JPS5945247A - Intermittent wiper for windshield of vehicle - Google Patents

Abstract

PURPOSE:To adjust the intermitted time of operation of a windshield wiper depending on the quantity of raindrops to enable accurate operation, by converting the output of a raindrop detecting piezoelectric element into digital signals, counting the signals and driving the wiper with the intermitted time depending on the counted value. CONSTITUTION:A piezoelectric element 1 converts raindrop vibration into an electric signal, which is applied to a shaping circuit 6 to shape the wave form of the signal to send out a pulse signal. Such pulse signals are applied to a counter circuit 7 so that the pulse signals are counted. When the counted number has reached a prescribed value, a pulse signal is sent out to a wiper drive circuit 5 to operate a windshield wiper. According to this constitution, even if the output of the piezoelectric element 1 fluctuates minutely, the output timing of the pulse signal from the counter circuit 7 is not adversely affected, so that the intermitted time of operation of the wiper is controlled to be appropriate depending on the quantity of raindrops.

Description

DETAILED DESCRIPTION OF THE INVENTION ``Misfire'' relates to an intermittent wiper system rMK for a vehicle that conveniently controls the intermittent timing of the wiper according to the presence of raindrops.

Most vehicle wipers can operate at two speeds, low and high, by operating a switch lever. In addition, in light rain or rain, the wipers operate once, then stop for 5 seconds and then restart again. 6 It is possible to cause the so-called...J non-operation. Recently I used the wiper like this t14
” Missing crop! A method has been proposed in which the intermittent time is controlled according to the amount of raindrops hitting the windshield.

Figure 1 shows an example of a block diagram of Yuzu's conventional intermittent wiper device, in which 1 is made of barium titanate or Rochelle salt crystals that detect vibrations caused by raindrops, and is installed on the cowl top panel. This is a piezoelectric element that detects vibrations caused by raindrops colliding with a shaken iIJ plate. When the piezoelectric element 1 converts the vibration of the diaphragm into an electrical signal, that signal is amplified by an amplifier circuit 2.

Thereafter, the output signal from the amplifier circuit 2 is processed in a smoothing circuit 3 according to charging characteristics according to the size of the raindrops, and is output as a smoothed signal that changes in an analog manner. In the comparison circuit 4, this analog signal is compared with the reference value, and as a result, a pulse signal is outputted from the comparison circuit 4. The wiper and wiper (not shown) are operated manually in step 5, but this pulse signal is output at time intervals according to the amount of raindrops, so the intermittent time of the wiper is controlled according to the amount of raindrops. .

By the way, in an intermittent wiper device, there is a relay that turns on and off the wiper drive circuit constantly in response to the output of the wiper amplifier that outputs the intermittent drive signal. Because the operating noise is noisy, the wiper device components are usually installed on the instrument panel side in the engine room, or if only the relay is installed in the engine room, it will be difficult to assemble. The circuit section is also installed inside the engine room. However, the temperature in the engine room does not rise because of the heat generated by the engine6, which may change the capacitor size of the smoothing circuit 3 or cause leakage current, which may change the charging characteristics. . Therefore, in the above wiper device, the intermittent time is not controlled by the ablog signal.
The wiper intermittent time may not be constant due to temperature changes,
l? If JJ is out for a long time, there is a problem in that raindrops will accumulate on the front windshield and obstruct the forward view.

In this way, the method of comparing the absolute log signal with the threshold value may cause an error in the adjustment of the wiper drive signal, so it is necessary to adjust the intermittent time by turning on and off the switching element. The focus is on what can and cannot be done.

The present invention was developed in view of the above points, and in order to reliably control the wiper intermittence depending on the amount of raindrops, the output of the pressure element for detecting raindrops is digitally converted and counted. However, the wiper is driven at an intermittent time according to the =lrb value.

The present invention will be explained below based on the drawings.

FIG. 2 is a block diagram showing an embodiment of the intermittent wiper device according to the present invention, in which a waveform shaping circuit 6 and a counter circuit 7 are provided between the piezoelectric element 1 and the wiper drive circuit 5.

The vibration of the raindrops is transmitted to the waveform shaping circuit 6 by the piezoelectric element 1, and the waveform shaping circuit 6 outputs the waveform as a pulse signal. When the counter circuit 7 is manually inputted, the number of pulse signals is counted, and when the count value reaches a predetermined value, the pulse signal is outputted.As a result, this pulse signal is manually input to the wiper drive circuit 5. The output timing (this pulse signal) determines whether the wiper is activated or not, even if there is a slight change in the output of the piezoelectric element due to a rise in temperature in the engine compartment or fluctuations in the element. The wiper's intermittent time is controlled at exactly the same time as the raindrops, and there is no risk of the forward visibility being obstructed by the raindrops. 0 FIG. 3 is a block diagram showing another embodiment of the intermittent wiper device according to the present invention, in which the same reference numerals as in FIG. 2 indicate the same components. In this embodiment, an oscillation circuit 8 is provided which outputs a pulse signal at intervals of one peak at a predetermined time, and the counter circuit 7 converts the pulse signal output from the oscillation circuit 8 into the pulse signal output from the waveform shaping circuit 6. When the counted value reaches a predetermined value, the pulse signal is output. When this pulse signal is manually applied to the wiper drive circuit 5, the wiper operates, but the output timing of this pulse signal' may vary depending on the temperature rise in the engine compartment and the vibrancy of the element, as in the first embodiment. Even if a slight change occurs in the output of the wiper, the output a is output at a time interval corresponding to the amount of raindrops VC without being affected by the change, so the wiper intermittent time is controlled according to the amount of raindrops i, and the raindrops cause the There is no risk that your vision will be obstructed.

Furthermore, in this embodiment, even when vibrations of raindrops are not detected by the piezoelectric element 1, such as when the raindrops are not passing through a tunnel, the output of the oscillation circuit 8 is transmitted to the counter circuit 7.
Since it is counted by 1, the outage is longer, but the wipers can be operated and the windshield is not left with raindrops on the front windshield. There is no risk of interference.

By the way, ' I (Is the raindrop of li!i1 wide when it hits the flat plate?) 00-Ani Atoka Wei: From what I didn't introduce, the area of the diaphragm of the piezoelectric element is 100- or more. It is preferable to use the diaphragm Uij or 1: OO
yxA or less, one flZ using multiple pressure sensitive elements
If it does not constitute a tug, the total effective number of diaphragms is 1IIJ.
It is better to make me 100- or more.

In this embodiment, the wiper intermittent time is controlled depending on the amount of raindrops, or the wiper is manufactured at a low speed or local speed. It can also be used for control of 1C when activated in the case of II and B.

As explained above, according to the present invention, the output of the pressure element for raindrop detection is digitally converted and counted, and Mi'Ib
Since the wiper is driven at an intermittent time according to the value, there is no variation in the wiper operating time m due to element characteristics or lagooning, so there is no fear that raindrops will obstruct the forward view. Also, if it is shifted as in the embodiment shown in Fig. 3,
Even when you are not passing through a tunnel, raindrops will not remain on the windshield, and there is no risk of obstructing the view ahead.

[Brief explanation of the drawing]

Fig. 1 is an example of a block diagram of a conventional intermittent wiper assembly, Fig. 2 is a block diagram showing an embodiment of an intermittent wiper device according to the present invention, and Fig. 3 is a block diagram showing an example of an intermittent wiper assembly according to the present invention. FIG. 3 is a block diagram showing another embodiment of the missing wiper device. Engineering: piezoelectric element, 2: amplifier circuit, 3: smoothing circuit, 4: comparison circuit, 5: wiper drive circuit, 6:
...Waveform shaping circuit, 7...Counter circuit, 8...Oscillation circuit Patent applicant: Hiroo Meki, Patent Attorney, Nissan Motor Co., Ltd.

Claims (2)

[Claims] (1) A piezoelectric element that detects vibrations caused by raindrops colliding with a diaphragm installed on a diaphragm installed on a vehicle body panel, a conversion means that converts the output of the piezoelectric element into a digital signal, and a digital conversion means that converts the output of the piezoelectric element into a digital signal. An intermittent wiper device for a vehicle, characterized in that the wiper is not driven at an intermittent time when the I/BJ force is measured. (2) The intermittent wiper device according to claim 1, wherein the & moving plate has an area of 100 d or more.