JPS59137841A - Rain drop detector of automatic wiper device - Google Patents

Abstract

PURPOSE:To detect rain drops hit on a vibrating plate and to operate a wiper automatically, by elastically holding the vibrating plate on a casing with rubber burning, and providing a vibrating element, which generates an electric signal corresponding to the resonance of the vibrating plate. CONSTITUTION:A rain drop detector 10 is provided with a first base plate 11, which forms a bottom casing, and a second base plate 13, which is bonded and fixed to the bottom surface of the base plate 11 by a sealing agent 12. Flanges 11a and 13a are bonded to the respective plates. A vibrating plate 17 is attached to a part of a circular hole 14a, which is formed on the surface of a cover 14 by the burning of rubber 15 so that the plate is elastically hold. To the lower surface of the vibrating plate 17, a vibrating element 21 is stuck by a bonding agent. In the vibrating element 21, a piezoelectric element 21b is formed on the one surface of, e.g., a conducting plate 21a. An electric signal is generated in correspondence with the resonance of the vibrating plate 17. The electric signal is outputted to a wiper driving circuit through a shielded wire 22, which is soldered to the conducting plate 21a and the piezoelectric element 21b, an integrated circuit 25, which is provided on a printed board 23, a lead wire 28, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a raindrop detector for an automatic wiper device that detects raindrops and automatically operates a wiper.

Several configurations of this type of automatic wiper device have been devised in the past, including one having the system shown in FIG. 1, for example. That is, a vibrating element made of a piezoelectric element, an electrostrictive element, etc. is used as a raindrop detector L, and this vibrating element is attached to the back of a part of the car body that receives raindrops, such as the bonnet, windshield, or roof of a car, and is attached to the said car body part. The vibration generated when raindrops collide is converted into an electrical signal by the vibration element, this electrical signal is amplified by the amplifier 2, and then processed by the control circuit 3. This processed signal is input to the drive circuit 4 and the wipermorph 5 There was something that drove it.

However, with the above configuration, the vibrations of the vehicle body are directly converted into electrical signals by the vibrating element, so vibrations other than raindrops, such as vibrations generated during normal driving, vibrations caused by engine noise, and vibrations generated when opening and closing doors, are There is a problem in that the rewiper device may malfunction by picking up vibration components generated by the rewiper device and converting it into an electrical signal.

Therefore, in order to detect raindrops without going through the vehicle body parts mentioned above, a separate diaphragm is installed that resonates at a predetermined frequency due to colliding raindrops, and the vibrations of this diaphragm are transmitted to a piezoelectric element, an electrostrictive element, etc. A raindrop detector has been developed that uses a vibrating element to convert it into an electrical signal.

Even when using a raindrop detector with such a configuration, it is necessary to ensure that vibration components other than raindrops are not picked up, and that the diaphragm resonates reliably, and that the diaphragm is mounted to be waterproof. It is also necessary to ensure that Therefore, when attaching the diaphragm to the casing, there is a concept of fitting a ring-shaped rubber into a circular hole in the casing and fixing the diaphragm to this rubber with adhesive, but such assembly work is not efficient. They had problems such as poor assembly accuracy, poor rubber adhesion, and poor waterproof properties.

This invention was made in order to solve the above-mentioned problems, and it is possible to reliably generate resonance of the diaphragm, and the diaphragm can be installed easily, and the installation is partially waterproof. The purpose of this invention is to provide a raindrop detector for an automatic wiper device with an improved structure.

A raindrop detector for an automatic wiper device according to the present invention includes a diaphragm that resonates due to colliding raindrops, and a oscillation element that generates an electric signal according to the resonance of the diaphragm, and the diaphragm is attached to a casing by rubber baking. It is characterized by its elasticity.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

2 to 4 are diagrams showing one embodiment of the present invention, and the illustrated raindrop detector 10 includes a first substrate 11 forming the bottom casing of the detector 10, The first board 11 has a flange 13 on its periphery facing upward, and the 1st board 13 has a flange 13a on its periphery facing upward.
It is glued facing downward. Both flanges 11a.

13a is a cover 1 forming the upper casing of the detector 10;
4 is placed on the inner surface of the cover 14, and is bonded at the peripheral portion with rubber 15 baked onto the inner surface of the cover 14, thereby increasing the waterproofness of this portion. In addition, the diaphragm 17 is attached to the same rubber 15 as described above in the circular hole 14a formed on the top surface of the cover 14.
By baking, the diaphragm 17 is elastically held by the cover 14. At this time, the cover 14
A plurality of (four in the illustrated example) claws 14b are formed to protrude into the circular hole 14a to prevent the diaphragm 17 from lowering excessively due to pressure from its upper surface.

The diaphragm 17 shown in the figure has a circular flat plate shape, but
In order to easily change the resonant frequency of the diaphragm 17 to other frequency bands, it is also possible to use an appropriate shape, for example, one provided with concentric nodes.

Then, a vibrating element 21 having a piezoelectric element 21b formed on one side of a conductive plate 21a is attached to the lower surface of the diaphragm 17 with adhesive, so that an electric signal corresponding to the resonance of the diaphragm 17 can be generated. . This electrical signal is transmitted to the conductive plate 21
The integrated circuit 25.a and the piezoelectric element 21b are guided by shielded wires 22 soldered to the piezoelectric element 21b, respectively, and are provided on a printed circuit board 23 attached to the first substrate 11. The electrical signal from the shield wire 22 is input to an amplifier and control circuit consisting of a capacitor 26, a resistor 27, etc., and then the lead wire 28
and is output to a wiper drive circuit (not shown). In addition, the first substrate 11, the second substrate 13. The cover 14 is made of a conductive material, and by reliably grounding the cover 14 through the lead wire 29, external noise is prevented from entering the raindrop detector IO.

The lead wire 28 is guided to the outside in a watertight manner by a rubber grommet 31 that is continuously fixed to the first substrate 11. In addition, the downward protrusion 13b formed on the No. 1 substrate 13
Bracket 3 is installed between the rubber grommet 31 and rubber grommet 31.
2 can be fitted and fixed, and the mounting is done using the bracket 32.
A double-sided adhesive tape 33 is attached to the lower surface of the holder so that it can be fixed to the body of an automobile. That is, after the raindrop detector 10 is once fixed to the vehicle body part of the automobile, when the raindrop detector 10 is removed for reasons such as repair, the mounting bracket 32 is left on the vehicle body part and the projection part 13b of the No. 1 board 13 is removed. The engagement is released at the rubber grommet 31.

Therefore, 5. In the raindrop detector 10 configured in this way, the diaphragm 17 is fixed to the circular hole 14a of the cover 14 forming the casing by baking the rubber 15 at the same time as the rubber 15 is formed. Since the diaphragm 17 is elastically held by the cover 14 by the diaphragm 15, the assembly workability is good and the assembly precision is high, and the diaphragm 17 can be held securely without disturbing its resonance. In addition, the diaphragm 17 can be mounted with high waterproofness in some parts.

It goes without saying that when baking the rubber, it is desirable to clean the surface of the baked portion and to use an appropriate adhesive as needed. Furthermore, as for the rubber, it is a matter of course that in addition to natural rubber and synthetic rubber, appropriate thermoplastic elastomer materials can be used.

As explained above, according to the present invention, since the diaphragm constituting the raindrop detector is elastically held in the casing by rubber baking, the diaphragm can be attached to the casing with reliable workability and mounting accuracy. Along with being,
It is possible to efficiently generate resonance in the diaphragm,
Moreover, the mounting of the diaphragm has great practical value, such as superior waterproofness in some parts.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of an automatic wiper system;
4 to 4 are an explanatory longitudinal cross-sectional view, a plan view, and an explanatory view of the back of a portion of a cover, respectively, of a raindrop detector according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Raindrop detector, 11... No. 2 board (bottom casing), 14... Cover (upper casing), 15
... Rubber, 17 ... Vibration plate, 21 ... Vibration element. Patent applicant Patent attorney representing Jidosha Electric Industry Co., Ltd.
Yutaka Ko Shio

Claims (1)

[Claims] (1) It is characterized by comprising a diaphragm that resonates due to colliding raindrops and a vibrating element that generates an electric signal in accordance with the resonance of the diaphragm, and the diaphragm is elastically held in the casing by rubber baking. Raindrop detector for automatic wiper equipment.