JPH05193451A - Method and equipment for controlling wind wiper motor - Google Patents

Abstract

PURPOSE: To keep the smoothness of a glass surface by emitting a light beam on a part of a window glass, a light diffused by raindrops is reflected to an optical sensor which generates an electric signal, based on the detected value, to obtain a signal proportional to the rain intensity, thereby controlling the rotation of a wiper motor. CONSTITUTION: When an IR transmitter 1 irradiates a homogeneous light beam in a direction A, raindrops 4 on a front glass 3 reflect the light in a direction B which is detected by an IR sensor 2, while the raindrops always reciprocally move at an original position, owing to which the light modulation is performed to reflect the light as an alternating light. The bandwidth and the frequency of the alternating light indicate a measure for the number of raindrops on the glass 3, the rain intensity. Based on the bandwidth and the frequency, an evaluation circuit having an RC element 5, a diode 6 and an amplifier 7 forms a signal U/f which is used for the rotation speed control of the wiper motor. The glass surface can be kept smooth, without requirement for providing a foreign body on the glass 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously connecting and controlling the rotational speed of wind wiper motors of automobiles and similar vehicles depending on the number and thickness of raindrops falling on the glass and the method thereof. To a device for carrying out.

[0002]

2. Description of the Related Art It is already known to automatically connect a motor of a windshield wiper of a vehicle at the beginning of rain and automatically control the rotation speed of the motor depending on the intensity of rain. For example, in U.S. patent application P4117945.5, it is known to attach two electrical conductors to a windshield that act as capacitors. The capacitance of this capacitor changes depending on the raindrops falling on the glass. At that time ΔC
Is used to control the rotation speed of the motor.

However, this apparatus has a drawback in that the foreign matter on the glass, that is, the electrically conductive material adhered thereto, has a high risk of damaging the foreign matter on the glass when cleaning the glass from the inside or the outside. ..

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to avoid the above-mentioned drawbacks and to keep the glass unchanged, that is to say to keep the glass surface smooth, resulting in mechanical damage. It is an object of the present invention to provide a method and apparatus for controlling a wind wiper motor that cannot be obtained.

[0005]

According to the present invention, the above-mentioned problems are achieved by: a.
2) is irradiated with a light beam, and the light beam is modulated by raindrops falling on the window glass, and the frequency and amplitude of the modulation depend on the number and thickness of raindrops (4) falling on the window glass (3). C The light beam is diffused by a raindrop (4) and reflected by an optical sensor (2), and d the sensor (2) forms an electrical signal (U / f) from the modulated reflected beam. However, the strength of the electrical signal is determined by the thickness of the falling raindrops, and is solved by configuring the electrical signal for use in a control circuit to control the rotational speed of the wind wiper motor.

The point of the invention is that the glass is first irradiated with a homogeneous light beam, and when this homogeneous light beam on the glass is incident on a water droplet, the light beam is irregularly modulated. This is because water droplets always accidentally change their shapes due to the traveling wind generated and the surface tension of the counteracting water.

This modulated light is diffused and reflected by water droplets. The frequency and amplitude of the modulation are then a measure for the number of rain drops on the glass. That is, it is a measure for the intensity of rain.

A part of the reflected light beam is detected by the sensor. An evaluation circuit is connected downstream to the sensor. In the evaluation circuit, first, the signal caused by the homogeneous light beam is filtered, and the frequency and amplitude of the remaining signal are evaluated as follows. That is, a signal proportional to the intensity of the rainfall is evaluated for use. This signal, after being amplified, is used to control the rotation speed of the wind wiper motor.

In principle, all types of electromagnetic waves (also visible light) can be used for the irradiation of raindrops on the glass, but it is proposed to use, for example, an infrared beam for the irradiation. This infrared beam can advantageously be a homogeneous light. However, it is also possible to use alternating light in which the light waves are modulated by raindrops.

An apparatus for carrying out the method of the invention is I
It consists of an R transmitter and an IR sensor, and these are commonly housed in one casing. This casing is installed inside the vehicle, together with a device for transmitting and receiving information to the windshield. The mounting location is preferably the vehicle roof. Therefore, there is nothing that interferes with the visual field in the line-of-sight direction with the above-mentioned portion. However, other suitable locations can be selected for assembly. At that time, both the irradiation beam and the reflected beam pass through the window glass. However, this does not hinder the operation of the present invention.

[0011]

1 shows an IR transmitter by 1 and an IR sensor by 2. 3 is a windshield. There are raindrops on the windshield 4. The transmitter 1 emits a uniform light beam in the direction of arrow A. The light is reflected by the raindrop 4 in the arrow direction B. But this time it is reflected as modulated alternating light, not as homogeneous light. This modulation takes place in the water droplet 4. That is, raindrops are constantly changed in shape. The running wind hits the raindrops and flattens the waterdrops. Due to its surface tension, raindrops avoid the wind laterally. This process is repeated at the new position, and the raindrop reciprocates to the original position. Therefore, raindrops oscillate back and forth at all times, which causes light modulation.

FIG. 3 is a diagram of the incident uniform light and the reflected alternating light. Here, the bandwidth of the alternating light and its frequency are a measure for the number of water drops on the glass, ie for the intensity of rain.

Both the bandwidth and the frequency are used to form the signal U / f in the evaluation circuit shown in FIG. This signal finally controls the rotational speed of the wind wiper motor.

Specifically, the circuit of FIG. 4 includes an RC element 5 and a diode 6. An amplifier 7 is connected downstream to the diode. A signal U / f is generated at the output of the amplifier. A motor (not shown) is controlled by this signal.

FIG. 2 shows how a device for carrying out the method of the invention can be incorporated inside a motor vehicle. The view from the rear of the car to the windshield is shown. The car roof is indicated by 8. The roof casing 9 contains an IR transmitter and an IR sensor 2. The transmitter illuminates a space-restricted area 12 therethrough between the front seats 10 and 11, from which the modulated beam is reflected to the sensor 2.

[0016]

As described above, the present invention provides a method and apparatus for controlling a wind wiper motor in which a smooth surface of the glass surface is maintained and mechanical damage is not likely to occur.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the method of the present invention.

FIG. 2 is a schematic diagram showing an arrangement of a transmitter unit and a sensor unit in a vehicle.

FIG. 3 is a diagram of frequencies of an irradiation beam and a reflected beam.

FIG. 4 is a block circuit diagram of an evaluation circuit that is subsequently connected to an IR sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IR transmitter 2 IR sensor 3 Windshield 4 Raindrop 5 RC element 6 Diode 7 Amplifier 8 Car roof 9 Casing 10, 11 Front seat 12 Restricted area

Claims (3)

[Claims] Claim: What is claimed is: 1. A method for controlling the connection of a wind wiper motor of an automobile and similar vehicles depending on the number and thickness of raindrops falling on the glass and the automatic speed control of the rotation speed of the motor, wherein: a window glass The spatially restricted area (12) of (3)
B) the light beam is modulated by raindrops (4) falling on the window glass, the frequency and amplitude of the modulation being the number and thickness of raindrops (4) falling on the window glass (3). C, said light beam being diffused by raindrops (4) and reflected by an optical sensor (2), d by said sensor (2) producing an electrical signal (U / f) from the modulated reflected beam. Of the wind wiper motor, wherein the intensity of the electrical signal is determined by the thickness of the raindrops that fall and the electrical signal is used in a control circuit to control the rotational speed of the wind wiper motor. Control method. 2. The method of claim 1, wherein the light beam is an infrared beam. 3. The transmitter (1) and the light beam sensor (2) are housed in one another in a casing (9), which is integrated inside the vehicle, for the application of raindrops and the sensor ( Device for carrying out the method according to claim 1 or 2, wherein the reflection to 2) is performed through a window glass (3).