sensor main body 21 and the moisture detection sensor 24 are integrated, but it goes without saying that they may be provided at separate positions.

FIG. 3 is a block diagram showing one embodiment of the present invention,
Components equivalent to those in FIG. 2 are given the same reference numerals. first,
The configuration of this embodiment will be explained.

The light emitting element 22 sends out a pulsed beam to the light receiving element 23 by the LED drive circuit 31. During this beam, that is, when a raindrop passes through the detection area 39 of the raindrop sensor, the amount of light received by the beam changes. In other words, the amplitude of the received beam waveform changes depending on the size of the raindrop.

The received light signal processing circuit 32 is composed of a preamplifier, a detection circuit, a waveform shaping circuit, etc. (not shown), and detects the amount of change in the amount of received light that occurs when a raindrop passes through the detection beam as an amount of amplitude change using the output of the preamplifier. Envelope detection is performed using a detection circuit.

The detected signal is sent to the power control circuit 38 and also to the waveform shaping circuit, where the waveform is shaped into a raindrop signal having a pulse width corresponding to the raindrop diameter, and then the control circuit 3
5.

The light reception signal processing circuit 32 also outputs a signal synchronized with the raindrop signal as a gate signal to the resistance value detection circuit 33 in addition to the output path to the control circuit 35 .

The power control circuit 38 finely adjusts the emission intensity based on the above-mentioned detection signal to prevent variations in raindrop detection sensitivity due to dirt on the light receiving/emitting elements 22, 23, etc. Also,
Since it is not necessary to perform the above-mentioned fine adjustment for shielding objects other than raindrops, this power control circuit 38 operates only while a signal indicating that it is raindrops is input from the resistance value detection circuit 33, which will be described later. conduct.

On the other hand, a moisture detection sensor 24 is provided below the detection area 39, that is, at the center of the raindrop sensor main body 21 in FIG. 2, and a constant current is supplied thereto from a constant current circuit 34. As mentioned above, the moisture detection sensor 24 is composed of a carbon resistor, etc., and when raindrops adhere to this resistor, the electric characteristics, that is, the resistance value decreases due to moisture. Outputs low voltage, and outputs high voltage when there are no raindrops.

The resistance value detection circuit 33, which is a raindrop discrimination means, detects the voltage across the moisture detection sensor 24, that is, the resistance value of the resistor while the gate signal from the above-mentioned light reception signal processing circuit 32 is input, and thereby detects raindrops. It determines whether or not raindrops are detected and outputs a raindrop determination signal.

That is, when the resistance value reaches a predetermined value or less, an "H" signal indicating that the shielding object is a raindrop is sent to the wJ control circuit 35 and the power control circuit 38.

The control circuit 35 is composed of, for example, a microcomputer, and detects a shielding object passing through the detection area 39 based on a raindrop signal input from the light reception signal processing circuit 32 and a raindrop discrimination signal manually input from the resistance value detection circuit 33. A wiper drive intermittent time suitable for the amount of rainfall is calculated only when raindrops are present, and a wiper control signal is sent to the wiper drive circuit 36.

Therefore, when the shielding object is not raindrops, for example, if it is garbage, the above-mentioned processing is not performed.

The wiper drive circuit 36 mainly includes a relay circuit and a wiper motor that drives the wiper 37, and drives the wiper motor by turning on and off the relay in response to a control signal from the control circuit 35 described above.

In the above configuration, by turning on an ignition switch (not shown) and manually turning on the "auto" switch of the wiper, power is supplied to each circuit and its operation is started.

However, the automatic wiper may be put into operation simply by turning on the ignition switch, and fully automatic wiper control may be performed.

Next, the operation in this embodiment will be explained. First, when a raindrop that is a shield passes through the detection area 39, the light reception signal processing circuit 32 sends a raindrop signal to the control circuit 35 based on the magnitude and frequency of the change in the amount of light received caused by the raindrop. On the other hand, since these raindrops adhere to the resistor of the moisture detection sensor 24, the resistance value falls below a predetermined value, and the resistance value detection circuit 33 sends an "H" signal to the control circuit 3, indicating that the shielding object is a raindrop.
Send to 5. Therefore, the control circuit 35 outputs a conventional wiper control signal based on this raindrop signal. Thereby, the wiper drive circuit 36 drives the wiper 37 according to this control signal.

Next, if the shielding object is something other than raindrops, for example, dust, the light receiving signal processing circuit sends a raindrop signal to the control circuit 35 based on the size of this dust as described above. Even if it adheres to the resistor, since there is no moisture, the resistance value does not change and does not fall below the predetermined value mentioned above. Therefore, the resistance value detection circuit 33 sends an "L" signal to the control circuit 35 indicating that the object is a shield other than raindrops. When the control circuit 35 detects this "L" signal, it ignores the raindrop signal even if it is input, and does not control the wiper 37.

That is, the control circuit 35 receives “
The drive of the wiper 37 is controlled only after detecting the "H" signal, that is, the signal indicating raindrops. Therefore,
If there is an obstruction other than raindrops, the wiper 37 will not be activated, preventing the wiper from malfunctioning on a sunny day, without confusing the driver, and without damaging the windshield or the like.

Further, as described above, the resistance value detection circuit 33 outputs the raindrop discrimination signal while the gate signal from the light reception signal processing circuit 32 is being outputted. Even if noise enters the output path to the automatic wiper 35, the resistance value detection circuit 33 does not output a raindrop discrimination signal, so the control circuit 35 does not control the auto wiper. Therefore, the raindrop detection ability is further improved,
Malfunction of the wiper 37 is reliably prevented.

Furthermore, according to the above embodiment, since the resistor has the property of generating heat, the moisture detection sensor 24 also has the function of a heater that quickly evaporates water droplets. Therefore,
For example, when there are raindrops still attached to the resistor after rain, the resistance value detection circuit 33 has a size equivalent to the raindrop in the detection area 39 in order to continue sending out an "H" signal even on a sunny day. If dirt or the like passes through, the automatic wiper will malfunction, but according to this embodiment, water droplets are quickly evaporated by the heater function of the moisture detection sensor 24, so this problem can be solved. That is, by quickly evaporating raindrops attached to the resistor, the detection ability of the resistance value detection circuit 33 can be improved, and malfunctions of the wiper 37 that occur on sunny days can be reliably prevented.

Note that a heater control circuit or the like for controlling the drying of raindrops may be provided as a separate component near the moisture detection circuit 24.

FIG. 4 is a flowchart for explaining the operation of the control circuit 35 mentioned above.

First, when power is applied to the auto wiper, the control circuit 3
5 starts operation and reads a signal from the resistance value detection circuit 33 in step S1.

In step S2, it is determined whether this signal is "H" or "L", that is, whether the shielding object is a water droplet or not. If the signal is "L", there is an obstruction other than water droplets, such as dust, so step 83
The auto wiper processing from to S6 is not performed. Therefore, the control circuit 35 does not control the wiper 37 and does not drive the wiper 37 either. Further, if the signal is "H", the shielding object is not dust or the like but water droplets, so the process advances to step S3, and a series of auto wiper processes described below are performed.

In steps S3 and S4, as described above, the size of raindrops and the frequency of raindrops are detected based on the degree and correlation of changes in the amount of received light. Then, the rainfall intensity, that is, the amount of rain, is calculated from the size and frequency of the raindrops detected in step S5, and step S
In step 6, the intermittent time of the wiper 37 is calculated in accordance with the rain, and a control signal is sent to the wiper drive circuit 36. Then, the process returns to step S1 and the operation is repeated.

〔Effect of the invention〕

As described above, according to the present invention, when the shielding object passing within the detection area of the raindrop sensor is a raindrop, the control means controls the wiper, and when it is not a raindrop, no control is performed. Malfunctions can be prevented.

[Brief explanation of drawings]

Fig. 1 is a principle diagram for explaining the present invention, Fig. 2 is a perspective view of a raindrop sensor showing an embodiment of the invention, Fig. 3 is a block diagram showing an embodiment of the invention, and Fig. 4 is a flowchart for explaining the operation of the control circuit 35 in one embodiment of the present invention. In the figure, 1: raindrop sensor, 2: wiper, 3: wiper drive means, 4: raindrop discrimination means, 5: control means, 24: moisture detection sensor.

Claims (1)

[Scope of Claims] A raindrop sensor that detects the amount of a shielding object within a detection area, a wiper driving means that drives a wiper, a raindrop determining means that determines whether the shielding object is a raindrop, and the raindrop determining means. and a control means for controlling the wiper according to the amount of raindrops when it is determined that the shielding object is a raindrop.