JPH04143150A - Wiper device - Google Patents

Abstract

PURPOSE:To secure the excellent field of view even when it lightly rains and drizzles, and thereby secure the safety of running by controlling a wiper motor in rotation in response to the current value of the wiper motor even when it lightly rains and drizzles where a rain-drop sensor does not work at all. CONSTITUTION:A wiper is driven by a wiper motor A. The value of current flowing to the wiper motor A is detected by a motor current detecting sensor B. Furthermore, the amount of rain drops is detected, so that the detected signal is outputted from a rain-drop sensor C. And the wiper motor A is operated when the detected signal is outputted from the rain drop sensor C, even in the case that no detected signal is outputted from the rain drop sensor C, when current from the motor current detecting sensor B is less than a reference current value, it is judged that it lightly rains and drizzles, so that the wiper motor A is controlled by a control device D to be concurrently operated. By this constitution, the wiper motor is surely operated even when it lightly rains and drizzles, and the field of view can thereby excellently secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a wiper device that can operate a wiper according to conditions outside a vehicle.

(Prior Art) As a conventional wiper device, there is, for example, one shown in FIG. 4 (Japanese Unexamined Patent Publication No. 140146/1983).

When the control bag W1 detects that the wiper intermittent (INT) switch 3 is turned on, the control bag W1 receives a detection signal from a raindrop sensor 5 composed of, for example, a vibration sensor, and controls the rotation speed of the wiper motor 7 according to the detection signal. do. Here, the #J control device 11 is composed of, for example, a microcomputer device and its peripheral circuits, and has a timer inside the microcomputer device.

In the control bag W1 of such a wiper device, the process shown in the flowchart of FIG. 5 is executed. That is,
When the switch 3 is on, the control device 1 first resets the timer t (t-0) (steps 100 and 10).
1).

Next, the control device 1 checks the detection signal from the raindrop sensor 5, and when there is a detection signal from the raindrop sensor 5 (step 102 YES), it assumes that it is raining outside the vehicle and turns on the wiper motor 7 on the condition that the switch 3 is turned on. Rotate only once (steps 103 and 104).

Next, the control device 1 resets the timer t (step 1
05) L, return to step 102 again and move to the starting point of the above operation.

Furthermore, when the control device 1 examines the detection signal from the raindrop sensor 5 and there is no detection signal from the raindrop sensor 5 (step 102 NO), the control device 1 determines the value of the timer t on the condition that the switch 3 is turned on (step III YES). The controller waits until the timer t reaches the reference time value to, and when the value of the timer t reaches the reference time value to, the wiper motor 7 is rotated only once (step 113).

In this manner, the conventional wiper device senses the amount of raindrops using the raindrop sensor 5 and controls the wiper intermittent time.

(Problem to be Solved by the Invention) However, in the conventional wiper device, the raindrop sensor 5 may not respond in the case of light rain or drizzle, so the control device 1 Loop with no detection signal (steps 102, 111, 1
12,113). Therefore, there is a problem in that the wiper does not operate until the fixed intermittent time (reference time value) is reached.

The wiper device of the present invention has been developed by focusing on these conventional problems, and solves the above problems by making it possible to operate the wiper reliably even in conditions such as light rain or drizzle. It aims to solve the problem.

[Structure of the invention]

(Means for Solving the Problem) In order to achieve the above object, the wiper device of the present invention has the following features:
As shown in FIG. 6, there is a wiper motor A that drives the wiper, a motor current detection sensor B that detects the current value flowing through the wiper motor A, and a raindrop sensor C that detects the amount of raindrops and outputs a detection signal. The wiper motor A is operated when there is a detection signal from the raindrop sensor C, and the current from the motor current detection sensor B is smaller than a reference current value even when there is no detection signal from the raindrop sensor C. The wiper motor A is also provided with a control device that operates the wiper motor A upon determining that it is raining lightly or drizzling rain.

(Operation) This invention focuses on the fact that the current of the wiper motor reflects the state of adhesion of water droplets on the glass surface, and even when there is no detection signal from the raindrop sensor, the current of the wiper motor is larger than the reference current value. The operation of the wiper motor is controlled depending on whether it is small or small.

This ensures good visibility even in light rain or drizzle.

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

First, the relationship between the state of adhesion of water droplets on the glass surface and the current of the wiper motor will be explained using FIG. 3.

FIG. 3 shows the relationship between the wiper motor current i (vertical axis) and the amount of rain that adheres to the glass (horizontal axis). Further, in FIG. 3, there are a completely dry state PPD, a semi-dry state PSD, and a completely wet state PWT based on the current value IO, and the current value i of the wiper motor changes according to each state as shown. Completely dry PPD
is in the wiper unnecessary area Wa and is semi-dry! ! P.S.D.
is in the region wb in which the raindrop sensor is difficult to operate, and the completely wet state apwT is in the operating region Wc of the raindrop sensor.

In this invention, when the current value i of the wiper motor is in the region wby where the current value i of the wiper motor is smaller than the current value IO out of the region wb in which the raindrop sensor is difficult to operate, the wiper motor is determined to be in a light rain or drizzle state and the wiper motor is controlled. It is something. below,
The configuration of this invention will be specifically explained.

FIG. 1 is a block diagram showing an embodiment of a wiper device of the present invention.

The wiper device shown in FIG. 1 includes a control device 11, an auto switch 13, a raindrop sensor 15, a wiper motor 17, and a motor current detection sensor 19.

The control device 11, when the auto switch 13 is on,
The rotation of the wiper motor 17 is controlled according to detection signals from the raindrop sensor 15 and the motor current detection sensor 19. The on/off signal of the auto switch 13 is input to the arithmetic processing section 22 via the input interface circuit 21 of the microcomputer device 20 of the control device 11 .

Although not shown, this arithmetic processing unit 22 includes an RO which stores a processing program, reference time values tl, t2, and reference current value ■.
M, a RAM for storing predetermined data, etc., and a timer. The calculation results and processing outputs of the calculation processing section 22 are supplied to the motor drive circuit 24 via the output interface circuit 23.

The motor drive circuit 24 controls the rotational drive of the wiper motor 17 according to the applied control signal S1. The electric circuit of the wiper motor 17 includes a motor current detection sensor 1.
9 are connected in series, and the detection signal thereof is input to the signal preprocessing circuit 25, converted into a digital signal, and then supplied to the arithmetic processing section 22 via the input interface circuit 21.

Furthermore, the detection signal from the raindrop sensor 15 is processed by a signal preprocessing circuit 26 and supplied to the arithmetic processing section 22 via the input interface circuit 21 .

Next, the operation of this embodiment will be explained with reference to the flow chart of FIG.

The flowchart in FIG. 2 is executed by the arithmetic processing unit 22 of the control device 11, and is started by a wiper operation start command.

When the auto switch 13 is turned on (step 200
), first, the wiper motor 17 is operated only once (step 201). At this time, the arithmetic processing unit 22 of the control device 11 takes in the motor current detection signal from the motor current detection sensor 19 through the signal preprocessing circuit 25 and the input interface circuit 21 and stores it (step 202).

Suppose now that the PWT is in a completely wet state as shown in Fig. 3.
Assume that the raindrop sensor 15 is in the operating range We. At this time, the detection signal from the raindrop sensor 15 is manually input to the arithmetic processing unit 22 through the signal preprocessing circuit 26 and input interface circuit 21 (step 203).
On the condition that the auto switch 13 is on (step 204 YES), the arithmetic processing unit 22 returns to step 201 to rotate the wiper motor 17 only once again. Hereinafter, the arithmetic processing unit 22 of the control device f11 performs step 201 when the raindrop sensor 15 is in the operating region Wc.
Repeat the operations from to 204.

On the other hand, when the raindrop sensor 15 is in the region wb where it is difficult to operate in the semi-dry state PSD, the arithmetic processing unit 22 of the control device 11 cannot detect the detection signal from the raindrop sensor 15 (step 203 NO), so the arithmetic processing unit 22 First, reset the timer t (step 205)
, then the detected current i from the motor current detection sensor 19
and the reference current value IO (step 206).

At this time, if the detected current i is smaller than the reference current value 10 (step 208 NO), the area W b in FIG.
y, the arithmetic processing unit 22 selects the auto switch 1.
3 is on and there is no detection signal from the raindrop sensor 15 (step 207.20g), the timer t is compared with a first reference time value tl (tl<t2° approximately 10 seconds) (step 209). Here, if the timer t has not reached the first reference time value tl (step 209
NO), the arithmetic processing unit 22 repeatedly executes steps 207 to 209. The timer t is the first reference time value t1
When it reaches (step 209 YES), the arithmetic processing unit 2
Step 2 is to operate the wiper motor 17 once.
Return to 1. That is, in the case of this region wby, the wiper motor 17 is rotated at intervals of time (tl) shorter than the normal fixed intermittent time (t2.about.20 seconds). In addition,
When the arithmetic processing unit 22 receives a detection signal from the raindrop sensor 15 during the processing in steps 207 to 209, it immediately shifts to the completely wet state PWT operation shown in steps 201 to 204.

In addition, wiper unnecessary area Wa with completely dry flPPD
, and when the raindrop sensor 15 is in the region wb where it is difficult to operate, the arithmetic processing unit 22 of the control device [11 cannot detect the detection signal from the raindrop sensor 15 (step 2).
03), the arithmetic processing unit 22 first resets the timer t (step 205). Next, the detected current i from the motor current detection sensor 19 is compared with a reference current value 0 (step 20B).

In this case, since the detected current i is in the area Wa and the area Wbx in FIG. On the condition that there is no detection signal (steps 210 and 211), the timer t is compared with a second reference time value t2 (t2>tl) (step 213). Here, if the timer t has not reached the second reference time value t2, the arithmetic processing unit 22 repeatedly executes steps 210 to 212. Timer t reaches second reference time value t2 (step 213)
Then, the arithmetic processing unit 22 returns to step 201 in which the wiper motor 17 is operated once.

That is, in the case of the region Wa and the region Wbx, the wiper motor 17 is rotated at regular fixed intermittent time intervals (t2). Note that when the arithmetic processing unit 22 receives a detection signal from the raindrop sensor 15 during the processing of steps 210 to 212, it immediately shifts to the operation of the completely wet state PWT shown in steps 201 to 204.

As explained above, in this embodiment, the rotational operation of the wiper motor 17 is controlled according to three areas.
Even if the raindrop sensor 15 does not work in conditions such as light rain or drizzle, the wiper operates reliably and the driver's forward visibility can be secured.

〔Effect of the invention〕

As explained above, according to the present invention, the configuration is such that the rotational operation of the wiper motor is controlled according to the current value of the wiper motor even in light rain or drizzle conditions where the raindrop sensor does not work. Therefore, it is possible to secure visibility even in light rain or drizzle, and to ensure safe operation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of a wiper device according to the present invention, Fig. 2 is a flowchart for explaining the operation of the same embodiment, and Fig. 3 shows the relationship between the amount of moisture adhered to the glass and the wiper motor current. FIG. 4 is a block diagram showing the conventional device, FIG. 5 is a flowchart for explaining the operation of the conventional device, and FIG. 6 is a diagram corresponding to the claims of the present invention. DESCRIPTION OF SYMBOLS 11... Control device, 13... Auto switch, 15... Raindrop sensor 17... Wiper motor, 19... Motor current detection sensor 20... Microcomputer device, 21... Input interface circuit , 22... Arithmetic processing unit, 23... Output interface circuit. Agent Patent Attorney Hidekazu Miyoshi I3 Figure I4 Figure 5

Claims (1)

[Scope of Claims] A wiper motor that drives a wiper, a motor current detection sensor that detects the value of current flowing through the wiper motor, a raindrop sensor that detects the amount of raindrops and outputs a detection signal, and from the raindrop sensor. The wiper motor is operated when there is a detection signal, and even if there is no detection signal from the raindrop sensor, if the current from the motor current detection sensor is smaller than a reference current value, it is determined that it is a light rain or drizzle state. A wiper device comprising: a control device for operating the wiper motor.