JPH0321504Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a raindrop detector for an automatic wiper device, which is used to detect raindrops and automatically operate the wiper.

(Prior Art) This type of automatic wiper device has been conventionally available in several configurations, including one having the system shown in FIG. 1, for example. That is, raindrop detector 1
A vibrating element made of a piezoelectric element, an electrostrictive element, etc. is used as a vibration element, 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 when raindrops collide with the car body part, There is one in which the generated vibration is converted into an electric signal by the vibrating element, this electric signal is amplified in the amplifier 2, the signal is processed in the control circuit 3, and this processed signal is input to the drive circuit 4 to drive the wiper motor 5. Ta.

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 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 provided 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.

In conventional raindrop detectors having this configuration, the diaphragm is formed from a metal plate, and the diaphragm is attached to a metal or resin cover using rubber baking or adhesive.

However, in such conventional raindrop detectors, it is difficult to assemble the diaphragm to the metal or resin cover, and special considerations are required to maintain waterproofness at the part where the diaphragm is attached. There were some problems, such as whether it was necessary.

(Purpose of the invention) This invention was made to solve the problems of the conventional methods as mentioned above.It has a good raindrop detection function, is easy to assemble, and is also waterproof. The object of the present invention is to provide an excellent raindrop detector for an automatic wiper device.

(Structure of the invention) This invention provides an automatic wiper device equipped with a raindrop detector using a diaphragm that resonates with colliding raindrops and a vibration element that generates an electric signal corresponding to the resonance of the diaphragm. It is characterized by integrally molding a cover that accommodates a circuit section for processing electrical signals and a single diaphragm section out of resin, and that the diaphragm section is provided with protrusions that serve as nodes of vibration on the outer periphery side. .

(Embodiment) FIGS. 2 and 3 are views showing an embodiment of this invention. The same rectangular rubber damper 12 and the rubber damper 1
a substrate 13 that holds the base frame 11 via 2;
A printed circuit board 14 provided on the upper surface of the rubber damper 12 and a circuit section 15 provided on the printed board 14.
and a shield case 1 that shields the circuit section 15.
6, a cover 17 that engages with and suppresses the base frame 111, rubber damper 12, and printed circuit board 14 and accommodates the circuit section 15, and a vibrating element 18 provided on the inner surface of the cover 17. A lead wire 19 connects the element 18 and the circuit section 15.
It has a configuration in which it is connected by.

The illustrated cover 17 is made of synthetic resin and integrally includes a single diaphragm portion 17a, and a vibrating element 18 is provided on the back side of the diaphragm portion 17a.

Further, on the outer peripheral side of the diaphragm portion 17a of the cover 17 made of synthetic resin, there is a protrusion that becomes a node of the diaphragm portion 17a at a desired resonance frequency of a higher order than the basic resonance frequency determined by the outer shape of the diaphragm portion 17a. 17b.

Furthermore, 21 is a lead wire for taking out the output from the circuit section 15, and the raindrop detector 1 is fixed to a raindrop detector mounting surface 23 such as the bonnet of a car, for example, via a double-sided adhesive tape 22.

In the raindrop detector 1 having such a configuration, when a raindrop hits the diaphragm portion 17a integrally formed with the resin cover 17, the diaphragm portion 17a resonates at a predetermined frequency, and the diaphragm portion 17a resonates at a predetermined frequency. An electrical signal corresponding to the resonance is output from the vibrating element 18, and this output is sent to the circuit section 15 via the lead wire 19.
The signal is inputted into the circuit and amplified, and is sent to the outside, that is, the control circuit 3, via the lead wire 21, and is passed through the drive circuit 4 to operate the wiper motor 5 to start the wiper operation.

At this time, on the outer peripheral side of the diaphragm portion 17a,
Since the diaphragm portion 17 has a protruding portion 17b that becomes a node of vibration at a desired resonance frequency of a higher order than the fundamental frequency determined by the outer shape of the diaphragm portion 17a.
Even when the size of a is set wide, it is possible to obtain a relatively high resonant frequency in the ultrasonic range, for example, and in order to obtain a high resonant frequency, the diaphragm portion 17a
There is no need to reduce the external size of the diaphragm 17a, therefore, the probability of rain hitting the diaphragm 17a can be further increased, and the vibrations of the vehicle body, external noise, etc. transmitted through the substrate 13, cover 17, etc. can be further increased. The rubber damper 12 can significantly attenuate the transmission of the noise to the diaphragm portion 17a, thereby preventing the diaphragm portion 17a from resonating even when low-frequency vibrations occur due to vehicle body vibrations or external sounds. This can reduce the number of malfunctions of the wiper device other than during rain.

In addition, since the formation of the diaphragm portion 17a and the protrusion portion 17b in the cover 17 can be performed at the same time, for example, during injection molding of the cover 17, the moldability is significantly superior to that in the case of processing a metal cover. Therefore, weight reduction can also be achieved.

(Effects of the invention) As explained above, according to this invention,
An automatic wiper device equipped with a raindrop detector using a diaphragm that resonates due to colliding raindrops and a vibration element that generates an electrical signal corresponding to the resonance of the diaphragm, which houses a circuit unit that processes the electrical signal. The cover and the single diaphragm are integrally molded from resin, and the diaphragm has protrusions on the outer periphery that act as nodes of vibration. Compared to a case where the diaphragm is attached to a plastic cover using adhesive or rubber baking, it is much easier to assemble, and since the diaphragm is integrally formed with the resin cover, As there is no connecting part between the diaphragm and the cover, there is no need to consider water leakage at the connecting part, so it has a great practical value of being extremely waterproof. have. Furthermore, because of the protrusion, it is possible to obtain a high resonant frequency due to raindrop vibration even when the size of the diaphragm section is made wide, so the outer shape of the diaphragm section is limited to a small size in order to obtain a high resonant frequency. It is possible to increase the probability that rain will collide with the diaphragm portion.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a system of an automatic wiper device, and FIGS. 2 and 3 are a vertical sectional view and an exploded view, respectively, of a raindrop detector according to an embodiment of the invention. 1... Raindrop detector, 2... Amplifier, 3... Control circuit, 4... Drive circuit, 5... Wiper motor, 1
5...Circuit part, 17...Cover, 17a...Vibration plate part, 17b...Protrusion part, 18...Vibration element.

Claims (1)

[Scope of utility model registration request] An automatic wiper device equipped with a raindrop detector using a diaphragm that resonates due to colliding raindrops and a vibration element that generates an electrical signal corresponding to the resonance of the diaphragm, which houses a circuit unit that processes the electrical signal. 1. A raindrop detector for an automatic wiper device, characterized in that a cover and a single diaphragm portion are integrally molded from resin, and a protruding portion serving as a node of vibration is provided on the outer circumferential side of the diaphragm portion.