JPH0226062Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a raindrop sensor that detects the presence and amount of raindrops by attaching detection electrodes to the wiper surface and detecting the presence and amount of raindrops based on the change in electrical resistance between the two electrodes due to raindrops. The object of the present invention is to prevent wear of the detection electrodes due to wiping with a wiper, improve durability, and improve detection accuracy by reliably separating raindrops between the electrodes.

The following is an example of the present invention shown in Figures 1 to 3.
This will be explained with reference to the figures. 1 is a window glass, and 2 is a wiper blade for wiping the front surface of the window glass 1. Reference numeral 3 denotes a raindrop sensor provided on the front surface of the windshield 1 above the wiping surface of the wiper, and is composed of a pair of comb-shaped detection electrodes 4 and 5 attached by, for example, printing. These are made of, for example, a conductive paint containing carbon or silver paste, and both detection electrodes 4 and 5 are arranged close to each other with a predetermined distance therebetween. Reference numeral 6 denotes a separation convex portion made of epoxy resin or the like attached to the front surface of the window glass 1 by printing or the like so as to fill the gap between the detection electrodes 4 and 5. The electrodes protrude by a predetermined dimension and also cover the peripheral edges of the detection electrodes 4 and 5,
When the blade 2 wipes the surface of the window glass 1 and comes into sliding contact with the surface of the separation convex portion 6, the blade 2 is spaced apart from the surfaces of the detection electrodes 4 and 5 by a predetermined distance. Reference numerals 7 and 7 are lead wires, one end of each of which is connected to the detection electrodes 4 and 5, and the other end of which is connected to the detection control section 8. Reference numeral 9 denotes a wiper drive section that receives a control signal from the detection control section 8 and drives the wiper.

Next, the operation of this embodiment configured as above will be explained. When the raindrops 10 adhere to the surface of the raindrop sensor 3 and extend over the surfaces of the detection electrodes 4 and 5 via the surface of the separation convex portion 6 as shown in FIGS. 1 and 2, the raindrops 10 The electrical resistance between both detection electrodes 4 and 5 is reduced compared to when no detection electrodes are present, and this is detected by the detection control section 8 and outputs a control signal to the wiper drive section 9, thereby driving the wiper. Then, the wiper blade 2 comes to wipe off the raindrops 10 adhering to the surface of the windshield 1 and the surface of the raindrop sensor 3, and immediately after the wiper blade 2 wipes off the detection electrode 4 of the raindrop sensor 3,
The electrical resistance between blades 5 and 5 increases, which is detected by the detection control unit 8 and outputs a control signal to the wiper drive unit 9. Afterwards, when there are no raindrops 10 attached, the blade 2 is stopped at the stop position. . When raindrops 10 adhere between the detection electrodes 4 and 5 due to rain after being wiped by the blade 2, the wiper is driven again in the same manner as described above. When the number of raindrops 10 adhering to the surface of the raindrop sensor 2 increases or decreases depending on the amount of rainfall, the electrical resistance between the detection electrodes 4 and 5 changes according to the number of raindrops 10, and the detection control unit 8 controls the wiper drive section 9 by outputting a control signal corresponding to the change in electrical resistance described above, so that the operating speed or operating cycle of the wiper is optimized for the amount of rainfall.

According to the above configuration, since the blade 2 does not come into sliding contact with the surfaces of the detection electrodes 4 and 5 when wiping the surface of the raindrop sensor 3, both the detection electrodes 4 and 5 are not worn out and the durability is significantly improved. Then, the separation convex portion 8
covers the peripheral edges of both electrodes 4, 5, the adhesion of these electrodes 4, 5 to the window glass 1 is improved, and better durability can be obtained. Furthermore, when the blade 2 wipes away the raindrops 10 on the separation protrusion 8, the separation protrusion 8 reliably separates the raindrops 10 remaining on the surfaces of the detection electrodes 4 and 5, so that the change in electrical resistance is sufficiently large. Therefore, detection accuracy can also be improved.

FIG. 4 shows another embodiment of the present invention, in which recesses 1a and 1b are formed on the surface of the window glass 1.
are formed in the recesses 1a and 1b, and detection electrodes 4,
5 are disposed opposite each other so that their respective surfaces are flush with the surface of the window glass 1, and a separating convex portion 8 of a predetermined thickness is formed between both the detection electrodes 4 and 5, and the above-mentioned one embodiment It has the same effect as.

As is clear from the above description, the present invention can provide a raindrop sensor with improved durability and improved detection accuracy.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a front view, FIG. 2 is a longitudinal sectional view,
FIG. 3 is a block diagram, and FIG. 4 is a longitudinal sectional view showing another embodiment of the present invention. In the drawing, 1 is the window glass, 2 is the blade,
3 is a raindrop sensor, 4 and 5 are detection electrodes, 6 is a separation protrusion, and 10 is a raindrop.

Claims (1)

[Scope of utility model registration request] A pair of detection electrodes are attached to the wiping surface of the wiper at a predetermined interval, and the electrical resistance between the two electrodes is changed by raindrops that adhere across the two electrodes. A raindrop sensor characterized in that a separation protrusion made of an insulating material is provided between the detection electrodes, protruding from the surface of the detection electrodes and covering the peripheral edges of both electrodes.