JPH0374351B2 - - Google Patents

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.

As this type of automatic wiper device, several configurations have been devised in the past, such as one having the system shown in FIG. That is,
A vibrating element made of a piezoelectric element, an electrostrictive element, etc. is used as the raindrop detector 1, and this vibrating element is attached to the back side of a part of the car body that receives raindrops, such as the hood, windshield, or roof of a car, and the raindrops are detected on the car body part. The vibration generated during the collision is exchanged into an electric signal by the vibration element, and this electric 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 to drive the wiper motor 5. There was something that made me want to do it.

However, with the above configuration, the vibration of the vehicle body is directly exchanged into an electrical signal by the vibration 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 wiper device may malfunction by picking up the vibration components generated by the windshield and converting them into electrical signals.

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 exchange electrical signals.

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, that the diaphragm resonates reliably, and that the part where the diaphragm is attached is waterproof. You need to be sure. Therefore, when attaching the diaphragm to the casing, there is a concept of fitting a molded rubber previously processed into a ring shape into a circular hole in the casing, and fixing the diaphragm to this molded rubber with adhesive. It has problems such as inefficiency and lack of assembly accuracy, poor adhesion of the molded rubber, and poor waterproof performance due to capillary action between the casing and the molded rubber. was.

This invention was made in order to solve the above-mentioned problems, and it is possible to reliably generate resonance in the diaphragm, it is easy to install the diaphragm, and it is waterproof at the installation part. It is an object of the present invention to provide a raindrop detector for an automatic wiper device, which has an excellent diaphragm mounting structure with little risk of malfunction.

A raindrop detector for an automatic wiper device according to the present invention includes a diaphragm that vibrates due to colliding raindrops, and a oscillation element that generates an electric signal in response to the vibration of the diaphragm, and is provided between an edge portion of the diaphragm and a diaphragm. A diaphragm is provided in a casing with a diaphragm arrangement hole shaped to form an annular space, and the diaphragm is arranged in a direction substantially flush with the casing surface and to form an annular space between the diaphragm and the diaphragm arrangement hole; The annular space formed between the casing and the diaphragm is connected to the casing by rubber baking, which integrally brings the rubber into close contact with the diaphragm and the casing and molds the rubber itself into a film shape. The baked rubber film provides a waterproof seal, and the diaphragm is elastically held in a direction substantially flush with the casing surface. It is characterized by a configuration that accommodates an amplifier that amplifies the signal.

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

2 to 4 are diagrams showing an embodiment of the present invention, and the raindrop detector 10 shown in the drawings includes a first substrate 11 forming a bottom casing of the detector 10, A first substrate 13 adhesively fixed with a sealant 12 is provided on the bottom of the first substrate 11.
The flange 11a on the peripheral edge of the substrate 13 is oriented upward, and the flange 13a of the first substrate 13 is bonded to the substrate 13 with the flange 13a of the periphery facing downward. Both flanges 11a,
A cover 14 forming the upper casing of the detector 10 is placed over the cover 13a, and a baked rubber 15 is baked onto the inner surface of the cover 14 to be tightly fixed during molding.
The material is bonded at the peripheral edge using a method of adhesive bonding to improve waterproofness in this area. Further, the diaphragm 17 is attached to the circular diaphragm arrangement hole 14a formed on the upper surface of the cover 14 by molding and adhering the same rubber 15 as described above, and the diaphragm 17 is attached to the diaphragm arrangement hole 14a and the diaphragm The annular space formed between the cover 14 and the diaphragm 17 is waterproof and sealed by the rubber 15 baked into the membrane shape.
7 is elastically held through the film-like rubber 15. At this time, the cover 14 is formed with a plurality of (four in the illustrated example) claws 14b that protrude into the circular diaphragm arrangement 14a, so that the diaphragm 17 is extremely Prevents it from going down.

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 may have an appropriate shape, for example, concentric nodes. It is also possible to use

For example, a conductive plate 2 is placed on the lower surface of the diaphragm 17.
A vibrating element 21 having a piezoelectric element 21b formed on one side of the vibrating plate 1a is attached with an adhesive so that an electric signal corresponding to the resonance of the vibrating plate 17 can be generated.
This electrical signal is transmitted between the conductive plate 21a and the piezoelectric element 21b.
The signals from the shielded wires 22 are led to the amplifier and control circuit consisting of the integrated circuit 25, capacitor 26, resistor 27, etc. provided on the printed circuit board 23 attached to the I-th board 11. An electrical signal is inputted and then outputted through a lead wire 28 to a wiper drive circuit (not shown). Further, the first substrate 11, the second substrate 13, and the cover 14 are made of conductive material, and by reliably grounding the cover 14 through the lead wire 29, external noise is prevented from entering the raindrop detector 10. I have to.

The lead wire 28 is guided to the outside in a watertight manner by a rubber grommet 31 that is baked and fixed to the I-th board 11. Further, the mounting bracket 32 is fitted and fixed between the downward protrusion 13b formed on the first substrate 13 and the rubber grommet 31, and double-sided adhesive tape 33 is pasted on the lower surface of the mounting bracket 32. , so that it can be fixed to the body of a car. That is, after the raindrop detector 10 has been 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 projections 13b and 13b of the first board 13 are removed. The engagement relationship is released at the rubber grommet 31.

Therefore, the raindrop detector 1 configured in this way
0, by providing a film-like rubber 15 by baking in the circular diaphragm arrangement hole 14a provided in the cover 14 forming the casing, the cover 14 and the diaphragm 17 are molded while the rubber 15 itself is molded. Since the diaphragm 17 is tightly fixed and elastically held on the cover 14 by the film-like rubber 15 after baking molding, the assembling workability is good and the assembly precision is high. 1
It is possible to reliably hold the diaphragm 7 without interfering with its resonance, and the mounting portion of the diaphragm 17 can be highly waterproof.

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. Also,
Naturally, as for the rubber, in addition to natural rubber and synthetic rubber, appropriate thermoplastic elastomer materials can be used.

As explained above, according to this invention,
A diaphragm arrangement hole is provided in the casing and has a shape that forms an annular space between it and an edge portion of the diaphragm constituting the raindrop detector, and is oriented substantially flush with the casing surface and with the diaphragm arrangement hole. A diaphragm arranged to form an annular space therebetween and the casing are connected by rubber baking, which integrally brings the rubber into close contact with the diaphragm and the casing, and molds the rubber itself into a film shape. The annular space formed between the casing and the diaphragm is waterproof and sealed by the baked rubber film, and the diaphragm is oriented substantially flush with the casing surface. Retains elasticity with shaped rubber,
Since the casing accommodates an amplifier that amplifies the electrical signal, it is possible to mold the rubber itself and to tightly fix the rubber, casing, and diaphragm, thereby making it possible to easily attach the diaphragm to the casing. The use of molded rubber is not only reliable in terms of performance and mounting accuracy, but also enables efficient generation of resonance in the diaphragm, and extremely good adhesion between the baked rubber and the casing and diaphragm. There is no risk of water intrusion due to capillary action, which is the case when the diaphragm is installed, so the diaphragm mounting area is extremely waterproof. Since the casing holds the diaphragm elastically, there is a film of rubber between the casing and the diaphragm, which has a low elastic modulus, so the effect of vibrations generated on the vehicle body side is extremely small.In addition, the diaphragm Because it is elastically held in almost the same plane as the casing, it is difficult to receive lateral forces, so there is significantly less risk of damage.Furthermore, since the amplifier is housed inside the casing, It has great practical value, such as being less susceptible to external noise.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of one system of an automatic wiper device, and FIGS. 2 to 4 are an explanatory longitudinal cross-sectional diagram, a plan view, and an explanatory diagram of the back side of a cover portion of a raindrop detector according to an embodiment of the present invention. It is. 10... Raindrop detector, 11... Ith board (bottom casing), 14... Cover (upper casing), 14a... Vibration plate arrangement hole, 15... Rubber,
17... Vibration plate, 21... Vibration element.

Claims (1)

[Claims] 1. A diaphragm arrangement that includes a diaphragm that vibrates due to colliding raindrops and a vibration element that generates an electric signal in response to the vibration of the diaphragm, and that forms an annular space between the diaphragm and the edge portion of the diaphragm. A diaphragm is provided with a hole in the casing, and the diaphragm and the casing are arranged so as to be substantially flush with the casing surface and to form an annular space between the diaphragm and the casing. The annular space formed between the casing and the diaphragm is waterproofed by the baked rubber film, which connects the adhesion of the rubber and molds the rubber itself into a film shape by integrally performing rubber baking. The diaphragm is sealed and elastically held by the baked rubber film in a direction substantially flush with the casing surface, and an amplifier for amplifying the electric signal is housed in the casing. Raindrop detector for automatic wiper equipment.