JPS61211151A - Arm pressure variable wiper corresponding to car speed - Google Patents

Abstract

PURPOSE:To prevent the floating of a wiper blade at high speed without increasing wiper wiping noise and wiper motor load at low speed by automatically switching the arm pressure that presses the wiper blade to a windowpane according to the car speed. CONSTITUTION:A car speed sensor generates pulse signals and send them to a control unit. In addition, if the voltage that is proportional to the car speed exceeds the standard voltage, the control unit applies heating voltage to a positive temperature characteristic heater 35. Then, since the positive temperature characteristic heater 35 generates heat and a spring 24 made of shape storage alloys is heated, this spring 24 tries to return to the original state. As a result, the second link 22 rotates around a pin 21 and the first link 20 rotates around a pin 19 clockwise by the pin 23 of the second link 22. Consequently, since a pulling spring 16 that presses a wiper blade 11 to a windowpane is extended and the arm pressure is increased, the floating of the wiper blade can be prevented at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wiper for a vehicle, and more particularly to a variable arm pressure wiper in which the pressing force of a wiper blade against a window glass is variable.

(Prior Art) Conventionally, when a vehicle travels at high speed, a problem arises in that the wind generated by the vehicle generates a lift force on the wiper, causing the wiper to float above the window glass surface and obstruct forward visibility. When this phenomenon occurs, especially when driving at high speed during rain, it is extremely dangerous because it not only obstructs forward visibility but also makes it impossible to wipe the window glass. In order to prevent this phenomenon, it is sufficient to increase the force with which the wiper blade presses against the window glass surface, that is, the arm pressure, but if the arm pressure is constantly increased, the life of the wiper blade rubber will be shortened and the wiper Problems such as increased wiping noise and increased load on the wiper motor occur.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and its purpose is to ensure that the window glass does not float even when driving at high speed, and to wipe the window glass reliably even when driving at high speed during rain. To provide a wiper for a vehicle, which can secure forward visibility, without increasing wiper wiping noise and load on a wiper motor, and without shortening the life of wiper blade rubber.

(Example) Next, the present invention will be explained based on FIGS. 1, 2, and 3 of the accompanying drawings.

In FIG. 1, reference numeral 10 denotes a rubber blade that comes into direct contact with the window glass of the vehicle, and the rubber blade 10 is fixed to a blade 11, which is connected to the arm piece 1.
2 with rivets 13. The arm piece 12 is fixed to the retainer 14 by a rivet 15, and a tension spring 16 that acts to press the wiper blade rubber 1o against the window glass is locked at the end of the arm piece 12. The retainer 14 is rotatably attached to the wiper arm head 18 by a pin 17.

A first link 20 is mounted on the wiper arm head 18 so as to be rotatable around the bin 19. The other end of the tension spring 16 is locked to one end of the first link 20, and the other end of the tension spring 16 is fixed to one end of the first link 20. Similarly, the pin 23 of a single-shaped second link 22, which is rotatably mounted on the wiper arm head 18 around the pin 21, is engaged. One end of a shape memory alloy tension spring 24 is locked to the other end of the second link 22 . The other end of the shape memory alloy tension spring 24 is connected to the wiper arm head 18
The second link 22 and the bin 2
Tension is applied to rotate it around 1. The spring 24 made of a shape memory alloy is stretched between the bottle 25 and the end of the second link 22 after being deformed transversely to a pitch larger than the original winding pitch. . Roughly, a heating device, that is, a positive temperature characteristic heater (P, T, C, heater) is installed so as to surround this shape memory alloy spring 24.
35 are arranged. A control device 26 is connected to the positive temperature characteristic heater 35, and the control device 26 includes a vehicle speed sensor that detects the speed of the vehicle and generates a pulse signal proportional to the vehicle speed, as shown in FIGS. 2 and 3. -27, and a control unit 28 that applies voltage to the positive temperature characteristic heater 35 in response to a pulse signal. The vehicle speed sensor 27 is a rotating body having a magnetic material on its circumference, and includes a rotor 29 that rotates in proportion to the rotation of the wheels, and a magnetic pickup 3 that generates a pulse signal due to changes in magnetic flux caused by the rotation of the rotor 29.
Consists of 0. The control unit 28 includes an amplifier 31 that amplifies the pulse signal, a frequency-voltage converter 32 that converts the pulse signal into an analog voltage, and compares the converted voltage with a base*voltage corresponding to the set vehicle speed. A comparator 33 generates a voltage for heating the positive temperature characteristic heater 35 if the voltage is equal to or higher than the reference voltage;
and an amplifier 34 for amplifying the heating voltage from 3 to the voltage necessary for heating the positive temperature characteristic heater 35.

Next, the action will be explained.

The vehicle speed sensor 27 generates a pulse signal in proportion to the vehicle speed and sends the pulse signal to the control unit 28. The control unit 28 compares a reference voltage corresponding to a predetermined vehicle speed with a voltage proportional to the vehicle speed, and applies a heating voltage to the positive temperature characteristic heater 35 if the voltage proportional to the vehicle speed is higher than the reference voltage. do. When a voltage is applied, the positive temperature characteristic heater 35 generates heat and heats the shape memory alloy spring 24. When the shape memory alloy spring 24 is heated, it attempts to return to its original state before deformation.

As a result, the second link 22 rotates around the bin 21 as shown by the dashed line in FIG. 1, and the first link 20 rotates clockwise around the bin 19 by the bin 23 of the second link 22. move. As a result, the tension spring 16, which acts to press the wiper blade against the window glass, is expanded, the arm pressure increases, and the wiper is prevented from floating at high speeds.

When the vehicle shifts to low speed running, the voltage generated by the pulse signal proportional to the vehicle speed becomes less than the reference voltage, so the control unit 28 no longer applies voltage to the positive temperature characteristic heater 35. As a result, the positive temperature characteristic heater 35 cools down,
The shape memory alloy tension spring 24 is also no longer heated. When the wiper blade is no longer heated, the shape memory alloy spring 24 is pulled and deformed by the tension spring 16, which acts to press the wiper blade against the window glass, returning to the state before heating. Therefore,
Since the arm pressure returns to its original state, the wiper wiping noise at low speeds and the load on the wiper motor do not increase.

FIG. 4 shows a modification of the present invention in which a shape memory alloy tension spring is stretched between a pin 25 provided on the wiper arm head 18 and a wiper blade suppression tension spring 16. The link device consisting of the first link and the second link in the embodiment shown in is omitted.

(Effects of the Invention) According to the present invention, the arm pressure that presses the wiper blade against the window glass is automatically switched in accordance with the vehicle speed.
To provide a wiper that does not increase wiper wiping noise and load on a wiper motor at low speeds, and prevents the wiper blade from lifting up at high speeds and reliably wipes a window glass.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a wiper according to an embodiment of the present invention. FIG. 2 is a schematic diagram of the wiper of the present invention mounted on an automobile. FIG. 3 is a block diagram of the control device of the present invention. FIG. 4 is a sectional view of a wiper according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Wiper blade, 16... Pressing tension spring, 24... Shape memory alloy tension spring, 26... Control device, 35... Heating device (positive temperature characteristic heater).

Claims (3)

[Claims] (1) One end of a pressing tension spring that acts to press the wiper blade against the window glass is locked to the end of the arm piece, the other end is locked to one end of the link device provided on the wiper arm head, and the shape After a tension spring made of a memory alloy is deformed by a predetermined amount, a heating device is placed between the other end of the link device and the wiper arm head, and a heating device that heats the tension spring made of a shape memory alloy is connected to the shape memory alloy. An alloy tension spring is provided surrounding the heating device, and a control device is connected to the heating device to apply a predetermined voltage to the heating device when the vehicle speed exceeds a predetermined speed, so that when the vehicle speed exceeds the predetermined speed. A variable arm pressure wiper corresponding to vehicle speed, characterized in that the tension spring made of a shape memory alloy is contracted by heating to change the mounting length of the pressure spring, thereby switching the pressure force of the wiper arm. (2) The heating device is a positive temperature characteristic heater (P.T.C.
The variable arm pressure wiper corresponding to vehicle speed according to claim 1, which is a heater). (3) The control device includes a vehicle speed sensor that detects vehicle speed and generates a pulse signal according to the speed, and applies a predetermined voltage to the heating device when the pulse signal from the vehicle speed sensor exceeds a predetermined value. A variable arm pressure wiper corresponding to vehicle speed according to claim 1, comprising a control unit for applying voltage.