JPH04126644A - Wiper - Google Patents

Abstract

PURPOSE:To lessen number of parts of a wiper driving system and to reduce cost by connecting a configuration memory alloy actuator to an oscillation arm supporting a wiper blade in a freely oscillating manner and, causing the wiper blade to make a reciprocating motion by means of controlling the electric current. CONSTITUTION:When a light switch is turned on and a head light 20 lits, a configuration memory alloy actuator 7 generates heat by electrification as a rain drop sensor turns on detecting rain drops. The configuration memory alloy actuator 7 then deforms its configuration from that at a low temperature indicated by a solid line to that at a high temperature indicated by a virtual line and a hook portion 9 of the other end displaces to an oscillation direction outgoing side 14 of an oscillation arm 2 causing a wiper blade 5 to make a wiping motion of the head light 20 going toward the oscillation direction outgoing side 14. When the hook portion 9 departs from a contact member 16 and an electrification heat circuit is cut off, heat generation of the configuration memory alloy actuator 7 stops and causes the wiper blade 5 make a wiping motion of the head light 20 going toward the opposite direction, that is, an oscillation direction returning side 12.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a wiper for wiping a glass surface of a vehicle or the like.

[Prior Art] Vehicles such as automobiles are equipped with wipers for wiping glass surfaces such as front windows, rear windows, headlights, and side mirrors. The wiper usually has a wiper plate that supports the blade rubber, which is swingably supported by a swinging arm, and a motor is swingably connected to the swinging arm via a swinging link mechanism to drive the motor. As a result, the swing arm swings back and forth via the swing link mechanism, and the wiper blade supported by the swing arm wipes the glass surface. [Problems to be Solved by the Invention] However, the above-mentioned conventional wiper has a drawback that the cost is high because a large number of mechanical parts such as motors and link mechanisms are used in the drive system. In view of the above-mentioned circumstances, it is an object of the present invention to provide a wiper that can reduce costs by reducing the number of parts in the drive system. [Means for Solving the Problems] The present invention includes a shape memory alloy actuator in a swinging arm that swingably supports a wiper blade, which is memorized to change the swinging direction of the swinging arm due to temperature changes. The present invention relates to a wiper characterized in that the shape memory alloy actuator is arranged in an energization heating circuit that can supply and interrupt current. [Operation] When the shape memory alloy actuator is energized by the energization heating circuit, the shape memory alloy actuator generates heat, reaches a high temperature, and deforms. This deformation causes the swinging arm to swing, causing the wiper blade to perform a wiping action. When the wiper play 1 performs a wiping operation, the current in the energizing heating circuit is cut off. Then, the shape memory alloy actuator stops generating heat,
Thereafter, when the temperature of the shape memory alloy actuator decreases due to heat radiation or the like, the shape memory alloy actuator returns to its original shape and is pulled back in the opposite direction to the wiper plate. Thereafter, by repeating the above operation, the wiper plate performs a continuous wiping operation. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings.
' Figures 1 to 5 show an embodiment of the present invention. A swinging arm 2 whose intermediate portion is swingably supported by a shaft l protruding from a fixed member (not shown) is provided, and a blade rubber 4 having a large width dimension 3 is supported at the upper end of the swinging arm 2. Install wiper plate 5. One end of the band-shaped shape memory alloy actuator 7 is fixed to the fixing member 6 using a bolt 8, and a hook portion 9 formed by bending the other end of the shape memory alloy actuator 7 is attached to the lower end of the swing arm 2, so that the swing arm 2 can swing. The arm 2 is locked so as not to be restrained in the longitudinal direction 10 of the shape memory alloy actuator 7. When the shape memory alloy actuator 7 is at a low temperature, the other end or the return side 12 in the swing direction of the swing arm 2 (the shape memory alloy actuator tuff length direction 10
and a direction perpendicular to the width direction 11), and the hook portion 9 is twisted in the direction of the arrow I3 about the length direction 10, so that the other end becomes the shape shown in FIG. 2 when the temperature is high. As shown by the imaginary line, it is displaced to the forward side I4 in the swing direction opposite to the case of the solid line, and the hook portion 9 is moved in the direction of the arrow ■
5 in a twisted form. A contact member I6 is disposed so as to be able to contact the hook portion 9 at the position of the hook portion 9 of the shape memory alloy actuator 7 at a low temperature, and the wiper play 'f- is caused by the hook portion 9 of the shape memory alloy actuator 7 and the contact member I6. 17. A lighting circuit 21 includes a power source 18, a light switch I9, and a headlight 20, and a midpoint 22 between the light switch 9 of the lighting circuit 2I and the headlight 20, and a midpoint 23 between the headlight 20 and the power source 1B. During this time, the wiper switch 17 and the raindrop sensor 24, which turns on when raindrops are detected, are connected to form an energization heating circuit 25. The wiper having the above configuration is installed on the glass surface of the headlight 20, for example, as shown in FIG. Next, the operation will be explained. When the light switch 9 is turned on, current flows through the lighting circuit 21 and the headlight 20 is turned on. If it is not raining when the headlights 20 are turned on, the raindrop sensor 24 does not detect raindrops and is kept OFF, so that no current flows through the energizing heating circuit 25 and the wiper does not operate. On the other hand, if it is raining, the raindrop sensor 24 detects raindrops and turns on, and current flows through the energization heating circuit 25 to operate the wiper as will be described later. That is, when a current flows through the current heating circuit 25, the shape memory alloy actuator 7 of the wiper switch 17 provided in the middle generates heat due to the current and its own resistance. Then, the shape memory alloy actuator 7 becomes hot and deforms from the low-temperature configuration shown by the solid line in FIG. 2 to the high-temperature configuration shown by the phantom line in FIG. Since it is displaced to the going side 14, the swinging arm 2 swings, causing the wiper blade 5 to perform a wiping operation of the headlight 20 toward the going side 14 in the swinging direction. When the hook portion 9 at the other end of the shape memory alloy actuator 7 is displaced toward the forward side 14 in the swinging direction in this manner, the hook portion 9 separates from the contact member 16 and cuts off the current in the energization heating circuit 25. Then, the shape memory alloy actuator 7 stops generating heat, or is forcibly cooled down by the wind that the vehicle receives while driving, and gradually lowers its temperature, changing from the high temperature state shown by the imaginary line in FIG. Returning to the low temperature state as shown by the solid line, the hook portion 9 at the other end is displaced to the return side 12 in the swinging direction of the swinging arm 2, so that the swinging arm 2 is swung and the wiper plate 5 is The wiping operation of the headlight 20 toward the return side 12 in the opposite swing direction is caused. In this way, when the shape memory alloy actuator 7 returns to its low-temperature state, the wiper switch 17 is turned on again, and the above operation is repeated to continuously wipe the headlight 20. Since the shape memory alloy actuator 7 has a large output per unit weight, it is possible to sufficiently drive the wiper. In addition, by supporting the blade rubber 4 having a large width dimension 3 with the wiper blade 5 and fixing the wiper blade 5 to the tip of the swinging arm 2, the blade rubber 4 can be attached to the glass surface, which is necessary when wiping the headlight 20. The pressing force is controlled by the elastic force of the blade rubber 4 itself and the wiper blade 5.
This can be ensured by the elastic force of the swing arm 2.
The structure of the wiper itself can be simplified. FIG. 6 shows another embodiment of the present invention, which is stored to contract at high temperatures, and after contracting at high temperatures, does not return to its original expanded state even when the temperature is lowered again, that is, at low temperatures. Spring-like shape memory alloy actuator 2 that cannot memorize its shape
6, the spring-like shape memory alloy actuator 2
6 between the swinging arm 2 and the fixed member 28 on the swinging direction forward side 1
A bias spring 27 is attached to the return side 12 in the swing direction between the swing arm 2 and the fixed member 29, and has an elastic force smaller than the deformation force that acts on the shape memory alloy actuator 26 when the temperature is high. The configuration is substantially the same as that of the embodiment described above except that it is connected so as to be biased. With such a configuration, when a current is passed through the current heating circuit 25, the spring-like shape memory alloy actuator 2
6 generates heat, becomes high temperature, and contracts, swinging the swinging arm 2 toward the forward side 14 in the swinging direction and causing the wiper blade 5 to perform a wiping action. Further, when the swing arm 2 swings toward the forward side 14 in the swing direction and the wiper switch 17 is turned off and the current in the energizing heating circuit 25 stops, the temperature of the shape memory alloy actuator 2B decreases, and the shape at low temperature cannot be memorized. Since the shape memory alloy actuator 26 has a property that the deformation force becomes weaker as the temperature decreases, when the deformation force of the shape memory alloy actuator 26 decreases and becomes smaller than the elastic force of the bias spring 27, the bias spring 27 Due to the elastic force, the contracted shape memory alloy actuator 26 is extended, and the swing arm 2 swings toward the return side 12 in the swing direction, returning the wiper blade 5 to its original state while wiping the headlight 20. . Thereafter, the wiper blade 5 swings back and forth to continuously wipe the glass surface of the headlight 20. It should be noted that the wiper of the present invention is not limited to the above-described embodiment, and the wiper switch may not be provided in the shape memory alloy actuator itself, but may be provided separately, or may be provided in a location other than the headlight. It goes without saying that various modifications may be made without departing from the spirit of the present invention. [Effects of the Invention] As explained above, according to the wiper of the present invention, the structure can be greatly simplified by using the shape memory alloy actuator, and as a result, it is possible to achieve cost reduction. This can produce an excellent effect.

[Brief explanation of drawings]

FIG. 1 is an overall perspective view of one embodiment of the present invention, and FIG. 2 is a perspective view of an embodiment of the present invention.
Figure 3 is an enlarged view of the hook part of the shape memory alloy actuator in Figure 2, Figure 4 is a circuit diagram of the energization heating circuit, Figure 5 is the FIG. 6 is a perspective view of another embodiment of the present invention. In the figure, 2 is a swing arm, 5 is a wiper plate, 7.26
25 represents a shape memory alloy actuator, and 25 represents an energized heating circuit.

Claims (1)

[Claims] 1) Connect a shape memory alloy actuator that is memorized to change the swing direction of the swing arm due to temperature changes to the swing arm that swingably supports the wiper blade, and connect the shape memory alloy actuator to the swing arm that swingably supports the wiper blade. A wiper characterized in that it is disposed in an energizing heating circuit that can conduct and interrupt energization.