JPH08152420A - Rain sensor - Google Patents

Abstract

PURPOSE: To achieve a uniform detection sensitivity regardless of the angle of falling rain by providing a detection part where the comb-tooth part of both electrodes are arranged in nearly a radiant shape on the entire surface of a spherical body so that gaps with a nearly equal interval are formed. CONSTITUTION: An electric wire passage 6 is provided at a spherical body 5 so that it passes through an area near the spherical axis, an electric wire connection part 8 in a nearly spherical shape of one electrode 10 is laid out around one exit 7 of the passage 6 on the surface of the spherical body 5, comb-tooth part 9 is arranged in a radiant shape on the entire surface with the connection part 8 as the center, the electric wire connection part 8 in a nearly spherical shape of the other electrode 10 is arranged around the other exit 7a, and a comb-tooth part 9a is arranged in a radiant shape on the entire surface of sphere with the connection part 8 as the center. Further, comb teeth 9 of one electrode 10 and the comb teeth 9a of the other electrode 10 form a gap with mutually the same space. When it rains, rain drops are adhered to the spherical body 5, the adjacent comb teeth 9 and 9a come into contact with each other and the electrostatic capacity of a capacitor increases, an oscillation frequency decreases, and a microcomputer recognizes the rain fall and outputs an operation command.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rain sensor used for windows or the like which are automatically opened and closed by sensing rain or the like.

[0002]

2. Description of the Related Art A conventional one of this type is disclosed in JP-A-62-1.
Japanese Patent No. 63755 discloses an arc-shaped rain sensor. This is a rain sensor that is provided in the windshield wiper wiping portion of a vehicle windshield to detect moisture and actuate the wiper, and the sensor portion is composed of comb-shaped electrodes. This improves the detection sensitivity of water.

[0003]

However, in the above-mentioned conventional example, since the projected area of the sensor portion is different depending on the rainfall angle, the probability of rain adhering to the sensor portion is low, so that the detection sensitivity varies widely. That is, depending on the rainfall angle, it may not be detected immediately. The present invention has been made in view of the above points, and an object of the present invention is to provide a rain sensor having uniform detection sensitivity at any rainfall angle.

[0004]

A rain sensor according to a first aspect of the present invention has a pair of comb-teeth-shaped electrodes, and the comb-teeth portions of both electrodes are formed on the entire surface of the spherical body at the same intervals. It is characterized in that it has a detector arranged substantially radially.

A rain sensor according to a second aspect of the present invention is the rain sensor according to the first aspect, wherein an electric wire passage penetrating in the vicinity of the axis of the spherical body is bored, and an electric wire is inserted into the electric wire passage so that the electric wire is near the entrance of the electric wire. Connect the wire to the other comb-shaped electrode near the exit of one, and extend the comb-tooth part of one electrode in a substantially radial pattern around the exit of the wire so that it extends radially around the entrance of the wire. As described above, the detection unit has the comb teeth of the other electrode.

A rain sensor according to a third aspect of the present invention is the rain sensor according to the first or second aspect, in which an oscillating circuit is installed inside the sphere of the detecting portion.

[0007]

In the rain sensor according to the first aspect of the present invention, since rain can be detected on the entire surface of the sphere, the detection sensitivity is constant regardless of the rainfall angle. Further, since the comb-teeth portions of the pair of comb-teeth-shaped electrodes are arranged so as to form the gaps at the same intervals, the detection sensitivity is constant regardless of the degree of rainfall.

In the rain sensor according to the second aspect of the present invention, since the inlet and the outlet of the electric wire are near the axis of the sphere, the comb tooth portions of the pair of comb tooth-shaped electrodes can be arranged substantially symmetrically in the left-right and up-down directions. The sensitivity variation can be minimized.

In the rain sensor according to the third aspect of the present invention, the oscillating circuit is installed inside the sphere of the detecting portion, so that the space can be saved.

[0010]

FIG. 1 is an explanatory view showing a rain sensor which is an embodiment of the present invention. This rain sensor is composed of a detector 1, a detector mount 2, an electric wire 3 and an oscillator circuit 4. FIG. 2 is a partially enlarged view showing the detection unit of the rain sensor which is an embodiment of the present invention. First, the configuration of the detection unit 1 will be described. The sphere 5 has an electric wire passage 6 penetrating near the axis of the sphere.
Is provided. Each of the pair of comb-teeth-shaped electrodes 10 has a substantially circular electric wire connecting portion 8 and a plurality of elongated comb-teeth portions 9 continuous with the electric wire connecting portion 8. On the surface of the sphere 5, a substantially circular electric wire connecting portion 8 of one electrode 10 is arranged around one outlet 7 of the electric wire passage 6, and at the same time, the electric wire connecting portion 8 is used as a center to radiate comb teeth radially. The part 9 is arranged.
Around the other outlet 7a, a substantially circular electric wire connecting portion 8 of the other electrode 10 is arranged, and a comb tooth portion 9a is radially arranged around the electric wire connecting portion 8 on the entire surface of the sphere. Further, the comb-teeth portion 9 of one electrode 10 and the other electrode 1
The comb tooth portions 9a of 0 are arranged so as to form a gap having the same interval. The material of the sphere 5 may be glass, plastic or the like. The material of the comb-shaped electrode 10 may be copper paste or other metal. After the comb-teeth-shaped electrode 10 is arranged on the surface of the sphere 5, weatherproof coating is applied to these surfaces.

The wire 3 has a pair of comb-teeth-shaped electrodes 10 at its tip.
Is connected to each of the electric wire connecting portions 8 and passes through the electric wire passage 6 inside the sphere and is connected to the oscillation circuit 4 outside the sphere. FIG. 3 is an explanatory diagram showing a configuration of an oscillation circuit of a rain sensor which is an embodiment of the present invention. The oscillation circuit 4 lowers the oscillation frequency by raindrops detected by the detection unit 1 and transmits this to the microcomputer 11 connected to the oscillation circuit 4. FIG.
Inside R shows a resistance value, and C shows the electrostatic capacity of a capacitor. In this case, the comb-teeth-shaped electrode 10 is used as a capacitor.

The detection unit 1 is attached to a daylighting window or the like via the detection unit mounting base 2 and enables the window to be automatically closed when it is raining.

Next, the operation of this rain sensor will be described. When it rains, raindrops are attached to the detection portion 1 of the spherical rain sensor installed outdoors, and are attached to the gap between the comb-tooth portion 9a of one electrode 10 and the comb-tooth portion 9a of the other electrode 10 that is adjacent to the other. And 9a, the capacitance of the capacitor increases. The raindrops may be attached to any part of the entire surface of the sphere of the detection unit 1, but it is necessary that the raindrops be attached to the adjacent comb tooth portions 9 and 9a. Next, the oscillation frequency of the oscillation circuit 4 decreases due to the increase in the capacitance. This will be described. Table 1 shows a relational expression between the oscillation frequency and the capacitance of the capacitor.

[0014]

[Table 1]

Here, f is the oscillation frequency, CT is the capacitance of the capacitor, RT is the resistance value, VTH is the threshold voltage, and VDD is the power supply voltage. Since this relational expression has the capacitance of the capacitor in the denominator, the oscillation frequency will decrease if this increases. The decrease in the oscillation frequency is transmitted to the microcomputer 11 connected to the oscillation circuit 4, and the microcomputer 11 determines that raindrops are attached and outputs an operation command to the load. As a result, when this rain sensor is attached to a daylighting window or the like, the window can be automatically closed when it rains.

FIG. 4 is an explanatory view showing a rain sensor which is another embodiment of the present invention. This rain sensor is similar to the rain sensor shown in FIG. 1 in that it is composed of a detector 1, a detector mount 2, an electric wire 3 and an oscillator circuit 4, but the sphere 5 is hollow and the oscillator circuit 4 is incorporated inside. The points are different. In this case, the same operation as that of the rain sensor shown in FIG. 1 can be ensured while saving space.

[0017]

In the rain sensor according to the first aspect of the present invention, the detection sensitivity is constant regardless of the rainfall angle and the degree of rainfall. Also, sensitivity can be maintained regardless of mounting angle.

In the rain sensor according to the second aspect of the present invention, since the comb-tooth portions of the pair of comb-tooth-shaped electrodes can be arranged substantially symmetrically in the left-right and up-down directions, variations in detection sensitivity can be minimized.

In the rain sensor according to the third aspect of the present invention, space saving can be achieved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a rain sensor that is an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a detection unit of the rain sensor which is one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of an oscillation circuit of a rain sensor that is an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a rain sensor that is another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection part 3 Electric wire 4 Oscillation circuit 5 Sphere 6 Electric wire passageway 9 Comb-tooth part 10 Comb-tooth electrode

Claims (3)

[Claims] 1. A detection part having a pair of comb-teeth-shaped electrodes, wherein the comb-teeth parts of both electrodes are arranged in a substantially radial pattern on the entire surface of the sphere so as to form gaps at the same intervals. A rain sensor. 2. An electric wire passage penetrating in the vicinity of the axis of the spherical body is formed, and the electric wire is inserted into the electric wire passage so that one of the electric wire passages is provided near the entrance of the electric wire.
Connect the electric wire to the other comb-teeth electrode near the exit and extend the comb-teeth part of one electrode in a substantially radial fashion around the entrance of the electric wire The rain sensor according to claim 1, further comprising a detection section in which the comb teeth of the other electrode are arranged. 3. The rain sensor according to claim 1, wherein an oscillating circuit is installed inside the sphere of the detecting section.