KR960005617B1 - Back mirror operating devices by shape memory alloy - Google Patents

Abstract

The device consists of shape memory alloys(30),(31),(32),(33) having free end(F2) and fixing end(S1) fixed in the cases(20),(21), heating units(40),(41),(42),(43) heating the shape memory alloys(30),(31),(32),(33) over a critical temperature, regulating units(50),(51),(52),(53) which regulate the heat from heating units(40),(41),(42),(43), sliding blocks(60),(61),(62),(63), fixed to free end(F) of the shape memory alloys(30),(31),(32),(33), guide rails(70),(71),(72),(73) which guide the movement of shape memory alloys(30),(31),(32),(33) within a distance, power supplying units(80),(90) which transmit power to rear mirror housing(23) of a car by transforming non-rotational movement into rotational movement of sliding blocks(60),(61),(62),(63), stoppers(100),(101),(102),(103),(104),(105),(106),(107) folding and unfolding the housing of rear mirror, and rear mirror receiving room(27) located outside panel(25).

Description

Car rear view mirror driving device of shape memory alloy drive system

1 is a schematic view showing an embodiment of a vehicle rearview mirror folding drive apparatus according to the present invention.

Figure 2 is a schematic diagram showing another embodiment of a vehicle rearview mirror folding drive apparatus according to the present invention.

3 is a partial cross-sectional view showing the structure of a rearview mirror housing and a rearview mirror storage chamber according to the present invention.

Figure 4 is a plan view of a vehicle showing a state in which the automobile rearview mirror folding drive apparatus according to the present invention is installed.

* Explanation of symbols for main parts of the drawings

20, 21: Case 23: rearview mirror housing

25: outer panel 27: rearview mirror storage room

30, 31, 32, 33: shape memory alloy 40, 41, 42, 43: heating means

50, 51, 52, 53: control means 60, 61, 62, 63: sliding block

70, 71, 72, 73: guide rails 80, 90: power transmission means

81, 91, 92: belt pulley 82: belt groove

83, 93: belt 84, 94: pulley shaft

100, 101, 102, 103, 104, 105, 106, 107: stopper

F: Free end S: Fixed end

VR1, VR2, VR3, VR4: Variable resistor

SW1, SW2, SW3, SW4: Push-on switch

M1, M2, M3, M4: Moving contact piece S1, S2, S3, S4: Fixed contact piece

The present invention relates to a vehicle rearview mirror folding driving device of a shape memory alloy driving method, and more particularly, to a shape memory alloy driving method of folding a rearview mirror of an automobile using a shape memory effect of a shape memory alloy. The present invention relates to an automobile rearview mirror folding drive device.

In general, the vehicle is provided in the rear of the driver's seat in order to secure the rear clock, and is equipped with a rearview mirror with reflectors located on both sides of the vehicle.

However, the reflector of the rearview mirror must have a certain lateral width so that the driver can easily identify the object reflected thereon.

Therefore, the rearview mirror is usually protruded slightly from the side of the vehicle.

Therefore, the overall width of the car is widened, and when such a car is parked in a narrow road, it obstructs the traffic of the vehicle passing through it.

Thus, in the related art, a rearview mirror that manually folds and straightens with a human hand has been invented.

However, such a rearview mirror has a very uncomfortable problem because the user has to fold and stretch it by hand.

The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to automatically fold and unfold the rearview mirror of a car by using the shape memory effect of the shape memory alloy.

In order to achieve the object of the present invention, one end of both ends is a fixed end and the other end is fixed to one side in the case, respectively, the other end is a free end free movement and a plurality of shapes alternating the shape recovered and deformed shape alternately Memory alloy; A plurality of heating means for heating each of the shape memory alloys above a critical temperature causing reverse transformation; A plurality of control means for arbitrarily controlling each of the heat generated by the heating means; A plurality of sliding blocks fastened to the free ends of each of the shape memory alloys and moved together with the movement of the shape memory alloys; A plurality of guide rails slid or cloud-coupled with the sliding block and fixed in the case such that the sliding blocks are guided with a certain movement area; Power transmission means for converting the non-rotational movement of the sliding block moving according to the deformation of the shape memory alloy into rotational movement to transmit power to the rearview mirror housing of the vehicle; The rearview mirror housing or an object interlocking with the rearview mirror housing is fixedly installed on an object supporting the rearview mirror housing or an object interlocking with the rearview mirror housing so that the rearview mirror housing is unfolded. Two stoppers to allow them to be folded or folded; When the rearview mirror housing is folded, a rearview mirror storage driving apparatus of a shape memory alloy driving system is provided, which is formed of a rearview mirror housing formed in a recess on an exterior panel of a vehicle for accommodating the rearview mirror housing.

Hereinafter, an embodiment of a vehicle rearview mirror folding drive apparatus of a shape memory alloy driving method according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are schematic diagrams showing one embodiment and another embodiment of the shape rear view mirror driving apparatus of the shape memory alloy driving method according to the present invention, and as shown therein, one side in the cases 20 and 21. Each of the shape memory alloys 30, 31, 32, and 33 each having a shape-recovered shape and a modified shape are alternately installed so that one end is fixed and the other end is free. (30) (31) (32) (33) a plurality of heating means (40) (41) (42) (43) which respectively heats above a critical temperature causing reverse transformation And a plurality of control means (50), (51), (52) and (53) for arbitrarily controlling the heat generated by the heating means (40), (41), (42) and (43), respectively. A plurality of sliding blocks 60, 61, 62, and 63 are respectively fastened to the free ends F of the shape memory alloys 30, 31, 32, and 33 to form the shape memory alloys 30 ( 31) (32) (33) movement According to the sliding blocks 60, 61, 62, 63 to move together, a plurality of guide rails so that each of the sliding blocks 60, 61, 62, 63 have a certain movement area ( 70) (71) (72) (3) are slid or rolled with the sliding blocks (60) (61) (62) (63), respectively, and fixedly installed in the cases (20) (21), and the shape memory The non-rotational movements of the sliding blocks 60, 61, 62, and 63 moving in accordance with the deformation of the alloys 30, 31, 32, and 33 are converted into rotational movements to the rearview mirror housing 23 of the vehicle. A stopper (100) (101) (102) (103) (104) (105) having power transmission means (80) (90) for transmitting power and allowing the rearview mirror housing (23) to be unfolded or folded. An object interlocking with the rearview mirror housing 23 or at the same time so that the rearview mirror housing 23 or an object interworking with the rearview mirror housing 23 or the same with each other is positioned at two predetermined positions on the movement area where the motion can be moved. The rearview mirror housing 27 for accommodating the rearview mirror housing 23 when the rearview mirror housing 23 is folded is formed on the outer panel 25 of the vehicle. .

All of the shape memory alloys 30, 31, 32, 33, and intermittent means 50, 51, 52, 53, sliding blocks 60, 61, 62, 63, all in plural. In addition, the guide rails 70, 71, 72, and 73 are constituted of two guide rails, as shown in the two illustrated examples.

The shape memory alloys 30 and 31 in the example shown in the first drawing attached to Figure 1, when all heated above the critical temperature to cause a reverse transformation while shrinking than the length before heating, the second attached drawing different from this In the example shown in the figure, when all were heated above the critical temperature, it consisted of shape memory alloys 32 and 33 which generate | occur | produce a reverse transformation while extending | stretching more than the length before heating.

The shape memory alloys 30, 31, 32 and 33 are configured in the form of coils wound in spiral wires, and the shape or cross-sectional shape may be arbitrarily set and is not limited thereto.

The heating means (40) (41) (42) (43) are two different embodiments of each of the shape memory alloys (30), (31), (32) and (33). The shape memory alloys 30, 31 and 31 were formed by giving a voltage difference at both ends to generate heat of resistance according to the electric resistance inherent in the shape memory alloys 30, 31, 32 and 33. 32) (33) used battery power of an automobile, for example.

In addition, by limiting the current supplied to the shape memory alloys 40, 41, 42, 43, excessive resistance to the variable memory in series with the shape memory alloys 40, 41, 42, 43 VR1), VR2, VR3, and VR4 are respectively connected, and in some cases, a current limit value may be calculated in advance, and a fixed resistor according to the value may be connected.

The control means 50 and 51 are energized when pressed to supply or cut off power to each of the shape memory alloys 30 and 31 in the example shown in FIG. 1 as shown in FIG. 1 and automatically open when the external force is removed. A plurality of push-on switches (SW1) (SW2) to be connected in series with the shape memory alloys (30) and (31), the movable contact piece to the free end (F) of the shape memory alloys (30) and (31) A plurality of (M1) (M2) is connected, but buried so as to be exposed on one side of the sliding block 60, 61, and each of the shape memory alloys (30) (31) is stretched only when the movable contact piece ( A plurality of stationary contact pieces S1 and S2 in electrical connection with M1 and M2 were provided in the case 20.

In addition, in the illustrated example shown in FIG. 2, a plurality of push-on switches SW3 are energized when pressed to supply or cut off power to the shape memory alloys 32 and 33, and are automatically opened when external force is removed. (SW4) is connected in series with each of the shape memory alloys 32 and 33, as in the above-described example, and the movable contact piece (the free end F) of the shape memory alloys 32 and 33 is connected. A plurality of M3) (M4) is connected, but is embedded so as to be exposed on one side of the sliding block (62) (63) and the shape memory alloys (32) and (33) as opposed to the above-described example only when the minimum shrinkage A plurality of stationary contact pieces S3 and S4 in electrical connection with the moving contact pieces M3 and M4 were provided in the case 21.

The moving contact pieces M1, M2, M3 and M4 and the fixed contact pieces S1, S2, S3 and S4 in the above two embodiments are notified due to lack of contact pressure when they are in contact with each other. In order to minimize the probability, it is preferable that one is configured to have only one of the two to have elastic force in the direction facing each other.

On the other hand, the power transmission means (80, 90) is a belt driving method, both as shown in Figure 1 and 2 of the accompanying drawings, it is a method using only one pulley in the illustration of FIG. Is wrong to use 2 pulleys.

In the illustrated example of FIG. 1, the belt pulley 81 is disposed on one side of the case 20 so as to be rotatable, and the belt 83 comes into contact with the belt groove 82 of the belt pulley 81. Both ends of the tension is installed in the free end or the sliding block 60, 61 of the shape memory alloy (30) and (31) to alternately stretch or contract, respectively, and the belt pulley (81) as shown in FIG. The interlocking pulley shaft 84 protrudes out of the case 20 to be fixedly coupled to the rearview mirror housing 23.

In the example shown in FIG. 2, two belt pulleys 91 and 92 are rotated on one side of the case 21 with an interaxial centerline at least parallel to the axial centerline of the guide rails 72 and 73. And the two belt pulleys (91) and (92) are tensioned with the belt (93) of the caterpillar type, and the belt (93) receives an opposing force when the belt (93) moves in the forward and reverse directions. The sliding blocks 62 and 63 are fixedly installed on the tension or relaxation side of the belt), and as shown in FIG. 3, the pulley side of the two belt pulleys 91 and 92 interlocks with one of the belt pulleys 91. (94) protruded out of the case 21 and fixedly coupled to the rearview mirror housing (23).

As in the above two embodiments, the belts 83, 93, and belt pulleys 81, 91, 92 are formed of timing belts and timing pulleys or V-belt and V-belt pulley wires with teeth formed on contact surfaces thereof. It can consist of a wire or a wire pulley.

Meanwhile, the guide rails 70 and 71 in the example shown in FIG. 1 are straight rails, each of which is fixedly installed on the case 20 by passing through fastening bolts 28 through both ends of the guide rails. 100, 101, 102, and 103 were also provided at predetermined positions at both ends of the guide rails 70 and 71, respectively.

In addition, the guide rails 72 and 73 in the example shown in FIG. 2 are also straight rails similar to those of the above-described guide rails 721 and 73, but the coil-shaped memory alloys are formed on the guide rails 72 and 73. (32) and (33) were used, so a round rod-type polishing rod was used, and both ends thereof were installed to be spaced apart from the case 21 by a predetermined distance.

That is, the guide rails 72, 73 are clamped by using the supporters 75, 76, 77, and 78 that protrude forward in the drawing from both ends of the round bar guide rails 72 and 73. The shape memory alloys 32 and 33 in the form of coils inserted therein are not separated from the case 21 so as not to contact the case 21. The guide rails 72 and 73 are formed of an electrical insulator. Shorting of the memory alloys 32 and 33 can be prevented.

In addition, the Teflon system having a low friction coefficient so that the insulation is formed only on the perturbation surfaces of the guide rails 72 and 73 and the sliding blocks 62 and 63 without forming the guide rails 72 and 73 as an insulator. The resin may be configured to apply a predetermined thickness on the contact surface between the two resins or to sandwich the insulating layer while insulating.

In the example shown in FIG. 2, the stoppers 104, 105, 106, and 107 are placed on the case 21, respectively, so that the stoppers 104, 105, 106, and 107 are positioned on the movement area in which the sliding blocks 62 and 63 move. Installed.

Then, the rear view mirror housing 27 formed in the recess on the outer panel 25 of the vehicle for accommodating when the rear view mirror housing 23 is folded has a bottom surface of the rear view mirror storage chamber 27 as shown in FIG. A through hole 29a is formed on the housing 29, and the casings 20 and 21 are external panels so that the pulley shafts 84 and 94 protrude into the rearview mirror accommodating chamber 27 through the through holes 29a. (25) It is fixedly installed on the inner bottom surface, and a spacer (W) is fitted to the pulley shafts (84) and (94) protruding into the rearview mirror storage chamber (27), and a spline hole (SP) is provided on the bottom surface of the rearview mirror housing (23). Form and press-fit the pulley shafts 84 and 94 to extend the shape memory alloys 30, 31, 32 and 33 in the cases 20 and 21 located inside the outer panel 25. As the pulley shafts 84 and 94 rotate by the contracting action, the rearview mirror housing 23 is accommodated or exited therefrom.

In the figure, reference numeral BT denotes a battery power source of an automobile.

The operation and effect of the present invention as described above will be described.

First, in the embodiment in which the apparatus of the present invention is configured as shown in FIG. 1, when the rearview mirror housing 23 is unfolded and the rearview mirror housing 23 is to be folded and stored in the rearview mirror storage chamber 27, as shown in FIG. When the push-on switch SW2 is pressed, the movable contact piece M2 and the fixed contact piece S2 are in contact with each other from the battery power source BT of the vehicle through the variable resistor VR2 for current limiting. A closed circuit leading to the memory alloy 31 is formed.

At this time, a potential difference is generated at both ends of the shape memory alloy 31, and a current flows through the shape memory alloy 31 so that the shape memory alloy 31 generates heat according to the resistance inherent in the shape memory alloy 31. Done.

When the temperature at which the shape memory alloy 31 generates heat after the above operation exceeds the critical temperature, the shape memory alloy 31 undergoes reverse transformation and shrinks in a very short time to its original contracted shape. The sliding block 61 and the belt 83, which are fastened to the free end F of the memory alloy 31, are also dragged together to move at the same time. The belt pulley 81 is also drawn by the belt 83 in the direction of arrow A in the figure. Is rotated.

Even if the "ON" operation of the push-on switch SW2 is extremely short, the above operation occurs at the instant.

That is, even if the user turns ON the push-on switch SW2 for only a short time and releases the finger, the heat generation temperature of the shape memory alloy 31 will cause a reverse transformation already above the critical temperature.

The shape memory alloy 31 which is contracted while finding the shape memorized as described above is stopped by the stopper 103 with the sliding block 61 to stop the contracted movement, and the belt 83 is pulled out. When the sliding block 60 on the opposite side and the shape memory alloy 30 already in the contracted state are also pulled together, the shape memory alloy 30 on the opposite side becomes an elongated shape instead of the original memorized shape.

If the belt pulley 81 rotated as described above is fastened in a direction in which the rearview mirror housing 23 is accommodated, the rearview mirror housing 23 is accommodated in the rearview mirror accommodation chamber 27.

In addition, since the guide rails 70 and 71 are all straight rails, the sliding blocks 60 and 61 are all linearly guided and do not interfere with each other.

When the rear view mirror housing 23 folded in the above state is to be pushed to the "ON" state by pressing the push-on switch SW1 different from the first time, this time the shape different from the first shape memory alloy 31 The current flows to the memory alloy 30, so that only the shape memory alloy 30 generates heat, and when the temperature exceeds the critical temperature, the shape memory alloy 30 is instantaneously restored to the originally stored contracted shape. The sliding block 60 and the belt 83 are pulled while rotating the belt pulley 81 in the arrow B direction.

As in the beginning, the shape memory alloy 31 on the opposite side is forcibly stretched by the deformation of the other shape memory alloy 30 from the original memorized shape.

In addition, when the shape memory alloy 30 deforms to some extent, the sliding block 60 is caught by the stopper 101, so that the position of the rearview mirror housing 23 that is unfolded while the movement is blocked can be made constant.

On the other hand, in the embodiment of the present invention is configured as shown in Figure 2 attached to the rearview mirror housing 23 is unfolded in this state when the rearview mirror housing 23 should be folded and stored in the rearview mirror storage chamber 27 shown in FIG. As described above, when the push-on switch SW3 is pressed, the moving contact piece M3 and the fixed contact piece S3 in which the current limit is in contact with each other through the variable resistor VR3 from the battery power source BT of the vehicle. A closed circuit is formed through the shape memory alloy 32 through.

At this time, a potential difference occurs at both ends of the shape memory alloy 32, and a current flows through the shape memory alloy 32, so that the shape memory alloy 32 generates heat according to the resistance inherent in the shape memory alloy 32. Done.

After the above-described action, the shape memory alloy 32 generates heat in the instant when the temperature of the heat generation exceeds the critical temperature, the shape memory alloy 32 undergoes inverse transformation, and is deformed in a very short time. The sliding block 62 and the belt 93, which are fastened to the free end F of the memory alloy 32, are also dragged together to move simultaneously, and the two belt pulleys 91 and 92 are also drawn by the belt 93. It is rotated in the arrow C direction in a figure.

Even if the above "ON" operation of the push-on switch SW3 is extremely short, the above operation occurs at the instant.

That is, even if the user “ON” the push-on switch SW3 for a short time and releases the finger, the exothermic temperature of the shape memory alloy 32 will cause a reverse transformation already above the critical temperature.

The shape memory alloy 32 which is elongated while finding the shape memorized as described above is stopped by the stopper 104 with the sliding block 62 and the elongation movement is stopped, and the belt 93 is pulled out. When the sliding block 63 on the opposite side and the shape memory alloy 33 which has already been extended are also pulled together, the shape memory alloy 33 on the opposite side becomes a contracted shape instead of the original memorized shape.

If the two belt pulleys 91 and 92 that rotate as described above are fastened in a direction in which the rearview mirror housing 23 is accommodated, the rearview mirror housing 23 is accommodated in the rearview mirror accommodation chamber 27.

In addition, since the guide rails 72 and 73 are all straight rails, the sliding blocks 62 and 63 are all linearly guided and do not cause interference with each other, and the coil-shaped shape memory alloys inserted therein It will also function to guide the stretching movement of (32) (33).

When the rearview mirror housing 23 is folded in the above state, when the push-on switch SW4 different from the first is pressed to the "ON" state, this time, the shape memory different from the first shape memory alloy 33 is different. An electric current flows in the alloy 33, so that only the shape memory alloy 33 generates heat. When the temperature exceeds a critical temperature, the shape memory alloy 33 is instantaneously restored to the original shape, which is remembered. The sliding block 63 and the belt 93 are pulled to rotate the two belt pulleys 91 and 92 in the direction of the arrow.

Like the first time, the shape memory alloy 32 on the opposite side is forcibly contracted by the deformation of the other shape memory alloy 33 from the original memorized shape.

In addition, since the shape memory alloy 33 deforms to some extent, the sliding block 63 is caught by the stopper 106, so that the position of the rearview mirror housing 23 that is unfolded while the movement is blocked can be made constant.

As described above, the present invention is simply operated by pressing a switch installed in a vehicle, using a battery power source or other power source to restore the stored shape while causing reverse transformation when the temperature exceeds the critical temperature of the shape memory alloy as an actuator. The rearview mirror can be folded vertically or laterally, which makes it convenient to fold and unfold the rearview mirror. Moreover, the shape memory effect of low-cost shape memory alloys, which are relatively inexpensive and easy to repair and replace, are not expensive electric motors or other actuators. It is possible to realize the automation of rearview mirror folding at a low cost since it is a driving source. Furthermore, since the resilience and response speed of the shape memory alloy are considerably fast, the operation of the switch can be controlled by just touching the finger with the finger. In addition to the control circuits, Since the failure rate is achieved which also can talk also it lowered effect.

Claims (9)

One end of both ends is a fixed end (S1) is fixed to one side in the case 20, 21 and the other end is a free end (F2) free to move, alternating shape and deformed shape alternately A plurality of shape memory alloys 30, 31, 32 and 33; A plurality of heating means (40) (41) (42) (43) for heating each of the shape memory alloys (30) (31) (32) (33) above a critical temperature causing reverse transformation; A plurality of control means (50) (51) (52) (53) for arbitrarily controlling the heat of each of the heating means (40) (41) (42) (43); The plurality of shape memory alloys 30, 31, 32, 33 are respectively fastened to the free end (F) of the plurality of shape memory alloys 30, 31, 32, 33 move together in accordance with the movement of the Two sliding blocks 60, 61, 62 and 63; The sliding blocks 60, 61, 62 and 63 are slid or cloud-coupled with the sliding blocks 60, 61, 62 and 63, respectively, so that the sliding blocks 60, 61, 62 and 63 are guided with a certain movement area. A plurality of guide rails (70) (71) (72) (3) fixedly installed in (20) (21); The rear view mirror housing of the vehicle by converting the non-rotational movement of the sliding blocks 60, 61, 62, 63 moving in accordance with the deformation of each shape memory alloy (30) (31) (32) (33) Power transmission means (80) (90) for transmitting power to (23); The rearview mirror housing 23 or an object interlocking with the rearview mirror housing 23 or an object interlocking with the rearview mirror housing 23 is fixedly installed on an object supporting the rearview mirror housing 23 or an object interlocking with the rearview mirror housing 23 at the same position. A plurality of stoppers (100) (101) (102) (103) (104) (105) (106) (107) to allow the rearview mirror housing (23) to be unfolded or folded; Shape-memory alloy drive type vehicle characterized in that the rearview mirror housing 23 is composed of a rearview mirror accommodating chamber 27 recessed on the outer panel 25 of the vehicle for accommodating the rearview mirror housing 23 when folded Rearview mirror folding drive. The method of claim 1, wherein all of the plurality of shape memory alloys 30, 31, 32, 33 are contracted to cause reverse transformation while shrinking than the length before heating when the plurality of shape memory alloys 30, 31, 32, 33 are heated above the critical temperature. Automotive rearview mirror folding drive of shape memory alloy drive system. The guide according to claim 1, wherein all of the plurality of shape memory alloys (30, 31, 32, 33) are extended to cause reverse transformation while being longer than the length before heating if they are heated above a critical temperature of the plurality of shape memory alloys. An automobile rearview mirror folding drive device of a shape memory alloy driving method, characterized in that it is loosely fitted on a rail (72) (73). According to claim 1, wherein the control means 50, 51 is a plurality of energized when pressed to supply or cut off power to each of the shape memory alloys (30) (31) is opened automatically when removing the external force Push-on switches SW1 and SW2; A plurality of moving contact pieces (M1) (M2) which are exposed on one side of the sliding blocks (60) and (61) and are connected to free ends (F) of the shape memory alloys (30) and (31), respectively; Only a plurality of fixed contact pieces S1 and S2 installed in the case 20 to make an electrical connection with the movable contact pieces M1 and M2 only when the shape memory alloys 30 and 31 are fully extended. Vehicle rearview mirror folding drive device of the shape memory alloy drive method characterized in that consisting of. The method of claim 1, wherein the control means 52, 53 is energized when pressed to supply or cut off power to each of the shape memory alloys (32) (33), a plurality of automatically opened when removing the external force Four push-on switches SW3 and SW4; A movable contact piece (M3) (M4) which is exposed on one side of the sliding block (62) (63) and connected to the free end (F) of the shape memory alloy (32) (33), respectively; A plurality of fixed contact pieces (S3) (S4) provided in the case (21) to make an electrical connection state with the moving contact piece (M3) (M4) only when the shape memory alloy (32) (33) is contracted to a minimum Vehicle rearview mirror folding drive device of the shape memory alloy drive method characterized in that consisting of. According to claim 1, wherein the power transmission means 80 is configured to rotate the belt pulley 81 on one side in the case 20 to rotate, the belt 83 in the belt groove 82 of the belt pulley 81 The both ends of the belt 83 are tensioned at the free ends F of the shape memory alloys 30 and 31 or the sliding blocks 60 and 61, respectively, when the belts 83 are in contact with each other. The shape memory alloy driving method is installed, characterized in that the belt drive system configured to be fixed to the rear view mirror housing 23 by protruding the pulley shaft 84 in conjunction with the belt pulley 81 to the outside of the case 20. Car rearview mirror folding drive. The belt pulley (91) according to claim 1, wherein the power transmission means (90) has an interaxial centerline at least parallel to an axial centerline of the guide rails (72) (73) on one side of the case (21). (92) are laid out, and the two belt pulleys (91) and (92) are tensioned with an endless belt (93), so that the belt (93) receives a force that is reflected when each moves in the forward and reverse directions. A pulley fixed to the tension side and the relaxation side of the belt 93, the sliding blocks 62 and 63 respectively being interlocked with the belt pulley 91 of one of the two belt pulleys 91 and 92; The rear view mirror folding drive device of the shape memory alloy drive method characterized in that the shaft (94) protrudes out of the case (21) to be fixedly coupled to the rearview mirror housing (23). The shape memory according to claim 1, wherein the heating means (40) (41) (42) (43) all have a voltage difference across both of the shape memory alloys (30) (31) (32) (33). An automobile rearview mirror folding drive apparatus of a driving method, characterized in that the heat of resistance is generated according to the electric resistance inherently possessed by the alloys (30) (31) (32) (33). 9. The shape memory alloys (30) (31) (32) (33) of claim 8, wherein the shape memory alloys (30) (31) (32) (33) are used to limit the current supplied to the shape memory alloys (30) (31) (32) (33). And a variable resistance (VR1) (VR2) (VR3) and (VR4) respectively provided in series with each other.