JP2819515B2 - Variable pressure control method for wiper device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a method for controlling a pressing force variable of a wiper device.
In particular, the present invention relates to a pressing force variable control method for a wiper device of a type that changes the pressing force of a wiper blade against a glass surface according to the level of vehicle speed.

<Conventional technology> Generally, various vehicles are provided with a wiper device for wiping raindrops or the like attached to a glass surface of a window shield, but the wiper blade is easily lifted by running wind during high-speed running. Is known to be. Various structures are known to prevent this floating.For example, Japanese Patent Application Laid-Open No. 62-187636 discloses that a wiper arm is biased by a spring in a direction to increase a pressing force of a wiper blade against a glass surface, and a motor is used. There is disclosed an apparatus in which the spring is expanded and contracted by using a reciprocating lever to change the tension of the spring, so that the pressing force of the wiper blade is automatically changed according to the vehicle speed.

In such a pressing force variable structure, for example, a pressing force sensor capable of generating a signal value that changes according to the pressing force is provided in the wiper device, and the target value of the target pressing force according to the vehicle speed and the sensor The signal values are compared with each other, and when both values match, the pressing force increasing / decreasing means is stopped, and the above-mentioned stopped state is maintained while the vehicle speed is traveling at a substantially constant speed within a predetermined range. However, if the signal value from the pressing force sensor changes to an abnormal value for some reason during the stop state, it is determined that the target value has not been reached and the pressing force increasing / decreasing means is operated. It is possible.

<Problems to be Solved by the Invention> In view of the problems of the related art, a main object of the present invention is to maintain a pressing force on a glass surface of a wiper blade at a target pressing force according to a vehicle speed. It is another object of the present invention to provide a method of controlling the pressing force of a wiper device which is improved so as to preferably prevent a malfunction when the read signal value changes to an abnormal signal.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the object of the present invention is to increase or decrease the pressing force of the wiper blade against the glass surface in accordance with the vehicle speed by the pressing force increasing / decreasing means. Reading the generated signal value from a pressing force sensor capable of generating a signal value that changes in accordance with the increase or decrease of the pressing force, and detecting the vehicle speed. Setting a target pressing force set in accordance with the vehicle speed to a target value, activating the pressing force increasing / decreasing means until the generated signal value and the target value substantially match each other, Setting the pressing force increasing / decreasing means to a stop state when substantially coincides with each other, and writing the generated signal value at the time of the stop state to a stop memory; and reading the generated signal value during the stop state. The generated signal value A step of determining whether or not the generated signal value is not a normal value; and a step of, when it is determined that the generated signal value is not a normal value, replacing the value written in the stop memory with the read signal value instead of the generated signal value. This is achieved by providing a pressing force variable control method for a wiper device, comprising:

<Operation> In this way, when the target value of the pressing force according to the vehicle speed substantially matches the signal value of the pressing force sensor, the pressing force increasing / decreasing means is stopped, and the signal value in the stopped state is the pressing force. When the value changes to an abnormal value that does not belong to the normal signal value from the sensor, the value read at the time using the value written to the stop memory when entering the stop state is used as the read value at that time. Erroneous operation due to occurrence of an abnormal signal can be prevented without being affected by the above.

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

FIG. 1 schematically shows a wiper device to which the present invention is applied. As shown in FIG. 1, a wiper motor 2 mounted in a hood of an automobile has a wiper arm 2 via a link mechanism (not shown). Are connected to each other. 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 arrow A in the figure to wipe rain water or the like attached to the glass surface 4 of the window shield. ing.

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

A slider 12 is supported in the arm head 5 so as to reciprocate in the direction of arrow B in FIG.
A motor 14 is fixedly provided on the right rear side in the drawing of FIG. A male screw 15 is coaxially fixed to the drive shaft of the motor 14, and is formed with an axis in the sliding direction at the rear end of the slider 12, so that the screw 15 is screwed into the screw portion 12a. . A hook member 13 is fixed to the tip of the slider 12, and a hook pin 13 fixed to the tip of the hook member 13 is provided.
a is engaged with a slot 9 a formed in the free end of the lever member 9.

Therefore, the forward / reverse control of the motor 14 as the pressing force increasing / decreasing means by the control circuit 20 described later can
12 reciprocates in the direction of arrow B in the figure, and the slot 9a is guided by the hook pin 13a, and the lever member 9 is moved to the arrow C in the figure.
Reciprocating in the direction of. Then, the connecting member 11
The coil spring 8 is expanded and contracted through the opening, so that the urging force of the wiper arm 2 can be adjusted, and the glass surface 4 of the wiper blade 3 can be adjusted.
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 the conductive patterns 19a to 19c formed on the wiring board 17 and shown in FIG. The contact 16 slides against the coil spring 8
A signal value corresponding to the tension of the wiper blade 3 via the wiper arm 2 is input to the control circuit 20 as a 3-bit signal that changes according to the contact state of the contact 16. Thus, the pressing force sensor 18 for detecting the signal value corresponding to the pressing force of the wiper blade 3 is configured.

The control circuit 20 receives a vehicle speed pulse signal from a vehicle speed sensor 21. The control circuit 20 sets a target pressing force for each predetermined vehicle speed width, for example, and sets the target pressing force and the pressing force. A control signal for rotating the motor 14 in the normal and reverse directions is generated by comparing the signal from the pressure sensor 18 with the control signal.

As shown in FIG. 3, three conductive patterns 19a to 19c are formed on the wiring board 17 in parallel with each other. Each free end of the contact 16 formed in the shape of a comb tooth divided into three so as to correspond to each of the conductive patterns 19a to 19c moves on the corresponding conductive patterns 19a to 19c with the displacement of the slider 12. And reciprocate while sliding in the direction indicated by arrow D in the figure. The contact 16 is grounded.
The conductive patterns 19a to 19c in contact with the contact 16 can be grounded to generate a 3-bit digital signal.

The pressing force of the wiper blade 3 is increased or decreased by a predetermined amount according to the width of each section a to g shown in FIG. 4 depending on the contact position of the contact 16 with the conductive patterns 19a to 19c. Bits are digitalized. A state where the contact 16 is not in contact with the conductive patterns 19a to 19c is represented by 1 and a state where the contact 16 is in contact is represented by 0, which is the stop position of the first-stage wiper arm 2 corresponding to the minimum pressing force. It is 111 in the section a, 011 in the next moving section b, 001 in the section c which is the stop position of the second step, 101 in the next moving section d,
It is 100 in the section e, which is the stop position of the third step, 000 in the next movement section f, and 010 in the section g, which is the stop position of the fourth step corresponding to the maximum pressing force.

FIG. 4 is a diagram showing a flowchart of control based on the present invention. In step ST1, the pressing force of the wiper blade 3, that is, the sensor signal value PNEW consisting of the aforementioned three bits of the contact 16 is input. In the next step ST2,
The sensor signal value PNEW is written to the position memory as the read value NOWP. In the next step ST3, a predetermined number of pulses that increase or decrease according to the level of the vehicle speed are counted, and the vehicle speed V calculated based on the count time is detected.
In ST4, a stop position P (V) corresponding to a pressing force determined according to the vehicle speed V from a preset time table is set as a target value PTAG.

Then, in step ST5, the sensor signal value PNEW is compared with the target value PTAG.
Then, the motor 14 is stopped, and the process proceeds to step ST7. In this step ST7, it is determined whether or not the first flag FLAG1 set in the next step ST8 is set (1 is input), and if the first flag FLAG1 is not set, that is, from the operating state. When the motor enters the stop state, ST
At 8, the sensor signal value PNEW when entering the stop state
Is written to the stop position memory OLDP, and the first flag FLAG
Set 1 (enter 1).

In step ST5, the sensor signal value PNEW is compared with the target value PTAG and they do not match, or in step ST7, FLAG1
When the motor is standing, that is, when the vehicle once enters the motor stop state and is in the middle of the stop state, or when step ST8 has elapsed, the process proceeds to the next step ST9. In step ST9, it is determined whether or not the read value NOWP is a preset regular value. In the case of the present embodiment, the generation position of the pressing force and each passing position are divided into the above-mentioned seven stages by the eight-stage bit string signal obtained by three bits, and the normal value is the seven three-bit signals. Is one of If a value corresponding to one of these regular values is recorded in the read value NOWP, the process proceeds to step ST10,
In step ST10, control is performed to increase or decrease the pressing force by rotating the motor 14 forward or backward so that the read value NOWP matches the target value.

In the sensor signal value PNEW, the same signal as the remaining one (not a regular value) of the above-described three-bit eight-stage bit string signal is
There is a possibility that it may occur due to some cause. If the abnormal signal is read to the read value NOWP, the above step ST
The process proceeds from step 9 to step ST11. If it is determined in step ST11 that the motor is stopped, the process proceeds to step ST12.
In ST12, the second flag FLAG2 is set (input 1).
Then, in step ST13, the value written in the stop position memory OLDP in step ST8 is read as the read value NOWP.
Substitute for

If it is determined in step ST11 that the motor is not stopped (the control for increasing or decreasing the pressing force toward the target value PTAG is performed), or if steps ST12 and ST13 have been performed, the process proceeds to step ST14 and proceeds to step ST14. Here, it is determined whether or not the second flag FLAG2 is set (1 is input). If the second flag FLAG2 is not set, that is, if the motor is operating, the above flow is repeated.
In step ST14, if the second flag FLAG2 is set, that is, if an abnormal signal is generated while the motor is stopped, the process returns to step ST9 to continuously monitor whether an abnormal signal is generated. Hereinafter, the above flow is repeated.

In the present embodiment, a case using a 3-bit signal has been described.
The present invention is not limited to the number of bits, and is applicable to a case where a signal of 2 bits or more is used and some unused portions of the bit signal are generated. This is effective when there is a possibility that a signal having the same value as the unused portion may be generated as a sensor signal. Further, the present invention is not limited to a digital signal, and can be applied to a case where a sensor signal exceeding the input voltage range of the sensor can be generated even in the case of an analog signal.

[Effect of the Invention] According to the present invention, as described above, when an abnormal pressing force signal that cannot be recognized as a value corresponding to the increase or decrease in the pressing force is generated while the operation of the control for increasing or decreasing the pressing force of the wiper blade is stopped. Since it is possible to suitably prevent the abnormal control of the increase and decrease of the pressing force from being started, it is possible to improve the reliability of the pressing force variable control for generating the pressing force on the glass surface of the wiper blade.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a wiper device to which the present invention is applied. FIG. 2 is a sectional view showing a main part of the wiper device. FIG. 3 is an explanatory diagram showing a detecting means of the wiper device. FIG. 4 is a flowchart of the control based on the present invention. DESCRIPTION OF SYMBOLS 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 Connecting member 12 Slider 12a Female thread 13 Hook member 13a Hook pin 14 Motor 15 Screw 16 Contact 17 Wiring board 18 …… Pressing force sensors 19a to 19c …… Conductive pattern 20 …… Control circuit, 21 …… Vehicle speed sensor

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masashi Nagata 1-2681, Hirosawa-cho, Kiryu-shi, Gunma Inside Mitsuba Electric Works, Ltd. (72) Susumu Watanabe 1-268-1, Hirosawa-cho, Kiryu-shi, Gunma Inside Mitsuba Electric Manufacturing Co., Ltd. (56) References Shokai Sho 63-154372 (JP, U) Shokai Sho 61-68952 (JP, U)

Claims (1)

(57) [Claims] 1. A variable pressing force control method for a wiper device of a type in which a pressing force on a glass surface of a wiper blade is increased or decreased in accordance with a level of a vehicle speed by a pressing force increasing / decreasing means. Reading the generated signal value from the pressing force sensor that can generate a signal value that changes
Detecting a vehicle speed, setting a target pressing force set according to the vehicle speed to a target value, and activating the pressing force increasing / decreasing unit until the generated signal value and the target value substantially match each other. And a step of setting the pressing force increasing / decreasing means to a stop state when the two values substantially match each other, and a step of writing the generated signal value at the time of the stop state to a stop memory; A step of determining whether or not the generated signal value read during the stop state is a normal value; and, when the generated signal value is determined to be not a normal value, the value written to the stop memory. And a step of using said read value instead of the generated signal value.