JPH02283551A - Control circuit of wiper for automobile - Google Patents

Abstract

PURPOSE:To carry out wiping in a scope other than the part where the wiping resistance is increased and to reduce the possibility of operating a circuit breaker, when the wiping resistance is increased, by starting a reversing device before a specific time passes, when an overload is detected on a motor by a detecting device. CONSTITUTION:At the power source terminals of contacts of relays, the first and the second lock detecting circuits 4A and 4B to detect the locking condition of a motor are inserted respectively, and the detected outputs of them are input to a relay instruction circuit 1. The relay instruction circuit 1 furnishes a clocking circuit 5, drives the clocking circuit 5 when a detected output is input to start the clocking, and gives an instruction to cut off the current feeding to a motor M2 to a winding control circuit 3 when the detected output is continued for the time exceeding a specific time 2T. The relay instruction circuit 1 gives an instruction to reverse the relay to the winding control circuit 3 while reserving the clocking time value of the clocking circuit 5, when the next cam signal does not reach from a cam signal circuit 2 in a time exceeding the time T being a half of the specific time 2T.

Description

[Detailed description of the invention] [Industrial application field] INDUSTRIAL APPLICATION This invention is utilized for the wiper for automobiles.

〔overview〕

The present invention provides a wiper blade control device for an automobile, which includes means for reversing the motor for each reciprocating operation of the wiper blade, in which one reversing operation is performed mechanically, and a means for interrupting motor current due to an overload. By reversing the rotation of the motor before the cut-off means is activated when the wiper is locked, the wiper operates even if the wiping range of the wiper blade is narrowed, thereby ensuring the driver's visibility as much as possible. It is.

[Conventional technology]

2. Description of the Related Art Wipers for automobiles are known in which the direction of a motor that drives the wiper blade is reversed every time the wiper blade makes one reciprocating motion.

As shown in FIG. 3(a), the motor M2 that drives the wiper WP by the reduction shaft R3 equipped with the cam CA has a
The direction of rotation is reversed by alternately applying currents in opposite directions from the motor power supply circuit MS. The cam CA has a cam position C1 and a cam position C2 located at a center angle α1 apart from the cam position C1, and the cam is configured to send signals to the cam contacts 1 and 2 at each position. When the control unit CP receives these signals, it reverses the motor power supply circuit and adjusts the cam CA to the center angle α.

Go back and forth between. Therefore, the first arm ARI attached to the tip of the reduction shaft R3 reciprocates between arm positions Ll and L2 corresponding to the cam positions CI and C2 so as to form a center angle α1. On the other hand, wiper shaft W
The respective tips of the second arm AR2 and the first arm ARI fixed to the PS are connected to the connecting rod C.
It is connected to both ends of L so as to be rotatable.

Therefore, as shown in FIG. 3(b), the first arm AR
At the arm position L13 of the second arm AR2 corresponding to arm position 3, which is the center arm position between arm positions Ll and L2 of arm position 1, the wiper axis W is mechanically unrelated to the reversal of motor M2.
PS is reversed. In this way, the wiping angle α2 of the wiper blade WP is the central angle α.

In addition, the wiper blade is reversed at wiper position Wl due to the reversal of the supply direction of the drive current of motor M2, and at wiper position W2, arms AR1 and AR2 are reversed.
It is mechanically reversed by a link mechanism between the connecting rod CL and the connecting rod CL.

In FIG. 4, the wiper blade WP performs a wiping operation on the glass surface 11. In the figure, the cam contact KO is the position taken when the wiper is stored in its storage position RP.

When the above-mentioned wiper is operating on such a glass surface 11, wiping resistance is applied to the wiper blade due to obstructions 12 such as snow scraped on the glass surface, and the load on the motor M2 increases rapidly. There are things to do. In such a case, to protect the wiper's electrical circuit, the relay box CRB is equipped with circuit breakers CBI and CB2 in the circuits through which the drive current of each relay's motor flows, and these circuit breakers are installed to detect when an overload has occurred. Additionally, when this overload continues beyond a predetermined time, the drive current to the motor is cut off.

[Problem to be solved by the invention]

However, it is not desirable for the driver to have the wiper stop. There is a demand for a wiper that can wipe most of the wiping angle range without any areas where such obstructions are attached.

Additionally, the inventors have discovered that when the obstruction is snow, for example, the wiper blade can be reversed to cause the obstruction to fall off.

In order to cope with such an operation, the present invention is designed to improve the driver's visibility by wiping the area excluding this area, for example, when an obstruction is attached and the wiping resistance of the wiper increases in that area. It is an object of the present invention to provide a control device for a wiper for an automobile, which can ensure the following and reduce the possibility that a circuit breaker will operate.

[Means to solve the problem]

The present invention includes a reversing means for reversing the rotational direction of the motor every cycle of the wiper blade movement, a detecting means for detecting that an overload has occurred on the motor, and a detection output of the detecting means exceeding a predetermined time. In a control circuit for an automobile wiper, the control circuit is equipped with a cutoff means that cuts off the current supplied to the motor when the current continues to be reversed before a predetermined time elapses when the detection means detects that an overload has occurred on the motor. The configuration includes means for activating the means.

[Effect]

When the wiper blade hits an obstruction and becomes locked, the direction of movement of the wiper blade is reversed before the current supply to the motor is cut off.

This greatly reduces the possibility that the wiper operation will stop due to obstructions. Furthermore, this attached obstruction can also be removed from the window glass.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

In this figure, the rotation direction of the motor M2 is reversed every cycle of the wiper blade operation (reciprocating around the center angle α2). As a means for this, cam CA and cam position CI
, C2 are provided with cam contacts 1 and K2.

When the cam contacts this cam contact and a signal is input to the control unit CP provided in the relay box CRB, the relay winding R
1 or R2 is activated, and the respective contact r1 or r2
will change. When the cam CA moves from the cam position Ct to C2 by the center angle α1 and contacts the cam contact point 2, and its output is input to the control unit CP, the control unit CP controls the winding R2 of the relay.
is energized, and the drive current for the motor M2 is manually applied from the contact r2 as shown by the arrow below, causing the motor M2 to rotate in the direction of the half-hour hand in the figure. However, at arm position 3 of the first arm ARI provided on the reduction shaft R3 coaxial with the cam CA, the wiper blade WP is reversed by the connecting rod CL.

Therefore, at the wiper position W1 shown in FIG. 1, the wiper blade WP is reversed by the reversal of the supply current of the drive current of the motor M2, and at the wiper position W2, the wiper blade WP is reversed by the link mechanism.

First and second lock detection circuits 4A and 4B are installed at the power terminals of the contacts of each relay to detect the locked state of the motor.
are inserted, and their detection outputs are manually input to the relay command circuit 1. The relay command circuit 1 is equipped with a clock circuit 5, and when the detection output is detected, it drives the clock circuit 5 to start timing, and when the detection output continues beyond the predetermined time 2T, it is supplied to the motor M2. The winding control circuit 3 is configured to give a command to the winding control circuit 3 to cut off the current flowing through the winding.

Here, the feature of the present invention is that if the next cam signal does not arrive from the cam signal circuit 2 within a time period exceeding 172 times T of the predetermined time period, the relay command circuit changes the time value measured by the timer circuit 5. While holding the winding control circuit 3.
This is where a command is given to reverse the relay.

In other words, when the wiper blade wipes away obstructions 12 such as snow stuck to the rear window 11 and an abnormal load is applied to the motor, the motor is forcibly reversed at a time T that is half the normal shutoff operation time. let

At this time, the surface of the wiper blade has already wiped away the obstruction, so the blade wipes without any abnormalities until the next reversal point, and at that reversal point it performs the normal reversal operation and clears the obstruction again. It reaches position 2 and is forcibly reversed by repeating the above operation.

In this way, the wiping operation between the reversal point and the obstruction, where a normal reversal operation is performed, can be continued. Moreover, by reversing the wiper blade, the obstruction itself can be removed.

If the wiper blade enters the obstruction 12 and the motor reverses, it immediately becomes locked, and if the measured time exceeds the predetermined time 2T, a cutoff operation is performed as in the conventional example, and the wiper circuit is shut off. will be preserved.

Note that in FIGS. 1, 3, and 4, for ease of explanation, the cam CA and the first arm AR1 are shown as separate worm gears WG, but in reality they are almost the same body. It has become.

〔Effect of the invention〕

As explained above, according to the present invention, when the wiper blade becomes inoperable due to an obstruction attached to the glass surface, by forcibly reversing the motor, the wiping angle is narrow (even if the wiper blade becomes inoperable). Since the operation continues, this has the effect of helping to secure the driver's field of view.Furthermore, since the present invention applies a force in the opposite direction to the obstruction, it has the effect of making the obstruction itself fall off.

[Brief explanation of drawings]

FIG. 1 is a control block configuration diagram of an embodiment of the present invention. FIG. 2 is a control flow chart of the embodiment shown in FIG. FIG. 3 is an explanatory diagram of wiper operation. FIG. 4 is a block diagram of a conventional example. 1... Relay command circuit, 2... Cam signal circuit, 3...
...Relay winding control circuit, 4A, 4B...first and second lock detection circuits, respectively, 5...timekeeping circuit,
ARI, AR2...first and second arms, CA/
...Cam, CB1, CB2...Circuit breaker,
CL...Connecting rod, 01-C3...Cam position, CP...Control unit, CRB...Relay box, K1
- to 2...cam contact, Ll-L3, Lit-Ll3.
...Arm position, M2...Motor, MS...Motor power supply circuit, R1, R2...Relay winding, rl, r2
... Relay contact, RP... Wiper blade storage position, R3... Deceleration shaft, Wl, W2... Wiper blade position, WG... Worm gear, WP... Wiper blade, WPS ...wiper shaft, WS...wiper switch.

Claims (1)

[Claims] 1. Reversing means for reversing the rotational direction of the motor every cycle of the wiper blade movement; detecting means for detecting occurrence of an overload on the motor; and a detection output of the detecting means. In a control circuit for an automobile wiper, which is equipped with a cutoff means for cutting off the current supplied to the motor when the current continues beyond a predetermined time, when the detecting means detects that an overload has occurred on the motor. A control circuit for an automobile wiper, comprising means for activating the reversing means before the predetermined time elapses.