JPS6341326B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wiper drive mode control device for selectively switching a vehicle wiper drive mode, for example, intermittent, low speed, and high speed modes.

Conventionally, the driver or the like manually operated a switch to select the wiper drive mode depending on the situation.

However, it is very cumbersome to operate the switch every time the amount of rainfall or vehicle speed changes, and the location of the changeover switch cannot be changed significantly, which limits the degree of freedom in outfitting the vehicle.

Therefore, a device has been proposed that can automatically select the wiper drive mode. According to this, for example, as shown in FIG. 1, the output of a sensor 1 that detects the impact force of raindrops as vibration is supplied to a bandpass filter 3 via an AC amplifier 2. The output of the bandpass filter 3 is supplied to the rectifier circuit 5 via the amplifier 4, and the output of the rectifier circuit 5 is supplied to the sensor 1.
If there is more than one, the adder 6 processes it. The output of this adder 6 is smoothed by a smoothing circuit 7 and compared with a predetermined set level by a comparator 8. In response to the output of the comparator 8, a wiper drive circuit 9 selectively operates to drive the wiper in, for example, intermittent, low speed, and high speed modes.

Further, as the sensor 1, for example, one shown in FIG. 2 was used. In the figure, reference numeral 10 denotes a receiving plate on which raindrops strike. One end of this receiving plate 10 is fixed to a support member 11, and this supporting member 11 is attached to a vehicle body 13 via a damper 12 made of an elastic member. Therefore, the damper 12 is provided to damp the high frequency component of vibration of the vehicle body 13, and the support member 11 is selected to have a small elastic coefficient and a large mass. Note that FIG. 3 shows the vibration characteristics of the sensor 1, and shows the so-called resonance frequency at the peak value of the vibration curve H of the support member 11.
₀ is determined by √k/m, and its vibration curve H is shifted to a lower frequency region than the vibration curve S of the vehicle body 13. Here, k is the elastic modulus and m is the mass. The receiving plate 10 also includes a supporting member 11 and a vehicle body 13.
In order to separate it from the vibration components (curves H and S), a material with a large elastic coefficient k and a small mass m is selected so that its resonance frequency number ₁ is kept away from ₀ .
Note that the vertical axis in FIG. 3 represents vibration acceleration.

FIG. 4 shows changes in the waveform of the signal obtained from the sensor 1 due to raindrops at each check point w, x, y, and z. The signal obtained by the sensor 1 is a signal Ls caused by the vibration of the vehicle body 13, and a vibration signal Lr corresponding to the impact force of raindrops, that is, the frequency of rain and the vehicle speed is superimposed (see FIG. 4a). When the signal from the sensor 1 is supplied to the bandpass filter 3, vibration components of the vehicle body 13 are removed (see FIG. 4b). The output of the rectifier circuit 5 is as shown in FIG. 4c, and the signal as shown in FIG. 4d is obtained by the smoothing circuit 7. The signal level v in FIG. 4d is proportional to the impact force of the raindrop.

However, such a conventional device has a sensor 1
Since the damper 12 is interposed in the sensor 1 and the signal from the sensor 1 is processed by the bandpass filter 3, the damper 12
It is necessary to appropriately select the frequency characteristics of the support plate 10, etc. to match the vibration characteristics of the vehicle body, and there is a drawback that only specified members can be used. Further, it is troublesome to select the frequency band of the bandpass filter 3 to match the frequency characteristics of the damper 12, etc. Furthermore, when the damper 12 is exposed to raindrops, it deteriorates over time and the frequency characteristics of absorption of high frequency components tend to change.

Note that there is also a conventional device configured to process the signal from the sensor 1 without the bandpass filter 3. According to this, a receiving plate 10 that resonates vibrations caused by raindrops in an ultrasonic region is provided, and this receiving plate 1
0, an ultrasonic vibration element made of, for example, ceramic is attached to generate a signal with a damped waveform corresponding to resonance.

However, even with such a conventional device, it is necessary to attach an ultrasonic absorbing member such as the damper 12 in order to absorb vibration components in the ultrasonic range caused by vibrations of the vehicle body 13. In addition, in order for the receiving plate 10 to resonate in the ultrasonic range, the mass must be made small, and therefore, raindrops accumulated on the receiving plate 10 cause a large change in the mass of the receiving plate 10, which in turn lowers the resonance frequency. becomes. In other words, stable operation could not be achieved.

This invention provides a damper between the vehicle body and the rainfall sensor, selects a damper material to attenuate the vehicle body vibration component, and filters the vehicle body vibration signal component on which the impact force vibration component is superimposed to a bandpass filter. To easily and reliably extract an impact force signal component based on an impact force without having to take the trouble of matching the frequency characteristics of a damper and its bandpass filter in order to remove the vehicle body vibration signal component through the vibration signal. An object of the present invention is to provide a wiper drive mode control device that can perform the following functions.

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

FIG. 5 to FIG. 9 are diagrams explaining embodiments of the present invention. First, to explain the configuration, reference numeral 20 in the figure is a rainfall sensor, and this rainfall sensor 20 is installed at a portion of the vehicle body 21 corresponding to the wiper wiper surface (not shown), and detects the impact force component generated by the impact force of raindrops. It detects the vehicle body vibration component generated by the vehicle body vibration and outputs a detection output in which the impact force signal component is superimposed on the vehicle body vibration signal component. Further, reference numeral 22 denotes a vehicle body vibration detection sensor, which is provided at a portion of the vehicle body that can detect a vehicle body vibration component equivalent to the vehicle body vibration component, and outputs only a vehicle body vibration signal component. Each sensor 20, 22
is connected to a differential amplifier 23 as a difference signal detector, and the differential amplifier 23 extracts an impact force signal component based on the impact force of raindrops based on the difference between the outputs of the respective sensors 20 and 22. The differential amplifier 23 is connected to a rectifier circuit 25 via an AC amplifier 24, and this rectifier circuit 25 is connected to the comparator 2 via a smoothing circuit 26.
7 is connected. This comparator 27 is connected to a wiper drive mode selection circuit 28 from which drive signals for various wiper drive modes are obtained depending on the magnitude of the output of the smoothing circuit 26, and a wiper motor M (not shown) for driving a wiper is connected to this circuit 28. ing.

The rainfall sensor 20 is, for example, shown in FIGS. 6a, b,
As shown in FIG. 6c, any of the piezoelectric method (FIG. 6a), photoelectric method (FIG. 6b), magnetoelectric method (FIG. 6c), etc. may be used. Rainfall sensor 20A using piezoelectric method
In this example, a substantially L-shaped support member 29 is attached to a portion of the vehicle body 21 corresponding to the wiper wiped surface, and one end of a receiving plate 30 is fixed to a rising portion of this support member 29. Strain gauges G, such as piezoelectric elements, are fixed to the upper and lower surfaces 30a and 30b of the receiving plate 30, for example. Of course, the receiving plate 30 is attached to catch raindrops.

The photoelectric rainfall sensor 20B includes a light emitting part ls and a light receiving part lr on the lower surface side of the receiving plate 30,
Vibration displacement caused by raindrops on the receiving plate 30 is optically detected by a change in the amount of reflected light. The other configurations are the same as those of the piezoelectric type, so the explanation will be omitted.

The rainfall sensor 20C using the magnetoelectric method has a coil C _L attached to the lower surface of the receiving plate 30, and this coil
A magnet is attached to the support member 29 at a position facing C _L.
Mg is fixed and the change in induced electromotive force generated in the coil C _L is detected. The other configurations are the same as those of the photoelectric system, so the explanation will be omitted.

On the other hand, vehicle body vibration detection sensors 22A, 22B, 2
As shown in FIGS. 7a, b, and c, 2C has the same configuration as each of the above-mentioned rainfall sensors 20A, 20B, and 20C, but the receiving plate 3
0 is covered with cover Ko to prevent raindrops from hitting it. Vehicle body vibration detection sensor 22A, 22B,
22C is attached at a position where a vibration component similar to the vibration component of the vehicle body 21 detected by the rainfall sensors 20A, 20B, and 20C can be obtained.

Next, a more detailed embodiment constructed based on the block diagram of FIG. 5 will be described with reference to FIG. 8. In the figure, the symbol Vcc is a terminal connected to a constant voltage power supply (not shown). Two strain gauges G in series that form the rainfall sensor 20 and two strain gauges G in series that form the vehicle body vibration detection sensor 22 are connected to this power supply terminal Vcc.
One end of the strain gauge G of each sensor 20, 22 is grounded. The connection point of each strain gauge G of the rainfall sensor 20 is connected to the non-inverting input terminal of the voltage comparator A 1 of the differential amplifier 23 via the resistor R ₁ , and the vehicle body vibration detection sensor 22 is connected to the inverting input terminal of the voltage comparator A ₁ of the differential amplifier 23 . The connection points of each strain gauge G are connected via a resistor _R2 . An external resistor R ₃ is connected between the inverting input terminal and the output terminal of the voltage comparator A ₁ ,
The output terminal of the voltage comparator A ₂ of the reference voltage generation circuit 31 is connected to the non-inverting input terminal via a resistor R ₄ . The inverting input terminal and output terminal of this voltage comparator A ₂ are short-circuited, and the non-inverting input terminal is connected to the voltage dividing resistor R ₅ ,
One end of the voltage dividing resistors _{R 5 and} R ₆ is connected to the power supply terminal Vcc, and the other end is grounded.

The output terminal of the voltage comparator A ₁ is connected to the non-inverting input terminal of the voltage comparator A ₃ in the AC amplifier 24.
Connected via _C1 . This non-inverting input terminal is connected via a resistor _R7 to the output terminal of the voltage comparator _A2 , and the inverting input terminal of the voltage comparator _A3 is connected to the output terminal via a resistor _R8 . A resistor _R9 is connected between the inverting input terminal and the output terminal of this voltage comparator _A3 .

The output terminal of the voltage comparator A ₃ is connected to the cathode of the diode D ₁ of the rectifier circuit 25, and its anode is connected to the inverting input terminal of the voltage comparator A ₄ via a resistor R ₁₀ . In addition, the anode of diode D ₂ is connected to the cathode of diode D ₁ , and its cathode is connected to the non-inverting input terminal of voltage comparator A ₄ together with one end of resistor R ₁₁ , and the other end of resistor R ₁₁ is connected to resistor R ₇ , connected to the connection point of _R8 . An external resistor _R12 is connected between the inverting input terminal and the output terminal of the voltage comparator _A4 .

The output terminal of voltage comparator A ₄ is the resistance of smoothing circuit 26
In addition to this resistor R ₁₃ , the smoothing circuit 26 is connected to one end of R ₁₃ , and includes resistors R ₁₄ , R ₁₅ , and a capacitor C ₂ ,
It is composed of C ₃ and C ₄ and is a so-called capacitor input type, with resistor R ₁₅ and capacitor C ₄
The connection point of is connected to the non-inverting input terminal of voltage comparator _A5 via resistor _R16 , and each connection point of capacitors _C2 , _C3 , and _C4 is connected to one end of resistor _R11 .
Further, the inverting input terminal and output terminal of voltage comparator _A5 are short-circuited.

The output terminal of voltage comparator A ₅ is connected to the non-inverting input terminal of voltage comparator A ₆ of comparator 27 via resistor R ₁₇ , and a resistor is connected between this non-inverting input terminal and the output terminal.
R ₁₈ is connected. A grounded capacitor _C5 is connected to the inverting input terminal of the voltage comparator _A6 , and a sliding terminal rd on the ground side of a variable resistor VR having two sliding terminals Ru and rd is connected.
One end of the variable resistor VR is connected to the power supply terminal Vcc,
The other end is grounded via resistor _R19 . The output of the voltage comparator A ₆ is connected to the transistor through the resistor R ₂₀
It is connected to the base of _T1 , its emitter is grounded, and its collector is connected to the power supply terminal Vcc via the excitation coil of the first relay _RY1 . The excitation coil of this first relay RY ₁ is connected in parallel with the excitation coil of the second relay RY ₂ , and the power terminal
Vcc is connected to the collector of the transistor T ₂ through the excitation coil of the third relay RY ₃ .
The emitter of this transistor T ₂ is grounded, its base is connected via a resistor R ₂₁ to the output of the voltage comparator A ₇ , and a resistor R ₂₂ is connected between this output and the non-inverting input. ing. In addition, the non-inverting input terminal of voltage comparator A ₇ is connected to resistor R ₁₇ via resistor R ₂₃ .
The inverting input terminal is connected to one end of the variable resistor.
Connected to the high voltage side sliding terminal ru of VR and the grounded capacitor C ₆ .

The symbol M is a wiper motor for driving the wiper,
The high voltage side terminal of this motor M is connected to power supply B,
The downstream low-speed mode terminal Lo is connected to one end of the normally open contact So ₂ of the second relay RY ₂ via the normally closed contact Sc ₃ of _the third relay RY 3 of the wiper drive mode selection circuit 28 . One end of this normally open contact So ₂ is connected to the intermittent amplifier 32 via the normally closed contact Sc ₁ of the first relay RY ₁ .
is connected to one input end of the Further, the other input terminal of the intermittent amplifier 32 is connected to the anode of a diode _D3 via a normally closed contact _{Sc2 of} a second relay RY2. Intermittent amplifier 32 is connected to power supply B, and its output end is connected to auto-stop switch As for intermittent mode. Furthermore, one end of the normally open contact So ₃ of the third relay RY ₃ is connected to the high speed mode terminal H _I on the other downstream side of the motor M, and the other end is connected to the normally closed contact Sc ₁ of the first relay RY ₁ . connected to one end. Also, the emitter of transistor _T3 is connected to power supply B, its collector is connected to power supply terminal Vcc, and its base is connected to resistor
Connected via R ₂₄ to the anode of diode D ₄ . The cathode of this diode _D4 is connected to the cathode of the diode _D3 and is also grounded via the wiper switch Ws.

Next, the action will be explained.

First, when it is necessary to wipe the wiper, close the wiper switch Ws.

As shown in FIG. 9a, the checkpoint A signal from the rainfall sensor 20 is a vibration component Po of the vehicle body 21 and an impact force signal component generated by the impact force of raindrops.
Pr is superimposed. Further, as shown in FIG. 9B, the check point signal from the vibration sensor 22 is only the vibration component Po of the vehicle body 21. In this way, when the output of each sensor 20, 22 is supplied to the dynamic amplifier 23, a signal corresponding only to the impact force signal component Pr due to the impact of raindrops (signal at check point C) is generated as shown in FIG. 9c. can get. The resistors R ₁ and R ₂ of the differential amplifier 23 are respectively r ₀ , and the resistors R ₃ and R ₄ are respectively
When r ₁ is assumed, the output of the differential intensifier 23 is r ₁ /r ₀ (e ₂ - e ₁ )+E. Here, e ₁ is the output voltage of the vehicle body vibration detection sensor 22, e ₂ is the output voltage of the rainfall sensor 20, and E is the reference voltage obtained from the reference power generation generation circuit 31.

In this way, the output of the differential amplifier 23 is amplified by the AC amplifier 24 and full-wave rectified by the rectifier circuit 25. This rectified signal becomes a DC level signal in the smoothing circuit 26, and the magnitude V of this level is proportional to the magnitude of the impact force signal component Pr corresponding to the impact force of raindrops.

When the output level V of the smoothing circuit 26 is small, that is, when the impact force of raindrops is small, the voltage comparator
Since the voltage at the non-inverting input terminals of A ₆ and A ₇ is small, each relay RY ₁ , of the wiper drive mode selection circuit 28
Both RY ₂ and RY ₃ do not operate. Therefore,
The intermittent amplifier 32 operates, and the wiper motor M rotates intermittently at a predetermined cycle by the action of the auto-stop switch As. That is, the wiper is driven in intermittent mode.

Next, due to an increase in rainfall, the smoothing circuit 26
When the output level V of the voltage comparator increases slightly, the voltage comparator
The potential at the non-inverting input terminal of _A6 rises, an output is obtained from its output terminal, and transistor _T1 is turned on.
Therefore the first relay RY ₁ and the second relay RY ₂
Each excitation coil is excited, the normally closed contacts Sc ₁ and Sc ₂ open, and the normally open contact So ₂ closes, so the intermittent amplifier 3
2 is stopped. i.e. normally closed contact Sc ₃
remains closed, the wiper motor M is connected to the low speed mode terminal _L0 , and the wiper is driven at low speed.

Then, the amount of rainfall increased further and the smoothing circuit 26
As the output level V of the voltage comparator increases further, the voltage comparator
Since the potential at the non-inverting input terminal of _A7 rises, an output is obtained from its output terminal and transistor _T2 turns on. Therefore, the excitation coil of the third relay RY ₃ is energized and the normally closed contact Sc ₃ is opened, and the normally open contact So ₃ is opened.
closes. That is, the wiper motor M is connected from the low speed mode terminal Lo to the high speed mode terminal H _I , and the wiper is driven at high speed.

As explained above, the present invention detects the impact force component generated by the impact force of raindrops together with the car body vibration component generated by car body vibration, and superimposes the impact force signal component on the car body vibration signal component. A rainfall sensor that outputs a detection output, a vehicle vibration detection sensor that outputs only a vehicle vibration signal component based on vehicle vibration, and a vehicle vibration signal component that is removed from the detection output in which an impact force signal component is superimposed on the vehicle vibration signal component. and a difference signal detector that extracts the impact force signal component based on the impact force of the raindrops, and subtracts the vehicle body vibration signal component from the detection output output from the rainfall sensor to calculate the impact force generated by the impact force of the raindrops. Since only the signal component is extracted, when extracting only the impact force signal component based on the impact force of raindrops from the rainfall sensor, a damper is installed between the vehicle body and the rainfall sensor to damp the vehicle body vibration component. We selected the damper material and matched the frequency characteristics of the damper and its bandpass filter in order to pass the vehicle body vibration signal component on which the impact force vibration component was superimposed through a bandpass filter and remove the vehicle body vibration signal component. In addition to being able to easily and reliably extract the impact force signal component based on the impact force without having to take such troublesome measures, this method also has the effect of preventing the damper-based rainfall sensor from deteriorating over time. play. As described above, since the impact force signal component based on the impact force of raindrops can be extracted, the wiper drive mode control device can be easily and reliably obtained.

[Brief explanation of the drawing]

Figures 1 to 4 are diagrams explaining conventional devices. Figure 1 is a block diagram of the wiper drive device, Figure 2 is a schematic configuration diagram of the sensor, and Figure 3 is the various vibrations obtained by the sensor. Frequency characteristic diagram of acceleration; Figures 4a, b, c, and d are waveform diagrams showing signal waveforms at check points w, x, y, and z in the block diagram of Figure 1; Figures 5 to 9 are 5 is a block diagram of a wiper drive mode control device, and FIG. 6 a, b, c is a diagram for explaining an embodiment of the present invention.
6A and 6B are schematic configuration diagrams showing each embodiment of the rainfall amount sensor, and FIG. 6A shows one using a piezoelectric method, FIG. 6B shows one using a photoelectric method, FIG. Figures a, b, and c are schematic configuration diagrams showing each embodiment of the vehicle body vibration detection sensor,
Fig. 7a shows a piezoelectric system, Fig. 7b shows a photoelectric system, and Fig. 7c shows a magnetoelectric system. A circuit diagram showing a detailed embodiment, FIGS. 9a, b, and c are check points A,
Figure 9a shows the output signal of the rainfall sensor, Figure 9b shows the output signal of the vehicle vibration detection sensor, and Figure 9c shows the output signal of the differential amplifier. It is. 20, 20A, 20B, 20C...Rainfall sensor, 21...Vehicle body, 22, 22A, 22B, 22
C... Vehicle body vibration detection sensor, 23... Differential amplifier (difference signal detector), 24... AC amplifier, 25...
Rectifier circuit, 26... Smoothing circuit, 27... Comparison circuit, 28... Wiper drive mode selection circuit.

Claims (1)

[Scope of Claims] 1. Provided at a portion of the vehicle body corresponding to the wiper wiper surface, it detects the impact force component generated by the impact force of raindrops together with the vehicle body vibration component generated by vehicle body vibration, and generates an impact force signal component. a rainfall sensor that outputs a detection output superimposed on a vehicle body vibration signal component, and a rainfall sensor that is installed at a vehicle body part that can detect a vehicle body vibration component equivalent to the vehicle body vibration component and outputs only a vehicle body vibration signal component based on the vehicle body vibration. a vehicle body vibration detection sensor; a difference signal detector that extracts an impact force signal component based on the impact force of the raindrops based on the difference between the outputs of the rainfall amount sensor and the vehicle body vibration detection sensor; A wiper drive mode control device comprising: a comparator for obtaining drive signals for various wiper drive modes. 2 The difference signal detector is a differential amplifier, the output of the differential amplifier is rectified by a rectifier circuit via an AC amplifier, and the output of the rectifier circuit is passed through a smoothing circuit to compare different levels and individually Claim 1 characterized in that the wiper drive mode selection circuit is supplied to each of a plurality of operating comparison circuits, and the output of each comparison circuit is supplied to operate the wiper drive mode selection circuit.
The wiper drive mode control device described in .