JPS6346953A - Automatic driving gear for wiper - Google Patents

Abstract

PURPOSE:To prevent a wiper from its unnecessary or unnatural action, by controlling an integrated value so as to be reset when it increases not exceeding a threshold value even after the fixed time from a start of integrating raindrop pulses. CONSTITUTION:An electronic control unit 10 uses a microcomputer which performs integration of raindrop pulses, comparison of the integrated value, counting of the integrated time, resetting by the time over, etc., and the electronic control unit 10 controls the integrated value so as to be reset when it increases not exceeding a threshold value even after the fixed time from a start of integrating the raindrop pulses from a raindrop sensor 1. In this way, if a time limit is given to the integrating action of the raindrop pulses, the integrated value, before it reaches the threshold value, is reset when a rainfall is in a small amount, and the integrated value is reset in every fixed time. Accordingly, a wiper can be prevented from performing its unnecessary or unnatural action.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a raindrop sensing type automatic wiper drive device, and is particularly intended to impose a time limit on the accumulation operation of raindrop pulses.

[Conventional technology]

As shown in FIG. 4, a conventional raindrop sensing type automatic wiper drive device integrates raindrop pulses from a raindrop sensor 1 in an integrating circuit 2, and compares the integrated value with a predetermined threshold value in a comparator circuit 3. In many cases, when the integrated value exceeds a threshold value, the relay 4 is turned on and the wiper motor 5 is operated. Although the mechanical part of the wiper is not shown, when the wiper moves back and forth once due to the rotation of the motor 5, an operation completion detection switch called a cam switch resets the integrating circuit 2 (RST), and the output of the comparator circuit 3 is inverted. Relay 4 turns off. Since the integrating circuit 2 restarts the integrating operation from this point, the operating waveforms of each part become as shown in FIG. In other words, the wiper operation cycle is from one RST to the next RST, and this becomes shorter as the amount of rain increases.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned method, since the value in the middle of integration is always held, the wiper operates even if the integrated value exceeds the threshold value over a long period of time (for example, one minute or more). Further, even if noise is integrated, malfunctions occur.

However, in such a case, since the amount of rain is small, the wiper not only operates unnaturally, but also wipes the dry windshield, causing damage to the wiper blade.

The present invention attempts to eliminate the above-mentioned drawbacks by placing a time limit on the raindrop pulse accumulation operation.

[Means for solving problems]

The present invention provides an automatic wiper drive device that integrates raindrop pulses from a raindrop sensor, and each time the integrated value exceeds a predetermined threshold, the wiper is moved back and forth once and the integrated value is reset. The present invention is characterized in that the integrated value is controlled to be reset when the settled value does not exceed the threshold even after a certain period of time has elapsed since the start of the integrated value.

[Effect]

If a time limit is placed on the raindrop pulse accumulation operation, when the amount of rainfall is small, the accumulated value will be reset before it reaches the threshold value, and unnecessary wiper operations can be avoided.

[Embodiment] Fig. 1 is a block diagram showing an embodiment of the present invention, in which lO is an electronic controller using a microcomputer that integrates raindrop pulses, compares the integrated values, counts the integrated time, and sets the value when the time is over. Control unit (ECU), 2
0 is a wiper device including a wiper motor, a cam switch, a wiper blade, etc.

FIG. 3 is a flowchart of wiper control by the ECUIO, in which processing corresponding to the integrating circuit 2 and comparing circuit 3 in FIG. 4 is performed by software. Also, a timer that counts the accumulated time is realized by a software counter or the like.

Then, when the integrated value exceeds the threshold value, R3
Apart from T, a reset RST' is also performed when the cumulative time exceeds a certain value T. In the former case, the process moves to wiper operation processing, but in the latter case, the process enters a waiting loop in order to avoid repeating the reset R3T' unnecessarily.

FIG. 2 is an operational waveform diagram, in which reset R3T due to exceeding the threshold value, reset R8T' due to time over, and reset R3T due to exceeding the threshold value are shown in order. The value of the fixed time T is set to, for example, 60 seconds.

Note that the taillight signal input to the ECUIO is used to change the threshold value between night and daytime, and the vehicle speed signal is used to change the threshold value depending on the speed. The present invention can also be applied to an analog circuit as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, since the integrated value is reset at regular intervals, unnecessary or unnatural wiper operations can be prevented.

[Brief explanation of drawings]

1 to 3 are block diagrams showing an embodiment of the present invention,
Operation Waveform Diagram and Flow Chart FIGS. 4 and 5 are block diagrams and operation waveform diagrams of a conventional automatic wiper drive device. In the figure, 1 is a raindrop sensor, 2 is an integration circuit, 3 is a comparison circuit,
10 is an electronic control unit, and 20 is a wiper device. Applicant: Fujitsu Ten Ltd. Applicant: Patent attorney representing Toyota Motor Corporation 2 times unreleased [111n flowchart 12 禾's Moyo Fiba has been neglected! Fig. 4 Isami O'#n drawing of the wave shape

Claims (1)

[Claims] In an automatic wiper drive device that integrates raindrop pulses from a raindrop sensor and moves the wiper back and forth once every time the integrated value exceeds a predetermined threshold value and resets the integrated value, the integrated value is constant from the start of the integration of the raindrop pulses. An automatic wiper drive device characterized by controlling the integrated value to be reset when the integrated value does not exceed the threshold value even after a period of time has elapsed.