JPH07121681B2 - Wiper control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wiper control device that drives a wiper blade at a wiping interval suitable for rainfall.

2. Description of the Related Art Problems to be Solved by the Related Art and Invention Raindrops adhere to the windshield of an automobile, and the timing at which the driver wants to operate the wiper varies depending on the size of the raindrops, the amount of rain, or the vehicle speed. In particular, drizzle and raindrops splashed up by a preceding vehicle or the like have a very small diameter, and therefore, if they adhere to the windshield, they will not easily flow down, and even if the amount of rain is small, it will hinder the visibility. Further, in general, the sensitivity of the raindrop sensor increases as the raindrop diameter increases.

However, in a typical prior art wiper controller,
When the integrated value obtained by integrating the outputs from the raindrop sensor exceeds a predetermined threshold value, the wiper blade is driven. Therefore, regardless of the raindrop diameter, the wiper blade is not driven until the integrated value exceeds the threshold value. For this reason, it becomes difficult to secure the driver's field of view, and the wiping interval desired by the driver deviates from the actual wiping interval of the wiper blade, which causes discomfort.

An object of the present invention is to provide a wiper control device that can drive a wiper blade at a wiping interval suitable for rainfall conditions.

Means for Solving the Problem The present invention is, in a wiper control device for driving a wiper blade, when an integrated value obtained by integrating outputs corresponding to raindrop diameters from a raindrop sensor is a predetermined threshold value or more, an output from the raindrop sensor. Comparing means for comparing with a predetermined discrimination value, when the output from the raindrop sensor is equal to or more than the discrimination value, the output value of the raindrop sensor is integrated, and the wiper blade is driven when the integrated value is equal to or more than the threshold value. When the output from the raindrop sensor is less than the discrimination value, the number of outputs from the raindrop sensor is integrated, and the integrated value is equal to or greater than a threshold value that is different from the threshold value. Then, the wiper control device is provided with a second drive means for driving the wiper blade.

Operation According to the present invention, when the wiper blade is driven when the integrated value obtained by integrating the outputs from the raindrop sensor becomes equal to or greater than the predetermined threshold value, the output from the raindrop sensor is compared with the predetermined discrimination value in the comparison means. If the output from the raindrop sensor is equal to or more than the discrimination value based on the comparison result, and the integrated value obtained by integrating the output values of the raindrop sensor is equal to or more than the threshold value by the first driving means, When the blade is driven and the output from the raindrop sensor is less than the discrimination value, the second drive means provides an integrated value obtained by integrating the number of outputs from the raindrop sensor different from the threshold value. When it is equal to or more than the threshold value of, the wiper blade is driven.

That is, when the output from the raindrop sensor is equal to or more than the discrimination value, the output is integrated, and when the output is less than the discrimination value, the number of outputs, that is, the number of output pulses is integrated and compared with a threshold value provided individually. It is determined whether or not the wiper blade should be driven. This also allows the wiper blade to be driven at an optimum wiping interval suitable for rainfall conditions.

First Embodiment FIG. 1 is a block diagram showing an electrical configuration of a wiper control device 30 showing a configuration on which the present invention is based. The wiper control device 30 is a so-called automatic wiper control device that controls the wiping interval of the wiper blade based on the integrated value of the output of the raindrop sensor 1.

The raindrop sensor 1 is composed of, for example, a pair of light emitting / receiving elements, and raindrops can be detected by blocking the optical path between the light emitting / receiving elements. Each time a raindrop passes, an output having a crest value and a convergence time corresponding to the raindrop diameter is derived from the raindrop sensor 1 every time a raindrop passes, and the waveform shaping circuit of the wiper control circuit 2 is derived.
Input to 3a. The waveform shaping circuit 3a discriminates the output from the raindrop sensor 1 shown in FIG. 2 (1) at a predetermined discrimination level l1, and the period t during which the output from the raindrop sensor 1 is equal to or higher than the discrimination level l1. Only, a low-level detection signal is derived as shown in FIG. 2 (2) and given to the processing circuit 4 realized by a microcomputer or the like.

An automatic wiper switch 5 is provided in association with the wiper control circuit 2. When the automatic wiper switch 5 is brought into a conducting state, an automatic wiper operation as described later is realized. In the waveform shaping circuit 3b, noise components such as so-called chattering are removed from the output of the auto wiper switch 5, and the output is input to the processing circuit 4 as a wiper switch signal.

The processing circuit 4 sets the operating state of the wiper in response to the detection signal from the raindrop sensor 1 and the wiper switch signal from the automatic wiper switch 5. That is, when the amount of rainfall is small, the wiper is brought into an intermittent operation state, the intermittent time is shortened as the amount of rainfall increases, and when the amount of rainfall exceeds a predetermined value, the wiper is set to a low speed continuous operation state. When the amount of rainfall further increases and exceeds a predetermined value, the high speed continuous operation state is set.

When the operating state is set in this way, the processing circuit 4 derives a high level wiper drive signal from the output terminal P1 during low speed operation and derives the wiper drive signal from the output terminal P2 during high speed operation. The wiper drive signal from the output terminal P1 is given to the base of the switching element 7 via the resistor 6 and the bias resistor 8. The collector of the switching element 7 is connected via a relay coil 11 of a relay 10 to a battery 9 mounted on the vehicle, and the emitter is grounded. When the switching element 7 is turned on, the relay coil 11 is excited and the relay switch S1 is turned on to one of the individual contacts S1b. This relay switch S1
The individual contact S1b is connected to the battery 9, and the common contact S1a is connected to the low speed operation input terminal 12a of the wiper motor 12. The wiper motor 12 is, for example, a DC motor, and the common terminal 12c is grounded.

A cam switch S2 interlocking with the wiper motor 12 is provided in association with the wiper motor 12.
One individual contact S2c of S2 is connected to the battery 9,
The other individual contact S2b is connected to the common terminal 12c of the wiper motor 12, and the common contact S2a is connected from the line pl1 to the other individual contact S1c of the relay switch S1 via the switch S4.

The cam switch S2 conducts to the individual contact S2b when the wiper motor 12 has a rotation angle of 0 to 30 °, and when the rotation angle is more than 30 ° and less than 360 °, the individual contact S2b.
Conducts to 2c. Switch S4 is a relay switch described later.
Opening / closing control is performed in conjunction with S3, and the switch S4 is cut off when a high speed wiper operation is performed, and is conductive when a low speed wiper operation is performed. The potential of the common contact S2a of the cam switch S2 is input to the processing circuit 4 from the line sl1 via the waveform shaping circuit 3c. When the line sl1 goes high, the processing circuit 4 stops deriving the wiper drive signal from the output terminals P1 and P2.

Therefore, when the wiper drive signal is derived from the output terminal P1 as described above, the switching element 7 becomes conductive, the relay coil 11 is excited, and the relay switch S1 becomes the individual contact S1b.
Conduct to. In this way, when the wiper motor 12 is activated and its rotation angle exceeds 30 °, the cam switch S2 is conducted to the individual contact S2c. As a result, the line sl1 goes high, and the processing circuit 4 stops sending the wiper drive signal. When the transmission of the wiper drive signal is stopped, the switching element 7 is cut off, the relay coil 11 is demagnetized, and the relay switch S1 is electrically connected to the individual contact S1c.

Therefore, the power from the battery 9 is transferred from the contacts S2c and S2a of the cam switch S2 to the relay switch S4 via the switch S4.
The wiper motor 12 is continuously supplied from the first contact S1c, S1a. When the wiper motor 12 is driven 360 °, that is, one rotation, the cam switch S2 is electrically connected to the individual contact S2b and the drive of the wiper motor 12 is stopped. In this way, when the wiper blade reaches the predetermined storage position without stopping in the middle position of the wiping operation, the wiper motor
12 drive is stopped.

The wiper drive signal derived from the output terminal P2 of the processing circuit 4 is given to the base of the switching element 21 via the resistor 20 and the bias resistor 22. Switching element
The collector of 21 is connected to the battery 9 via the relay coil 24 of the relay 23, and the emitter is grounded.

When the switching element 21 becomes conductive and the relay coil 24 is excited, the relay switch S3 becomes conductive, and the power from the battery 9 is supplied to the high speed operation input terminal 12b of the wiper motor 12 through the relay switch S3. It At this time, the switch S4 is cut off in synchronization with the relay switch S3, and thus the wiper motor 12 is driven at high speed.

A constant voltage circuit 25 is also provided in association with the wiper control circuit 2, and electric power from the battery 9 is supplied to each circuit in the wiper control circuit 2 via the constant voltage circuit 25.

In the wiper control device 30 configured as described above, the sensitivity of the raindrop sensor 1 is shown in FIG. 3, and when the raindrop diameter is smaller than a predetermined value l2, the sensor sensitivity sharply decreases as the raindrop diameter decreases. However, when the value is equal to or more than the predetermined value l2, it is possible to obtain the sensor sensitivity substantially corresponding to the raindrop diameter.

The processing circuit 4 integrates the period t in which the detection signal shown in FIG. 2 (2) is derived, and derives the wiper drive signal when the integrated value exceeds a predetermined threshold value. At this time, the processing circuit 4 changes the threshold depending on whether or not the period t in which the detection signal shown in FIG. 2 (2) is derived is equal to or longer than the period T which is a predetermined discrimination value. That is, when the raindrop diameter is large and the output from the raindrop sensor 1 is large as shown by the solid line in FIG. 2 (1), the period t during which this output exceeds the discrimination level l1 becomes long. On the other hand, when the raindrop diameter is small such as drizzle and the output from the raindrop sensor 1 is small as shown by a virtual line in FIG. 2A, this period t becomes short.

However, as described above, when the diameter of the raindrop becomes smaller than a certain level, the driver feels a delay in the wiping operation corresponding to the rainfall amount, and it becomes difficult to secure the visibility.
Therefore, in the present configuration, when the period t is less than the predetermined period T, and the integrated value Σta of the period t becomes equal to or larger than the first threshold t1 set in advance, the wiper blade wiping operation is performed. Further, the period t of the detection signal is a predetermined period T
When the above is the case, the wiping operation of the wiper blade is performed at the time when the integrated value Σtb of the period t becomes equal to or more than the threshold value t2 which is larger than the predetermined first threshold value t1.

FIG. 4 is a flow chart for explaining the operation. In step n1, it is judged whether or not the detection signal is derived from the raindrop sensor 1, that is, whether or not it is in a raining state. If not, this step n1 is repeated, and when the detection signal is derived, the process proceeds to step n2. In step n2, it is judged whether or not the period t in which the detection signal is derived is longer than or equal to the predetermined period T. If not, that is, when the raindrop diameter is small, the process proceeds to step n3. In step n3, the integrated value Σta of the period t is calculated, and in step n4, the integrated value Σta is determined in advance.
It is determined whether or not the threshold value t1 is equal to or more than the threshold value t1 of the above, and if not, the process returns to the step n1, and if so, the process proceeds to step n5.

In step n2, when the period t of the detection signal is equal to or longer than the predetermined period T, the process proceeds to step n6, the integrated value Σtb of the period t is calculated, and the process proceeds to step n7. At step n7, the second threshold value t2 which is predetermined by the integrated value Σtb is set.
It is determined whether or not the above is the case, and if not, the process returns to the step n1, and if so, the process moves to step n5.

In step n5, the integrated values Σta and Σtb are reset, and in step n8, the wiper blade wiping operation is performed and the process returns to step n1.

FIG. 5 is a flow chart for explaining the operation of one embodiment of the present invention. This embodiment is similar to the configuration shown in FIG. 4 described above, and the same reference numerals are given to corresponding parts. . In this embodiment, when the period t of the effect signal in step n2 is less than the predetermined period T, step n3
Moving to a, the number of raindrops detected by the raindrop sensor 1, that is, the integrated value Σnta of the number of raindrops is obtained regardless of the raindrop diameter. In step n4a, it is judged whether or not the integrated value .SIGMA.nta is equal to or more than a predetermined value N, and if not, the process returns to step n1 and if so, step n5
Move to a. At step n5a, the integrated values Σnta and Σtb are reset, and the routine goes to step n8.

EFFECTS OF THE INVENTION According to the present invention, based on the result detected by the comparison means, when the raindrop diameter is equal to or larger than a predetermined value, outputs of the raindrop sensor are integrated as they are, and when the integrated value becomes equal to or larger than a threshold value, the wiper plate is set If it is driven, and the raindrop diameter is less than a predetermined value, the output count of the raindrop sensor is integrated, and the integrated value is configured to drive the wiper plate when it becomes equal to or more than another threshold value different from the threshold value. Even if the diameter of raindrops such as drizzle or splashed raindrops is small and the integrated value is small, the wiper blade is driven at the optimum wiping interval suitable for the rain condition, and the driver's view is surely secured. In addition, it is possible to perform a light wiping operation that matches the driver's feeling.

[Brief description of drawings]

FIG. 1 is a wiper control device showing a configuration on which the present invention is based.
A block diagram showing an electrical configuration of 30, a waveform diagram of the output of the raindrop sensor 1 and a detection signal obtained by waveform-shaping the output, FIG. 3 is a graph showing the sensitivity characteristic of the raindrop sensor 1 with respect to the raindrop diameter, FIG. 4 is a flow chart for explaining the operation of the configuration shown in FIGS. 1 to 3, and FIG. 5 is a flow chart for explaining the operation of one embodiment of the present invention. 1 ... Raindrop sensor, 2 ... Wiper control circuit, 3a, 3b, 3c ...
... Waveform shaping circuit, 4 ... Processing circuit, 5 ... Auto power switch, 7,21 ... Switching element, 10,23 ... Relay, 30 ... Wiper control device, S1, S3 ... Relay switch, S2 ... … Cam switch, S4… switch

Claims (1)

[Claims] 1. A wiper control device for driving a wiper blade, when an integrated value obtained by integrating outputs corresponding to raindrop diameters from a raindrop sensor is equal to or larger than a predetermined threshold value. Comparing means for comparing, when the output from the raindrop sensor is equal to or more than the discrimination value, the output value of the raindrop sensor is integrated, and when the integrated value is equal to or more than the threshold value, a first driving means for driving the wiper blade; When the output from the raindrop sensor is less than the discrimination value, the number of outputs from the raindrop sensor is integrated, and the wiper blade is driven when the integrated value is equal to or more than another threshold value different from the threshold value. A wiper control device comprising: a second drive means.