JPH03132449A - Vehicle speed sensitive variably pressing wiper device - Google Patents

Abstract

PURPOSE:To economize in power consumption by controlling an energizing force increasing/decreasing means formed of a motor for increasing/ decreasing energizing force for pressing a wiper blade to the glass surface according to vehicle speed and the like in such a way as to be placed in the non-operated state after the lapse of the specified time from the starting of its operation. CONSTITUTION:In a wiper arm 2 formed of an arm head 5 rigidly fixed at a wiper shaft and a wiper piece 7 pivotally fixed (6) at the arm head 5, one end of a coil spring 8 is connected in the vicinity of the play end part of the wiper arm 2, and the other end of the coil 8 is connected to a lever member 9 through a C-shape connecting member 11. In the arm head 5, there is provided with an energizing force increasing/decreasing means formed of a motor 14 and a slider 12 reciprocated being screwed with a male screw 15 fixed at the shaft of the motor 14, and the lever member 9 is oscillated by this operation through a hook member 13, thus increasing/decreasing energizing force. The motor 14 is controlled by a control circuit to increase/decrease energizing force according to the vehicle speed as well as to be stopped after the lapse of the specified time from the starting of its operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a vehicle speed-sensitive variable pressing force wiper device that can change the pressing force of a wiper blade against a glass surface of a vehicle depending on the vehicle speed.

<Prior Art> Generally, various vehicles are equipped with a wiper device to wipe away raindrops etc. adhering to the glass surface of the windshield. 1- It is known to be easier to understand. Various structures are known to prevent this lifting.
By using a lever that is reciprocated by a motor to expand and contract the spring that biases the wiper arm in a direction that increases the pressure force on the wiper blade against the glass surface, the tension of the spring is changed and the pressure force on the wiper blade is adjusted to the vehicle speed. A method is disclosed in which the information is automatically changed depending on the situation.

According to the above structure, the position of the wiper arm according to low and high vehicle speeds is detected by a switch circuit using contacts that slide on the conductive pattern, and the vehicle speed signal and position signal are compared and both signals are detected. The motors are driven in matching directions, and the motors are stopped when the contact reaches one of the two positions. However, if a foreign object gets caught in the mechanism that displaces the wiper arm, the wiper arm will not be displaced even if the motor is driven, and the position detection signal from the contact will not change, so there is a risk that the motor will continue to drive unnecessarily. was there.

<Problems to be Solved by the Invention> In view of the above-mentioned problems of the prior art, the main object of the present invention is to remove the wiper arm in an abnormal situation where the wiper arm is not displaced to a position where it generates a pressing force in accordance with the vehicle speed. It is an object of the present invention to provide a vehicle speed-sensitive variable pressure wiper device that can prevent unnecessary continuous driving for displacement.

[Structure of the Invention] Means for Solving the Problems According to the present invention, the present invention provides means for generating a force for urging a wiper arm in a direction to press a wiper blade against a glass surface, and = means for increasing or decreasing the 1 force, a biasing force detecting means for extracting a signal corresponding to the 1 force, and a force increasing/decreasing means for increasing or decreasing the bias force in accordance with the height of the vehicle speed. and a control circuit for setting the (=J force increasing/decreasing means into a non-operating state) when the signal of the biasing force detecting means reaches a value corresponding to the vehicle speed after the change. The device is characterized in that the control circuit includes first timer means for bringing the biasing force increasing/decreasing means into a non-operating state after a first predetermined time has elapsed from the start of operation of the force increasing/decreasing means. This is achieved by providing a vehicle speed-sensitive variable pressing force wiper device.Furthermore, the control circuit is configured to
If the signal of the biasing force detection means does not reach a value corresponding to the vehicle speed after the change after a predetermined period of time has elapsed, the biasing force increasing/decreasing stage is adjusted in the direction in which the (=J force increases) for a second predetermined period of time. It is preferable to include a second timer means for setting the device to a non-operating state after being activated.

<Operation> In this way, under normal conditions, the wiper arm is displaced to a position corresponding to the vehicle speed within a predetermined time determined by the timer means, but if the wiper arm does not complete its displacement within the predetermined time due to some abnormality, By setting the biasing force increasing/decreasing means in a non-operating state after a period of time has elapsed, it is possible to prevent the biasing force increasing/decreasing means from continuing to operate unnecessarily. Further, after the adjusting means is operated in a direction to increase the force on the wiper arm for a second predetermined time period by the second timer means, the adjusting means is brought into a non-operating state, whereby a high pressure state that can correspond to high-speed driving is achieved. be able to.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

FIG. 1 schematically shows a wiper device to which the present invention is applied, and as shown in the figure, a link mechanism (not shown) is attached to a wiper motor 1 installed inside the hood of an automobile. The proximal end portion of the wiper arm 2 is connected via the wiper arm 2. A wiper blade 3 is connected to the free end of the wiper arm 2, and the wiper blade 3 reciprocates in the direction of the arrow A in the figure to strike the glass surface 4 of the windshield at f=t.
It is designed to wipe away rainwater etc.

As shown in FIG. 2, the wiper arm 2 consists of an arm head 5 fixed to a wiper shaft (not shown) of the link mechanism described above, and a wiper piece 7 connected to the arm head 5 via a connecting pin 6. A wiper blade 3 is coupled to a free end (not shown) of the wiper piece 7 on the left side of the figure.

A tension coil spring 8 is located near the free end of the wiper piece 7.
One end is connected, and the other end of the coil spring 8 and a lever member 9 rotatably supported near the connecting pin 6 of the arm head 5 form a flat C-shaped connecting member 11. are connected to each other through. In this way, the wiper arm 2 is oriented so that the wiper blade 3 is pressed against the glass surface 4.
A means for generating a force that causes

A slider 12 is supported within the arm head 5 so as to be able to reciprocate in the direction of arrow B in FIG. 2, and a motor 14 is fixed to the rear of the slider 12 on the right side in the figure. A male thread 15 is coaxially fixed to the drive shaft of the motor 14, and a female thread 12a formed at the rear end of the slider 12 with an axis in the sliding direction is provided with a thread 1.
5 are screwed together. A hook member 13 is fixed to the tip of the slider 12, and a hook pin 13a fixed to the tip of the hook hole 13 engages with a slot 9a formed in the free end of the lever part 9. There is.

Therefore, by rotating the motor 14 as a biasing force increasing/decreasing means in the forward and reverse directions by a control device to be described later, the slider 12 reciprocates in the direction of arrow B in the figure, the slot 9a is guided by the hook pin 13a, and the lever shaft 9 Arrow C in the diagram
It will be moved back and forth in the direction of. Then, the connection part month 1
Since the coil spring 8 is expanded and contracted via the coil spring 1, the urging force of the wiper arm 2 can be adjusted, and the pressing force of the wiper blade 3 against the glass surface 4 can be adjusted. Further, a contact 16 is fixed to the slider 12, and
A wiring board 17 is fixed to the arm head 5, and when the contacts 16 come into sliding contact with the wiring board 17I, a position signal corresponding to the tension of the coil spring 8 is transmitted to the contact 1.
6 to a control circuit to be described later. In this way, by detecting the position of the wiper arm 2 corresponding to the pressing force of the wiper blade 3, the pressing position sensor 18 is configured as a biasing force detecting means.

This control circuit includes an ICI for comparing the vehicle speed and the position signal of the wiper arm 2 and generating a control signal for rotating the motor 14 in the forward and reverse directions. A vehicle speed pulse from a vehicle speed center (not shown) is transmitted via a vehicle speed signal generation circuit 22 to
The vehicle speed signal is divided into three vehicle speed signals: a high speed signal, a medium speed signal, and a low speed signal, and is input to input terminals 11 to I3 of the IC1. Further, a position signal corresponding to the position of the contact 16 of the above-mentioned wiring board 17 is manually input to the input terminals 14 to I6 of the IcI as a 3-bit digital signal.

As shown in FIG. 4, three conductive patterns 23a to 23c are formed on the wiring board 17 in parallel with each other.

The contact 16 is formed in the shape of a comb tooth divided into three parts, and each contact portion of each free end portion moves the corresponding conductive patterns 23a to 23C in the direction of the arrow in the figure as the slider 12 is displaced. It is designed to reciprocate in the direction shown in and make sliding contact. Note that the contact 16 is grounded, and the conductive pattern 23a in contact with the contact 16
~23c becomes grounded.

As shown in FIG. 3, each conductive pattern 23a to 23
c is connected to the power supply terminal VC via the respective corresponding resistors R1 to R3 and a common diode D1 in series, and is applied with a predetermined voltage, and each corresponding pair of resistors R4 and R5, It is connected to each input terminal 14 to I6 of the ICI via R6 and R7, and R8 and R9 in series. In addition, each pair of resistors mentioned above is grounded via each capacitor 01 to C3, and each input terminal is connected to
I6 is grounded via each Zener diode ZD1 to ZD3.

The position signal corresponding to the biasing force of the wiper arm 2 is determined by the contact state between the contact 16 and the conductive patterns 23a to 23c in each section a to h shown in FIG. 4, as shown in the table below. It becomes a bit digital signal and is input to each input terminal rI4 to I6. In the table, the state in which the contacts 16 are not in contact with the conductive patterns 23a to 23c is represented by 1, and the state in which the contacts 16 are in contact is represented by 0.

(Left below) 0 Also, section aSC% eSg is the stop position, and section a
The side is the lowest pressure side, and the section side is the highest pressure side. According to this embodiment, the conductive pattern 2 is placed on the side with a lower pressing force.
3a to 23c and the contacts 16 are in a non-contact state (1), so that the contacts 16 and the conductive patterns 23a to 23c are in a non-contact state (1).
In the case of an open failure in which there is no contact, such as when a foreign object is caught between the 23c and the 23c, the judgment is made in the direction of increasing the pressing force. can be suitably prevented from decreasing.

The ICI is equipped with output terminals 01 and 02 for comparing a vehicle speed signal and a position signal of the wiper arm 2 and outputting a forward/reverse drive signal to the motor 14.
is connected to a pressure side drive circuit that increases the pressing force of the wiper blade 3, and the output terminal 02 is connected to a pressure reduction side drive circuit that reduces the pressing force. That is, the output terminal 01 is connected to the base of the transistor Trl whose emitter is grounded and which constitutes the pressure side drive circuit, and the base of the transistor Tri is connected to the power supply terminal Vc via the resistor RIO. The base and emitter are connected via a capacitor C4. A coil of a relay Ryl and a diode for protecting the transistor are connected between the collector of the transistor Tri and the power supply terminal Vc. A common terminal r of the contact of the relay Ryl is connected to one terminal of the motor 14, and when the relay Ryl is off, the contact is grounded, and when the relay Ryl is on, it is connected to the power supply terminal Vc.

Similarly, the output terminal 02 is connected to the base of the transistor Tr2 which is connected to the emitter and the vine that constitutes the pressure reduction side drive circuit, and the resistor R11, capacitor C5, and relay Ry2 are configured in the same way as the pressure side drive circuit. The common terminal of the contact of relay Ry2 is connected to the other end of motor 14.

For example, when the vehicle speed reaches a speed corresponding to a low speed state and a low speed signal is input from the vehicle speed signal generating circuit 22 to the input terminal 11 of the IcI,: 1 TANK!・The motor 14 is driven until the motor 16 reaches the section C, and similarly, when the medium speed signal is input to the input terminal ■2, the motor 14 is contacted.
When the high-speed signal is input to the input terminal 13, a pressure-side drive signal is output from the output terminal 01 of the ICI to drive the motor 14 until the contact 16 reaches the interval g. When the vehicle speed decreases, a pressure reduction side drive signal is output from the output terminal 02 of the ICI in accordance with each vehicle speed.

The output terminal 03 of the ICI is connected to the input terminal 1 of the first timer 24a of the IC2 via the resistor R12,
The resistor R12 and the input terminal ICL are grounded via a capacitor C6. The IC2 includes the first timer section 24a and the second timer section 24b described above, and the output terminal J'-04 of the ICI is connected to the resistor R1.
3 at the input terminal 2 of the second timer section 24b, and the connection between the resistor R1B and the input terminal 2CL is grounded via the capacitor C7.

The input terminal IA of the first timer section 24a is grounded,
The output terminal IQ is connected to the input terminal I7 of the ICI, and one output terminal is connected to the input terminal 11 of the IC3 as a flip-flop circuit. The output terminal 03 of the ICI is connected to the other input terminal I2 of the IC3. Also, the output terminal 01 of IC3 is connected to the second
It is connected to the input terminal 2W of the timer section 24b, and the resistor R14 and the input terminal 2X are grounded via a capacitor C8.

-I- The output terminal 2Q of the second timer section 24b is I
It is connected to the input terminal I8 of C1, and the resistor R1
It is also connected to the input terminal J'-14 of IC3 via 5. Note that the resistor R15 and the input terminal (4) are grounded via a capacitor C9.

Further, two output terminals of the second timer section 24b are connected to an input terminal I3 of Ic3, and both input terminals I3,
Depending on the input conditions to I4, IC3 acts as a flip-flop circuit, and the output terminal 02 of IC3 is connected to the input terminal I9 of ICI.

Next, the operating procedure of this embodiment will be described as time chart 1 in FIG.
is shown below with reference to. The left half of Fig. 5 shows time chart 1 during normal operation, when the wiper device is used and the contact 16 is located in section C in response to the vehicle speed signal during low-speed driving, when the vehicle speed is -1- When a medium-speed vehicle speed signal is manually input to the input terminal I2 of the ICI by increasing the speed, the pressurizing side is driven from the output terminal 01 of the ICI in order to drive the motor 14 in the direction of increasing the pressing force of the wiper blade. A signal is output. During normal operation, the contact 16 moves to the section d as the slider 12 is moved by the motor 14. At the same time, a high level (hereinafter referred to as H level) signal is output from the output terminal 03 of the ICI, and the first
Since the input terminal 1°CU of the timer section 24a becomes H level, an H level signal is output from the output terminal IQ, and a low level (hereinafter referred to as L level) signal is output from the output terminals 1 to 1.
is output. Note that the input terminal r2 of the second timer section 24b
Since CL is at H level and input terminal 2W is at H level, an L level signal is output from output terminal 2Q, and an H level signal is output from output terminal 2u.

As described in , the contact 1 is driven by the motor 14.
6 reaches the interval e corresponding to the medium speed state from the interval d,
Due to the position signal, the motor drive signal from output terminal 01 of the ICI is stopped, and the motor drive signal from output terminal 01 of the ICI is stopped.
The output signal of No. 3 also returns from the H level to the L level, and the input terminal ICL of the first timer section 24a also becomes the L level. At this time, the states of both output terminals IQ and IQ of the first timer section 24a return to their original states because the input terminal ICL becomes L level within a predetermined sub-time t1 shown by the imaginary line. return. Then, one output terminal 2Q of the second timer section 24b, which serves as an input signal to the input terminal I4 of the IC3, remains at the L level, and the other output terminal 2 is at the H level.
Since it remains at the H level, the output terminal 02 as a flip-flop of IC3 remains at the H level. Also, I
The input terminal ■1° of c3 receives an H level signal from the output terminal 1 of the first timer section 24a, and the input terminal 12 of IC3 receives an L level signal from the output terminal 03 of ICI. Then, the output terminal 01 of the IC3 is set to the H level, and the second timer section 24b does not enter the timing start state.

The right half of Figure 5 shows the abnormal state, 1-
Similarly to the above, when the state changes from a low-speed running state to a middle-speed running state, even if a drive signal is output from the output terminal 01 of the ICI to the motor 14 due to the manual input of the medium-speed signal, a foreign object may become caught in the link mechanism of the wiper arm 2, etc. In the event of an abnormality in which the wiper arm 2 cannot be displaced, the contact 16 also does not move, and the position signal in the state of section C continues to be manually input to the ICI. Therefore, in order to displace the wiper arm 2 in a direction that moves the contacts 6 1 and 16 to the section e, the motor 14 is connected to the output terminal 01 of the ICI.
Since the drive signal continues to be output to the output terminal 0 of IC1,
3 remains at H level, the first timer section 24
The input terminal rlcL of a remains at H level.

When the time-up occurs due to the elapse of the secondary time t1, the output terminal IQ of the first timer section 24a goes to the L level, and the L level
The level signal is manually input to the ICI input terminal ■7, but the IC
The H level signal from the output terminal 03 of IC3 is inputted to the input terminal I2 of IC3, and the signal (which has reached the H level of the output terminal once) is inputted to the input terminal 11 of IC3. The output terminal 01 is set to the L level, and the second timer section 24b starts timing.At this time, the output terminal 2Q of the second timer section 24b becomes the H level, and the input terminal 8 of the IC1 becomes the H level. level, the output terminal 01 of the ICI is set to H level, a drive signal is output, and the motor 14 is driven in a direction in which the pressing force of the wiper blade 3 increases for a predetermined sub-time t2.

Then, the second timer section 24b measures a predetermined time t2.
When the time-up occurs due to the passage of time, the output terminal 0 of IC3
2 outputs an L level signal, and the input terminal I9 of IC1 becomes L level, so that the output terminals 01 and 02 of IC1
is set to L level, the drive signal is stopped, and motor 1 is turned on.
4 stops.

In this way, during normal operation, the time tl of the first timer section 24a
However, in an abnormal situation where the wiper arm 2 cannot be displaced, the position signal from the pressure sensor 17 does not change even after time t1 has elapsed, so the motor 14 stops moving until the vehicle speed signal and the position signal match. However, following the time-up of the first timer section 24a, the second timer section 24b starts at 4 o'clock, and the motor 14 increases the pressing force of the wiper blade 3 only during the measured time t2. The motor 14 continues to be outputted with a drive signal, and the drive of the motor 14 is stopped after the measured time t2 has elapsed. Therefore, in the event of a failure in which the wiper arm 2 cannot be displaced and a drive signal continues to be output to the motor 14, current will not continue to flow unnecessarily to the motor 14, and the pressing force of the wiper blade 3 during running will be maintained at a high level. By doing so, it is possible to secure a 1° wiping ability that is compatible with high-speed driving. In addition, when the above processing is performed in the event of an abnormality, the control circuit is placed in a hold state so that the control circuit is not reset until, for example, the ignition switch is turned off, thereby preventing malfunctions after an abnormal condition occurs. are doing.

Next, a second embodiment will be described below with reference to FIG.

In this second embodiment, the input terminal 11 and I
2, a 2-bit vehicle speed signal from a vehicle speed signal generation circuit 25 is manually generated. Furthermore, position signals from the pressed position sensor 18 and contacts 16, which are the same as those in the embodiment described above, are converted into 3-bit signals from the conductive patterns 23a to 23C, as in the embodiment described above. The conductive pattern 23a is
It is connected to one of the pair of input terminals of the exclusive OR circuit EXI via the resistors R4, R5 and the NOT circuit NT1 in this order. In addition, the conductive pattern 23b
However, the conductive pattern 23C connects the pair of inputs to the exclusive OR circuit EX2 through the resistors R6, R7 and the NOT circuit NT2 in the same manner as described in Section 2. The terminals r- are connected to each other.

The output terminal of the exclusive OR circuit EX2 is connected to the other input terminal of the exclusive OR circuit EXI described below. The output terminal of the exclusive OR circuit EXI is connected to I3 of ■3 to I5 as position signal input terminals of IC4, and the exclusive OR circuit EXI
The output terminal of is connected to the input terminal I4, and the not circuit NT
The output terminal 3 is connected to the input terminal I5, and a 3-bit position signal is input to the IC4 as in the previous embodiment.

The three output terminals 01--03 of the IC4 are configured to output H-level signals according to the comparison result between the vehicle speed signal and the position signal. That is, when the position signal is on the low voltage side with respect to the city speed signal 0, the output terminal 01 goes to the H level, and when the vehicle speed signal and the position signal match, the output terminal 02 goes to the H level, and the vehicle speed When the position signal is on the high voltage side with respect to the signal, the output terminal 03 becomes H level.

The output terminal 01 is connected to one of the three input terminals of the AND circuit ADI, the output terminal of the AND circuit AD1 is connected to one of the pair of input terminals of the OR circuit ORI, and the output terminal of the OR circuit ORI is , is connected via a resistor R21 to the base of a transistor Trl whose emitter is grounded, which constitutes a pressure-side drive circuit that drives the motor 14 in a direction to increase the pressing force of the wiper blade 3. The base and emitter of the transistor Tri are connected through a resistor R22, and a relay R5/1 is connected to the collector of the transistor Tri in the same configuration as in the previous embodiment.

The output terminal 03 is connected to one of the three input terminals of the AND circuit AD2, and the output terminal of the AND circuit AD2 is connected to one of the pair of input terminals of the NAND circuit NDI.
The output terminal of the NAND circuit NDI is emitter grounded and constitutes a pressure reduction side drive circuit that drives the motor 14 in a direction that reduces the pressing force of the wiper blade 3 via the knot circuit NT5 and the resistor R23 in this order. Tr2
connected to the base of. '' 1, the base and emitter of the transistor Tr2 are connected through the resistor R24, and the relay Ry2 is connected to the collector of the transistor Tr2 in the same configuration as the previous embodiment, and both relays Ryl , the motor 14 between the common terminals of Ry2.
is connected.

The output terminal 02 is connected via a circuit NT4 to an input terminal ICL of a first timer 26 which operates in the same manner as the first timer section 24a of the embodiment described above, and is connected to a pair of OR circuits OR2. is connected to one of the input terminals. The output terminal of this OR circuit OR2 is connected via a resistor R25 to two input terminals of a second timer 27 which performs the same function as the second timer section 24b of the embodiment described above. Note that the resistor R25 and the two input terminals are grounded via a capacitor C9. Input terminal IA of first timer 26
is grounded, its output terminal IQ is connected to one of the input terminals r of the AND circuit AD2, and the output terminals are connected to the OR circuit OR through the NOT circuit NT6.
is connected to the other input terminal f of 2.

By the way, the output terminal of the exclusive OR circuit EX1 is connected to the output terminal of the AND circuit AT3 via the NO) circuit NT7.
The output terminal r of the exclusive OR circuit EX2 is connected to one of the input terminals of the AND circuit AD.
NT3 is connected to the other one of the input terminals r of NT3.
The output terminal r- of is the remaining one of the input terminals of the AND circuit AD3.
connected to. The output terminal r. of this AND AD3 is connected to the input terminal 2U of the second timer 27 via a NOT circuit NT8.

The output terminal 2Q of the second timer 27 is connected to the other input terminal of the OR circuit OR1, and the output terminals 2 are connected to the other input terminal of the NAND circuit NDI. Further, the output terminal 2Q is connected to one of a pair of input terminals of the flip-flop circuit 28 via a resistor 3R26, and the output terminals 2 are connected to the other input terminal of the flip-flop circuit 28. still,
The resistor R26 and one terminal of the flip-flop circuit 28 are grounded via a capacitor C10.

The flip-flop circuit 28 is constructed by combining three Nant gates as shown in the figure. The output terminal of the flip-flop circuit 28 is a double AND circuit ADI.
, AD2 are connected to the remaining input terminals of AD2.

Next, the operation procedure of the second embodiment described above will be described below with reference to the time chart of FIG. In FIG. 7, as in FIG. 5, the left half shows a time chart 1 in a normal state, and the right half shows a time chart in an abnormal state.

Furthermore, detailed explanations of the same parts as in the above embodiments will be omitted.

In normal operation, as in the embodiment described above, the output terminals 01.02 of the IC4 return to their original states by the time the first timer 26 times out due to the passage of elapsed time t1, so that when the output terminal 01 becomes L level, Since the output of the AND circuit ADI becomes L level, the OR circuit OR
The output of I also becomes L level, and the drive of the motor 14 is stopped. Therefore, as shown by the imaginary line in the figure, ICL becomes L level before the time-up of the first timer 26, and its output terminals become H level, causing the NOT circuit NT6.
The L level signal from L is input to the OR circuit OR2, but
Since the output terminal 02 of c4 is at H level, the second
An H level signal is input to the input terminal 2W of the timer 27, and the second timer 27 never starts timing.

In the event of an abnormality, the press position sensor 18 is activated as in the above embodiment.
Since the position signal of IC4 is not switched and the output signal of output terminal 02 of IC4 remains at L level, the first timer 26
The second timer 27 starts at 31:00 because the output signal of the output terminal becomes H level when the time-up occurs. In response to the 1 o'clock start of the second timer 27, the output terminal J'2Q becomes the 1■ level, so that the pressure side drive circuit Ryl is turned on, and the wiper blade 2 is activated as in the previous embodiment. The motor 14 continues to be driven to the side that increases the pressing force. When the second timer 27 times up, the output of the flip-flop circuit 28 becomes L level, so the outputs of both AND circuits AD1 and AC3 become L level, and the relays Ryl and Ry2 of both drive circuits are turned off. The drive of the motor 14 is stopped.

This second embodiment also provides the same effects as the previous embodiment. That is, if the position adjustment of the wiper arm 2 is not completed by the time the first timer 26 times up, the second timer 27 starts counting, and within the time t2, the motor 14 is activated in a direction to increase the pressing force of the wiper blade 3. After driving to maintain the pressing force of the wiper blade 3 at a high pressure state, the driving of the motor 14 is stopped when the second timer 27 times up. Further, as in the embodiment described above, it is possible to set the ignition switch to the 1st state under conditions such as turning off the ignition switch.

In this second embodiment, at high speed, the position signal of the maximum pressing position becomes an L level signal via the knot circuit NT8, and is inputted to the input terminal 2CL of the second timer 27. That is, at high speed, since the wiper blade 3 is in the maximum pressing state, there is no need to displace the wiper arm 2 in the direction of increasing the pressing force within time t2 at 31 o'clock.
The timer 27 does not measure time.

Further, in each of the above embodiments, the circuit is constructed by combining various ICs, but it may be controlled using a microcomputer.

[Effects of the Invention] As described above, according to the present invention, the means for increasing and decreasing the force (=j) of the wiper arm can be activated within a predetermined time by the timer means under normal conditions, but due to some abnormality, the j If the signal of the force detecting means does not have a value corresponding to the vehicle speed, the urging force increasing/decreasing means is made inactive after a predetermined period of time to prevent the urging force increasing/decreasing Er stage from continuing to operate unnecessarily. It is possible to prevent current from continuing to flow unnecessarily, for example when a motor is used as the force increase/decrease means.Furthermore, it is possible to prevent the current from continuing to flow unnecessarily.
By activating the force increasing/decreasing means to increase the biasing force of the wiper arm for a predetermined period of time, and then deactivating the force increasing/decreasing means, the pressing force of the wiper blade is kept high to ensure sufficient wiping ability for high-speed driving. The effects are extremely personal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing a vehicle speed sensitive variable pressure wiper device to which the present invention is applied. FIG. 2 is a longitudinal sectional view showing the main parts of the wiper device. FIG. 3 is a circuit diagram showing a first embodiment of the control circuit of this device. FIG. 4 is an explanatory diagram showing a press position sensor of the present device. FIG. 5 is a time chart showing the operation procedure of the first embodiment. FIG. 6 is a diagram showing a control circuit of the second embodiment. FIG. 7 is a tie 8 whipyard showing the operation procedure of the second embodiment. 1... Wiper motor 2... Wiper arm 3...
・Wiper blade 4...Glass surface 5...Arm head 6...Connecting pin 7...Arm piece 8
...Coil spring 9...Lever shrine 9a...
Slot 11...Connecting part 12...Slider 12a...Female thread part 13...Hook part 13a
...Hook pin 14...Motor 15...Male thread 16...Contact 17...Wiring board
18... Press position sensor 22... Vehicle speed signal generation circuit 23a-23c... Conductive pattern 24... Timer circuit 24a... First timer section 2
4b...Second timer section 25...Vehicle speed signal generation circuit 2
6...First timer section 27...Second timer 28...
・Flip-flop circuit

Claims (2)

[Claims] (1) Means for generating a force that urges the wiper arm in a direction that presses the wiper blade against the glass surface, means for increasing or decreasing the urging force, and urging force detection for extracting a signal corresponding to the urging force. and the urging force increasing/decreasing means is operated to increase or decrease the urging force according to the height of the vehicle speed, and when the signal of the urging force detecting means reaches a value corresponding to the changed vehicle speed, the urging force is increased or decreased. A vehicle speed sensitive variable pressure wiper device comprising: a control circuit for putting the increasing/decreasing means into a non-operating state; A vehicle speed sensitive variable pressure wiper device comprising a first timer means for putting the means into a non-operating state. (2) The control circuit causes the biasing force increase/decrease unit to increase the biasing force when the signal of the biasing force detection unit does not have a value corresponding to the vehicle speed after the change after the first predetermined time has elapsed. 2. The vehicle speed-sensitive variable pressure wiper device according to claim 1, further comprising a second timer means for operating the wiper device in the direction of the wiper for a second predetermined period of time and then setting the wiper device to a non-operating state.