JP2562058B2 - Speed sensitive pressure variable wiper device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Use] The present invention relates to a vehicle speed sensitive variable pressure wiper device capable of changing the pressing force of a wiper blade against a glass surface of a vehicle according to the vehicle speed.

<Prior Art> Generally, various vehicles are provided with a wiper device for wiping off raindrops and the like adhering to the glass surface of the windshield, but the wiper blade is easily lifted by running wind at high speed running. Is known to be.
Various structures are known to prevent this floating, and for example, in Japanese Patent Laid-Open No. 187636/1987, a spring for urging the wiper arm in the direction of increasing the pressing force of the wiper blade against the glass surface is used as a motor. It is disclosed that the tension of the spring is changed and the pressing force of the wiper blade is automatically changed according to the vehicle speed by expanding and contracting using a lever that reciprocates.

According to the above structure, the position of the wiper arm corresponding to the low vehicle speed and the high vehicle speed is detected by the switch circuit using the contact sliding on the conductive pattern, and the vehicle speed signal and the position signal are compared, and both signals are detected. The motor is driven in the same direction, and the drive of the motor is stopped when the contact reaches one of the two positions. However, when foreign matter is caught in the mechanism for displacing the wiper arm, the wiper arm does not move even when the motor is driven, and the position detection signal by the contact does not change, so that the current may continue to flow unnecessarily in the motor. There was In such a case, it is good to provide a means for prohibiting the electric current from flowing unnecessarily to the motor, but it is possible that an abnormality occurs during running in the low press state and the driving of the motor is stopped in the low press state. When high speed running is performed in such a state, there arises an inconvenience that a sufficient wiping ability cannot be secured.

<Problems to be Solved by the Invention> In view of the problems of the conventional technology as described above, a main object of the present invention is to provide a wiper arm in an abnormal state such that the wiper arm is not displaced to a position where a pressing force corresponding to a vehicle speed is generated. It is an object of the present invention to provide a vehicle speed sensitive pressing variable wiper device which can prevent unnecessary continuous driving and can also support high speed traveling.

[Constitution of the Invention] <Means for Solving the Problems> According to the present invention, a means for generating a force for urging the wiper arm in a direction of pressing the wiper blade against the glass surface, Means for increasing / decreasing the force, urging force detecting means for extracting a signal corresponding to the urging force, and activating the urging force increasing / decreasing means so as to increase / decrease the urging force according to the level of the vehicle speed, A vehicle speed sensitive pressing variable wiper device having a control circuit for deactivating the urging force increasing / decreasing means when the signal from the urging force detecting means reaches a value corresponding to the changed vehicle speed. A circuit includes first timer means for enabling the urging force increasing / decreasing means to be operable within a first predetermined time from the start of operation of the urging force increasing / decreasing means, and a second timer after the first predetermined time has elapsed. Within the specified time Second timer means for making the increasing / decreasing means operable, and when the signal of the urging force detecting means has not reached a value corresponding to the changed vehicle speed by the lapse of the first predetermined time. After that, the urging force increasing / decreasing means is actuated in the direction in which the urging force increases for the second predetermined time, and then is held in the non-operating state.

<Operation> In this way, in a normal state, the wiper arm is displaced to a position corresponding to the vehicle speed within a predetermined time by the timer means, but if the wiper arm is not completely displaced within the predetermined time due to some abnormality, After the elapse of the predetermined time of 1, the adjusting means is actuated in such a direction as to increase the biasing force of the wiper arm by the second timer means for the second predetermined time, and then the adjusting means is made inoperative, so that a high pressing force corresponding to high-speed traveling can be obtained. Can be in a state.

<Embodiment> Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an outline of a wiper device to which the present invention is applied. As shown in the figure, a wiper motor 1 mounted in a hood of an automobile has a wiper arm 2 through a link mechanism (not shown). The ends are connected. A wiper blade 3 is connected to the free end of the wiper arm 2 so that the wiper blade 3 reciprocates in the direction of arrow A in the figure to wipe off rainwater and the like adhering to the glass surface 4 of the windshield. ing.

As shown in FIG. 2, the wiper arm 2 includes an arm head 5 fixed to a wiper shaft (not shown) of the link mechanism described above, and a wiper piece 7 pivotally connected to the arm head 5 via a connecting pin 6. The wiper blade 3 is connected to a free end (not shown) of the wiper piece 7 on the left side in the drawing. One end of a tension coil spring 8 is coupled near the free end of the wiper piece 7, 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. Are connected to each other via a flat C-shaped connecting member 11. In this way, the means for generating the force for urging the wiper arm 2 in the direction in which the wiper blade 3 is pressed against the glass surface 4 is configured.

A slider 12 is reciprocally supported in the arm head 5 in the direction of arrow B in FIG.
A motor 14 is fixedly installed on the rear side which is the right side of the figure.
A male screw 15 is coaxially fixed to the drive shaft of the motor 14, and the screw 15 is screwed to the screw portion 12a because the male screw 15 is formed at the rear end of the slider 12 so as to have an axis in the sliding direction. . 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 member 13 is provided.
Engages with the slot 9a formed at the free end of the lever member 9.

Therefore, the slider 12 reciprocates in the direction of arrow B in the drawing by the motor 14 as a biasing force increasing / decreasing means being rotated forward and backward by the control device to be described later, and the slot 9a is guided by the hook pin 13a so that the lever member 9 is moved. It will be reciprocated in the direction of arrow C in the figure. Then, since the coil spring 8 is expanded and contracted via the connecting member 11, 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 fixedly mounted on the slider 12, and a wiring board 17 is fixed to the arm head 5. The contact 16 slides on the wiring board 17 to cope with the tension of the coil spring 8. The position signal to be transmitted is sent to the control circuit described later via the contact 16. Thus, by detecting the position of the wiper arm 2 corresponding to the pressing force of the wiper blade 3, the pressing position sensor 18 as the urging force detecting means is configured.

The control circuit includes an IC 1 for comparing the vehicle speed signal with the position signal of the wiper arm 2 to generate a control signal for rotating the motor 14 in the forward and reverse directions. A vehicle speed pulse from a vehicle speed sensor (not shown) is divided into three vehicle speed signals of a high speed signal, a medium speed signal and a low speed signal via a vehicle speed signal generation circuit 22 and input to input terminals I1 to I3 of IC1. . Also, I
A position signal corresponding to the position of the contact 16 on the wiring board 17 is input to the input terminals I4 to I6 of C1 as a 3-bit digital signal.

On the wiring board 17, as shown in FIG. 4, three conductive patterns 23a to 23c are formed in parallel with each other. The contact 16 is formed in the shape of a comb tooth that is divided into three parts, and each contact portion by each free end portion corresponds to each conductive pattern 23a.
23c, the slider 12 is reciprocated in the direction shown by an arrow D in FIG.
The contact 16 is grounded, and the conductive patterns 23a-23c in contact with the contact 16 are grounded.

As shown in FIG. 3, each conductive pattern 23a-23c
Is connected to the power supply terminal Vc through the corresponding resistors R1 to R3 and the common diode D1 in series, and a predetermined voltage is applied to the resistors R4 to R5 and R6. And R7, R8 and R9 in series
1 is connected to each input terminal I4 to I6. The pair of resistors are grounded via the capacitors C1 to C3, and the input terminals I4 to I6 are grounded via the Zener diodes ZD1 to ZD3.

The position signal corresponding to the urging force of the wiper arm 2 is the fourth signal.
Depending on the contact state between the contact 16 and the conductive patterns 23a to 23c in each of the sections a to h shown in the drawing, a 3-bit digital signal as shown in the table below is obtained, and the input terminals I4 to I6 are shown. To enter. In the table, the conductive pattern 23
The state in which the contact 16 is not in contact with a to 23c is represented by 1, and the state in which the contact 16 is in contact is represented by 0.

Sections a, c, e, and g are stop positions, and section a
The side is the lowest pressing side, and the section h side is the highest pressing side. According to the present embodiment, the side with the lower pressing force is the conductive pattern.
Since the non-contact state (1) between the contacts 23a to 23c and the contact 16 is set, the pressing force is applied to the open failure in which the contact 16 and the conductive patterns 23a to 23c are in the non-contact state in which foreign matters are caught. It will be decided to raise,
It is possible to suitably prevent the pressing force from being reduced during traveling due to the above-mentioned failure and the wiping ability from being reduced.

The IC1 is provided with output terminals O1 and O2 for comparing the vehicle speed signal and the position signal of the wiper arm 2 and outputting a forward / reverse drive signal to the motor 14, and the output terminal O1 is provided for the wiper blade 3. The output signal O2 is connected to a pressure side drive circuit that increases the pressing force, and the output signal O2 is connected to a pressure reduction side drive circuit that decreases the pressing force. That is, the output terminal O1 is connected to the base of the transistor Tr1 whose emitter is grounded, which constitutes the pressurizing side drive circuit, and the base of the transistor Tr1 is connected to the power supply terminal Vc via the resistor R10.
A capacitor C4 is placed between the base and emitter of the transistor Tr1.
Connected through. The coil of the relay Ry1 and the diode for transistor protection are connected between the collector of the transistor Tr1 and the power supply terminal Vc. Relay ry
The common terminal of the contact 1 is connected to one terminal of the motor 14, and the contact is grounded when the relay Ry1 is off and connected to the electronic terminal Vc when it is on.

At the same time, the output terminal O2 is connected to the base of the transistor Tr2 whose emitter is grounded, which constitutes the pressure reducing side drive circuit, and the resistor R11, the capacitor C5, and the relay Ry2 are configured in the same manner as the pressure side drive circuit. The common terminal of the contact of is connected to the other end of the motor 14.

For example, when the vehicle speed increases and reaches the vehicle speed corresponding to the low speed state and the low speed signal is input from the vehicle speed signal generation circuit 22 to the input terminal I1 of IC1, the motor 14 is driven until the contact 16 reaches the section c. Similarly, when a medium speed signal is input to the input terminal I2, the contact 16 reaches the section e, and when a high speed signal is input to the input terminal I3, the contact 16 reaches the section g. IC1 to drive
The pressurizing side drive signal is output from the output terminal O1 of. If the vehicle speed decreases, the output terminal O2 of IC1
A pressure reduction side drive signal is output from.

The output terminal O3 of the IC1 is connected via the resistor R12 to the input terminal 1 of the first timer 24a as the first timer means of the IC2.
And the resistor R12 and the input terminal 1 () are grounded via the capacitor C6. The IC2 includes the above-mentioned first timer section 24a and the second timer section 24b as the second timer means, and the output terminal O4 of the IC1 is connected to the input terminal 2 of the second timer section 24b via the resistor R13. It is connected to ▲ ▼, and the resistor R13 and the input terminal 2 ▲ ▼ are grounded via a capacitor C7.

The input terminal 1 of the first timer unit 24a is grounded,
Output terminal 1Q is connected to input terminal I7 of IC1 and output terminal 1
Is connected to an input terminal I1 of an IC3 formed of a flip-flop circuit as an operation prohibiting means. The output terminal O3 of IC1 is connected to the other input terminal I2 of IC3. Further, the output terminal O1 of the IC3 is connected to the second timer unit via the resistor R14.
It is connected to the input terminal 2 of 24b, and the resistor R14 and the input terminal 2 are grounded via the capacitor C8.

The output terminal 2Q of the second timer unit 24b described above is connected to the input terminal I8 of the IC1 and also to the input terminal I4 of the IC3 via the resistor R15. The resistor R15 and the input terminal I4 are grounded via the capacitor C9. The output terminal 2 of the second timer section 24b is the input terminal I3 of the IC3.
IC3 acts as a flip-flop circuit depending on the input conditions to these input terminals I3 and I4.
Output terminal O2 of is connected to input terminal I9 of IC1.

Next, the operating procedure of this embodiment will be described below with reference to the time chart of FIG. In the left half of FIG. 5, a time chart for normal operation is shown, and when the wiper device is used and the contact 16 is located in the section c in response to the vehicle speed signal at low speed traveling, the vehicle speed increases. Input terminal I2 of IC1
When a vehicle speed signal in the medium speed state is input to, in order to drive the motor 14 in the direction of increasing the pressing force of the wiper blade,
The drive signal on the pressurizing side is output from the output terminal O1 of IC1.
In a normal state, the contact 16 moves to the section d as the slider 12 driven by the motor 14 moves. at the same time,
High level from output terminal O3 of IC1 (hereinafter referred to as H level)
Signal is output, and the input terminal 1 ▲ of the first timer unit 24a
Since ▼ becomes H level, an H level signal is output from the output terminal 1Q and a low level (hereinafter referred to as L level) signal is output from the output terminal 1. Since the input terminal 2 () of the second timer section 24b is at H level and the input terminal 2 is at H level, the output terminal 2Q outputs the L level signal and the output terminal 2 outputs the H level signal. Is output.

As described above, the contact 16 is generated by driving the motor 14.
When reaches the section e corresponding to the medium speed state from the section d, the position drive signal stops the motor drive signal from the output terminal O1 of the IC1 and the output signal of the output terminal O3 of the IC1 also changes from the H level to the L level. Returning to the level, the input terminal 1 (1) of the first timer section 24a becomes the L level. At this time, the first
Each state of both output terminals 1Q and 1 of the timer 24a is the input terminal 1 ▲ within a predetermined clock time t1 indicated by an imaginary line.
When ▼ becomes L level, it returns to the original state. Then, one output terminal 2Q of the second timer section 24b, which is an input signal to the input terminal I4 of IC3, remains at the L level and the other output terminal 2 remains at the H level. , The output terminal O2 remains as H level. Further, it is assumed that the H level signal from the output terminal 1 of the first timer section 24a is input to the input terminal I1 of the IC3 and the L level signal from the output terminal O3 of the IC1 is input to the input terminal I2 of the IC3. , The output terminal O1 of the IC3 is set to the H level, and the second timer section 24b does not enter the time counting start state.

In the right half of Fig. 5, the state at the time of abnormality is shown. Similarly to the above, the low speed running state changes to the medium speed running state, and the input of the middle speed signal drives the motor 14 from the output terminal O1 of IC1. Even if the signal is output, when the wiper arm 2 cannot be displaced due to foreign matter being caught in the link mechanism or the like of the wiper arm 2, the contact 16 does not move and the position signal in the state of the section c continues to be input to the IC1. Therefore, since the drive signal continues to be output from the output terminal O1 of IC1 to the motor 14 in order to displace the wiper arm 2 in the direction of moving the contact 16 to the section e, the output terminal O3 of IC1 remains at the H level. , The input terminal 1 of the first timer section 24a remains at H level.

The output terminal 1Q of the first timer section 24a becomes L level when the time is up due to the elapsed time t1, and the L level signal is input to the input terminal I7 of IC1.
The H-level signal from O3 is input to the input terminal I2 of IC3, and the H-level signal of the output terminal 1 is input to the input terminal I1 of IC3, so that the output terminal O1 of IC3 is set to the L level. The second timer unit 24b starts counting time. At this time, the output terminal 2 of the second timer unit 24b
Q becomes H level, the input terminal I8 of IC1 becomes H level, the drive signal is output with the output terminal O1 of IC1 set to H level, and the pressing force of the wiper blade 3 is applied to the motor 14 for a predetermined time t2. Drive in an increasing direction.

Then, when the time is up in the second timer section 24b due to the passage of a predetermined time t2, the output terminal O2 of the IC3 is set to L.
When a level signal is output and the input terminal I9 of the IC1 becomes the L level, the output terminals O1 and O2 of the IC1 are set to the L level, the drive signal is stopped, and the motor 14 is stopped. .

As described above, the movement of the contact 16 is completed within the time t1 of the first timer portion 24a in the normal state, but in the abnormal state in which the wiper arm 2 cannot be displaced, the position signal from the pressure sensor 17 does not displace even after the time t1 elapses. Therefore, it tries to continue driving the motor 14 until the vehicle speed signal and the position signal match, but the second timer unit 24b starts time measurement after the time-up of the first timer unit 24a, and during the time t2. The motor 14 only in the direction to increase the pressing force of the wiper blade 3.
The drive signal is continuously output to the motor 14 after the time t2 has elapsed.
Stop driving. Therefore, when the wiper arm 2 cannot be displaced and the drive signal is continuously output to the motor 14, the current is prevented from flowing unnecessarily to the motor 14 and an overcurrent is prevented, and the wiper blade 3 during running is prevented. It is possible to secure a sufficient wiping ability that can be applied to high-speed traveling by setting the pressing force of to a high state. In addition, when the above-mentioned processing at the time of abnormality is performed, the control circuit is not reset until the control circuit is put in the hold state and the ignition switch is turned off, for example, to prevent malfunction after occurrence of the abnormal state. There is.

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

In the second embodiment, the 2-bit vehicle speed signal from the vehicle speed signal generation circuit 25 is input to the input terminals I1 and I2 of the IC4 which is, for example, the 74HC85 as the main control unit of the control circuit. Further, the position signals by the same pressing position sensor 18 and contact 16 as in the above-mentioned embodiment are converted into 3-bit signals from the respective conductive patterns 23a-23c as in the above-mentioned embodiment. The conductive pattern 23a includes resistors R4 and R5 and a knot circuit NT1.
Is connected to one of the pair of input terminals of the exclusive OR circuit EX1 through this order. In addition, the conductive pattern 23b, through the resistors R6, R7 and the knot circuit NT2 in the same manner as above, the conductive pattern 23c through the resistors R8, R9 and the knot circuit NT3 in the same manner as described above, a pair of exclusive OR circuit EX2. Are connected to the input terminals of.
The output terminal of the exclusive OR circuit EX2 is connected to the other input terminal of the exclusive OR circuit EX1. The output terminal of the exclusive OR circuit EX1 is I
It is connected to I3 of I3 to I5 as the position signal input terminal of C4, the output terminal of the exclusive OR circuit EX2 is connected to the input terminal I4, and the output terminal of the knot circuit NT3 is connected to the input terminal I.
It is connected to 5 and a 3-bit position signal is input to IC4 as in the above embodiment.

The three output terminals O1 to O3 of the IC4 output H level signals in accordance with the result of comparison 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 vehicle speed signal, the output terminal O1 becomes H level, and when the vehicle speed signal and the position signal match, the output terminal O2 becomes H level and the position signal with respect to the vehicle speed signal. Is on the high voltage side, the output terminal O3 becomes H level.

The output terminal O1 is one of the three input terminals of the AND circuit AD1.
The output terminal of the AND circuit AD1 is connected to one of the pair of input terminals of the OR circuit OR1.
The output terminal of R1 is connected via a resistor R21 to the base of a transistor Tr1 whose emitter is grounded, which constitutes a pressurizing side drive circuit for driving the motor 14 in a direction to increase the pressing force of the wiper blade 3. The base and emitter of the transistor Tr1 are connected via a resistor R22, and the relay Ry1 is connected to the collector of the transistor Tr1 in the same configuration as in the above embodiment.

The output terminal O3 is one of the three input terminals of the AND circuit AD2.
The output terminal of the AND circuit AD2 is connected to one of the pair of input terminals of the NAND circuit ND1, and the output terminal of the NAND circuit ND1 is connected through the knot circuit NT5 and the resistor R23 in this order, and the wiper blade is connected. It is grounded to the base of a transistor Tr2 whose emitter is grounded, which constitutes a pressure reducing side drive circuit for driving the motor 14 in the direction of decreasing the pressing force of 3. Similarly to the above, the base and emitter of the transistor Tr2 are connected via the resistor R24, and the relay R is connected to the collector of the transistor Tr2 in the same configuration as the above embodiment.
y2 is connected, and the motor 14 is connected between the common terminals of both relays Ry1 and Ry2.

The output terminal O2 is connected via the knot circuit NT4 to the input terminal 1 ▲ ▼ of the first timer 26 that operates in the same manner as the first timer section 24a of the above-described embodiment, and also the OR circuit.
It is connected to one of a pair of input terminals of OR2. The output terminal of the OR circuit OR2 is connected via a resistor R25 to the input terminal 2 of a second timer 27 that operates in the same manner as the second timer section 24b of the above embodiment. The resistor R25 and the input terminal 2 are grounded via the capacitor C9.
The input terminal 1 of the first timer 26 is grounded, its output terminal 1Q is connected to one of the input terminals of the AND circuit AD2, and the output terminal 1 is connected to the OR circuit via a knot circuit NT6. It is connected to the other input terminal of OR2.

By the way, the output terminal of the exclusive OR circuit EX1 is connected to one of the three input terminals of the AND circuit AD3 via the knot circuit NT7, and the output terminal of the exclusive OR circuit EX2 is connected to the input terminal of the AND circuit AD3. The output terminal of the knot circuit NT3 is connected to the other one, and is connected to the remaining one of the input terminals of the AND circuit AD3. The output terminal of the AND circuit AD3 is connected to the input terminal 2 of the second timer 27 via the knot 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 terminal 2 is connected to the other input terminal of the NAND circuit ND1. The output terminal 2Q is connected to one of the pair of input terminals of the flip-flop circuit 28 as the operation prohibiting means via the resistor R26, and the output terminal 2 is connected to the other input terminal of the flip-flop circuit 28. There is. The resistor R26 and one terminal of the flip-flop circuit 28 are grounded via the capacitor C10.

The flip-flop circuit 28 is configured by combining three NAND gates as shown in the figure. The output terminal of the flip-flop circuit 28 has both AND circuits AD1 and AD2.
Are connected to the remaining input terminals respectively.

Next, the operating procedure of the above-described second embodiment will be described below with reference to the time chart of FIG. Similar to FIG. 5, in FIG. 7, the left half shows a time chart at the time of normal operation, and the right half shows a time chart at the time of abnormality.
Further, detailed description of the same parts as those in the above-mentioned embodiment will be omitted.

In a normal state, as in the above embodiment, the output terminals O1 and O2 of the IC4 return to their original states before the time is up due to the elapsed time t1 of the first timer 26. Since the output of the AND circuit AD1 becomes L level, the output of OR1 of the OR circuit also becomes L level, and the driving of the motor 14 is stopped. Therefore, as shown by the imaginary line in the figure, 1 ▲ ▼ before the first timer 26 times out.
Goes to the L level, its output terminal 1 goes to the H level, and the L level signal from the knot circuit NT6 is input to the OR circuit OR2. However, since the output terminal O2 of the IC4 is at the H level, the second timer 27 Since the H-level signal is input to the input terminal 2 of the second timer 27, the second timer 27 does not start timing.

When there is an abnormality, the pressed position sensor 18
Since the position signal of is not switched and remains at the output signal L level of the output terminal O2 of the IC4, the output signal of the output terminal 1 thereof becomes the H level when the first timer 26 times out, The second timer 27 starts the clock. In response to the start of the clock of the second timer 27, the output terminal 2Q thereof becomes H level, so that the relay Ry1 of the pressurizing side drive circuit is turned on and the pressing force of the wiper blade 2 is increased as in the above-mentioned embodiment. The motor 14 will continue to be driven to the side. Second
When the timer 27 times out, the output of the flip-flop circuit 28 becomes L level, so both AND circuits AD1, A
The output of D2 becomes L level, and relays Ry1 and R of both drive circuits
y2 is turned off and the driving of the motor 14 is stopped.

The second embodiment also has the same effect as the above-mentioned embodiment. That is, when 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 to measure the time and the motor 14 is moved in the direction to increase the pressing force of the wiper blade 3 within the time t2. Is driven to maintain the pressing force of the wiper blade 3 in a high pressure state, and then the driving of the motor 14 is stopped when the second timer 27 times out. Further, as in the above-described embodiment, the above state can be reset under conditions such as turning off the ignition switch.

In the second embodiment, at the time of high speed, the signal of the maximum pressing position becomes an L level signal via the knot circuit NT8 and is input to the input terminal 2 of the second timer 27.
That is, at the time of high speed, the wiper blade 3 is in the maximum pressed state, and it is not necessary to displace the wiper arm 2 in the direction to increase the pressing force in the time counting time t2.
Does not keep time.

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

[Effects of the Invention] According to the present invention, as described above, the means for increasing / decreasing the biasing force of the wiper arm can be operated within the first predetermined time by the first timer means in the normal state, but the first predetermined time If the wiper arm cannot be displaced and the pressing force corresponding to the vehicle speed cannot be obtained due to some abnormality by the time elapsed, the urging force is increased or decreased in the direction in which the urging force of the wiper arm is increased by the second timer means for the second predetermined time. By activating the means and then deactivating the means, the pressing force of the wiper blade can be made high and a sufficient wiping ability for high-speed traveling can be secured.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a vehicle speed sensitive pressure variable wiper device to which the present invention is applied. FIG. 2 is a longitudinal sectional view showing a main part 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 pressing position sensor of the present apparatus. FIG. 5 is a time chart showing the operating procedure of the first embodiment. FIG. 6 is a diagram showing the control circuit of the second embodiment. FIG. 7 is a time chart showing the operating 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 member, 9a ... … Slot 11 …… Coupling member, 12 …… Slider 12a …… Female thread, 13 …… Hook member 13a …… Hook pin, 14 …… Motor 15 …… Male screw, 16 …… Contact 17 …… Wiring board, 18… … Pressed position sensor 22 …… Vehicle speed signal generation circuit 22a ～ 23c …… Conductive pattern 24 …… Timer circuit, 24a …… First timer section 24b …… Second timer section, 25 …… Vehicle speed signal generation circuit 26 …… 1 timer section, 27 ...... second timer 28 ...... flip-flop circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Shirato 1268-1, Hirosawa-cho, Kiryu-shi, Gunma Prefecture Mitsuba Electric Manufacturing Co., Ltd. (56) Reference JP-A-1-186449 (JP, A) Open 62-238151 (JP, A) Open 63-105560 (JP, U) Open 63-154373 (JP, U)

Claims (1)

(57) [Claims] 1. A means for generating a force for urging a wiper arm in a direction of pressing a wiper blade against a glass surface, a means for increasing / decreasing the urging force, and a means for extracting a signal corresponding to the urging force. When the signal of the biasing force detecting means and the biasing force detecting means reaches a value corresponding to the changed vehicle speed, the biasing force increasing / decreasing means is operated so as to increase or decrease the biasing force according to the level of the vehicle speed. A vehicle speed responsive pressure variable wiper device having a control circuit for deactivating the urging force increasing / decreasing means, wherein the control circuit has the urging force within a first predetermined time from the start of operation of the urging force increasing / decreasing means. First timer means for enabling the increasing / decreasing means, and second timer means for enabling the biasing force increasing / decreasing means within a second predetermined time from the passage of the first predetermined time. , The first predetermined If the signal from the biasing force detecting means does not reach a value corresponding to the changed vehicle speed by the time elapsed, then the biasing force increasing / decreasing means is thereafter turned to the direction in which the biasing force increases for the second predetermined time. A vehicle speed responsive pressing variable wiper device, comprising: an operation prohibiting means for holding the operation state after the operation.