JP3043961B2 - Electric retractable door mirror control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric retractable door mirror control device for electrically moving a door mirror to a retracted state or an upright state, and more particularly to an electric retractable door mirror for controlling driving means of the door mirror using a latching relay. Related to a control device.

[0002]

2. Description of the Related Art Generally, a door mirror is mounted so as to protrude from a side of a vehicle body. In this case, a protruding door mirror may be an obstacle in a garage or the like, and therefore, a retractable electric retractable door mirror has been proposed. FIG. 9 is an exploded perspective view of an electric retractable door mirror disclosed in Japanese Patent Application Laid-Open No. 2-290754. The electric retractable door mirror has a pivot shaft 50, a mirror housing 59, a clutch mechanism 60 and the like. I have. The pivot shaft 50 has a flange portion 52 and a shaft portion 51, and the flange portion 52 is provided with a pair of arc-shaped grooves 54 and 55. A bracket 57 is provided on the bottom of the mirror housing 59, and the bottom surface forms a rotation surface 58.

A ball 56 is fitted into a hemispherical concave portion (not shown) provided on a rotating surface 58, and has arc-shaped grooves 54, provided on a fixing surface 53 of a flange portion 52.
55 and the mirror housing 5 with respect to the pivot shaft 50.
9 is rotatable. The mirror housing 5
The rotation of 9 is performed by driving means such as a motor (not shown) and gears.

FIG. 10 is a plan view taken in the direction of arrow II in FIG. 9. In FIG. 10, an arc 61 indicates the trajectory of the ball 56 moving on the fixed surface 53 of the pivot 50. Also,
FIG. 11 shows a cross section developed along arrow III. In the figure, reference numerals 56a, 56b, and 56c denote the positions of the ball 56 when the mirror housing 59 is located at the standing position, the storage position, and the retracted position, respectively. In addition, the step portion 62 of the arc-shaped grooves 54 and 55 has a step H,
6 is restricted. The rotation mechanism of the mirror housing 59 will be described with reference to these drawings. When the motor is driven to rotate the mirror housing 59 to the retracted position, the ball 56 approaches the position 56b. When the position 56e is reached, the power supply to the motor is cut off. At this time, since the gears and the like have a backlash, the movement of the mirror housing 59 does not stop at the same time as the power supply to the motor, but continues to rotate by inertia, and the ball 56 contacts the step portion 62 and stops at the position 56b. .

The same applies to the standing position. When the ball 56 reaches the position 56d, the power supply to the motor is stopped, and the ball 56 is rotated by inertia and stopped at the position 56a. When the door mirror comes into contact with the obstacle, the ball 56 rides over the step 62 and is located at the evacuation position due to the contact force with the obstacle. To position the mirror housing 59 in the upright position or the like, for example, a mechanical switch method (limit switch, plate contact switch, etc.)
There is. In addition, a method of interrupting the circuit by increasing the current when the motor is locked by utilizing the characteristics of the PTC element (actually open flat 4-7)
6196) are also disclosed. It is also known to control the motor by detecting the rotation of the motor with a sensor such as a photoreflector or a magnetic sensitive element.

[0006]

However, the above-described method has the following problems. In the method using the PTC element, there is a large time lag from the occurrence of overload to the motor until the temperature of the PTC element reaches a predetermined temperature. Therefore,
During this time, power is continuously supplied to the motor. As a result, the ball 56 is separated from the bottoms of the arc-shaped grooves 54 and 55 so as to get over the step 62, and the mirror housing 5
There is a problem that 9 is tilted.

[0007] In addition, this time lag is such that the mirror stops rotating when an emergency occurs, for example, when the arm or finger is pinched by the mirror while the mirror is rotating. Is supplied and the driving force for the rotation of the mirror is applied, so that the arms and fingers may be pressed, leading to a serious injury. In the method of detecting the rotation of the motor, there is a concern that dust, dirt, and the like may adhere to the sensor portion and cause a malfunction. In addition, in order to reflect the signal from the sensor on the control signal of the motor, a complicated electronic circuit such as an amplifier circuit and a drive circuit is required, which causes a problem that the cost is increased. Therefore, an object of the present invention is to provide a control device for an electric retractable door mirror capable of solving the above-mentioned problem with a simple circuit.

[0008]

In order to achieve the above object, in a control apparatus for an electric retractable door mirror, a mirror body provided with a mirror is turned to a standing position and a storage position by driving means. A switch circuit for switching the polarity of a current flowing through the driving means, a latching relay having a coil connected in series to the driving means, and a shunt connected in parallel to the coil so as to rotate the head in the standing position direction or the storage position direction. With resistance,
When the mirror body is rotated to reach the standing position or the retracted position and the driving means is locked, a shunt voltage generated by the shunt resistor increases, and the shunt voltage becomes higher than a sensing voltage of the latching relay. And a control circuit for shutting off the power supply to the driving means when the latching relay is activated and holding the cutoff state until the switch circuit is switched.

For example, when the resistance value of the shunt resistor is 5Ω
Hereinafter, it is preferably set to 0.5 to 2Ω.

[0010] The sensing voltage of the latching relay is 5
V or less, preferably 0.5 to 2 V.

The NTC is connected in series with the latching relay.
A thermistor is connected, and a capacitor is connected in parallel with the thermistor, so that inrush current for starting the motor generated when the switch circuit is turned on is reduced.

The control circuit may include two diodes connected in parallel with their forward directions reversed so that one of the diodes is forward-biased regardless of the direction of the current, and two diodes connected in series to the coil. And these are connected in parallel with the shunt resistor.

Further, the control circuit has a pair of zener diodes connected in a reverse direction to each other with the latching relay interposed therebetween, and the shunt resistor is connected in parallel with the circuit.

[0014]

The operation of the present invention will be described with reference to FIG. The latching relay used in the present invention has a structure in which a coil is wound around a core such as iron and a permanent magnet is attached to a COM terminal. In general, a relay operates with a magnetic field, so that a predetermined current needs to flow. The same applies to the latching relay, except that the operating current value is determined by the magnetic force between the permanent magnet and the core. It has the feature that its state is maintained.

Although the latching relay is a current active element, the operation start current corresponds to the operation start voltage because the coil resistance is constant. In the present specification, this is called a sensing voltage. In this specification, a state in which the permanent magnet and the core are attached to each other is referred to as magnetic adhesion (or a magnetic adhesion state). On the other hand, the motor has a property that a large drive current flows in an abnormal load state as compared with when the motor is rotating normally.

The operating principle of the present invention will be described with reference to FIG. Now, the door mirror is in the upright position (FIG. 1A), and the door mirror is in the storage position (FIG. 1A).
Considering the case of (b)), it is assumed that a power supply, a motor, and the like are connected as shown in FIG. In the state shown in FIG. 1A, the driver turns on the switch to retract the door mirror and supplies current to the coil. The current flows in the order of power supply → coil → NC terminal → COM terminal → motor → power supply. This current generates a magnetic field in the direction of releasing the magnetically attached state between the portion A of the core and the permanent magnet, but the magnetic field is insufficient in magnitude to release the magnetically attached state. On the other hand, since this current is sufficient to normally rotate the motor, the mirror rotates in the storage position direction (R direction). At this time, the lock mechanism (stopper) provided at the upright position does not function for rotation of the mirror in the storage position direction. Therefore, the door mirror rotates toward the storage position while the connection state between the COM terminal and the NC terminal is maintained.

Then, the rotation of the door mirror is locked by a lock mechanism provided at the storage position, and a large current (lock current) flows with the lock. Since the magnetic field generated by this lock current is large enough to release the magnetically attached state in FIG. 1A, the latching relay operates, and the permanent magnet changes from the state in FIG. 1A to the state in FIG.
It changes to the state of. That is, the permanent magnet leaves the portion A of the core and magnetically attaches to the portion B. Therefore, the connection state between the COM terminal and the NC terminal is released, the power supply to the motor is cut off, and the rotation of the door mirror stops. In addition, when changing from the storage position to the standing position, the above-described reverse procedure is performed.

When a motor and a coil are connected in series and a current flows, there is a problem that a driving current fluctuates due to uneven rotation of the motor or the like and a latching relay malfunctions. Therefore, a shunt resistor is connected in parallel with the coil to bypass the current. At this time, if the shunt resistance value is too large, the drive current is limited, so that this resistance value needs to be reduced. On the other hand, the sensing voltage of the relay is generally about 1 V in commercial products, and cannot be arbitrarily reduced.

From such a viewpoint, the shunt voltage is set to be lower than the sense voltage when the motor is rotating normally, and the shunt voltage is set to be higher than the sense voltage when the motor is locked. Specifically, the sensing voltage and the shunt resistor are used by being appropriately set and used, but a preferred sensing voltage is 5 V or less,
More preferably, it is 0.5 to 2V. The shunt resistance is preferably 5Ω or less, and more preferably 0.5 to 2Ω.

The start of the motor is performed by turning on the switch circuit. However, at this time, a rush current for starting the motor flows, and the latching relay may malfunction. Therefore, a capacitor is connected in parallel with the coil, and an NTC thermistor is connected in series with the coil.
This capacitor absorbs the inrush current and alleviates the rise of the shunt voltage, thereby preventing malfunction of the latching relay. In addition, the NTC thermistor has a property that the resistance value is high at low temperatures (several to several tens of ohms), and when the temperature is increased by Joule heat or the like, the resistance value drops rapidly (1 ohm or less). Therefore, immediately before energizing the motor,
Since the temperature of the NTC thermistor is low (high resistance), a large voltage drop occurs in the NTC thermistor. Therefore, a large voltage is not applied to the latching relay, and malfunction can be prevented. Thereafter, the resistance value decreases as described above. In the above description, the malfunction prevention is completely performed by using both the NTC thermistor and the capacitor, but they may be used individually.

[0021]

An embodiment of the present invention will be described with reference to the drawings. FIG.
FIG. 3 shows the control device of the electric retractable door mirror in the standby state to the storage position, and FIG. 3 shows the control device in the standby state to the standing position. Note that the electric retractable door mirror (hereinafter, appropriately referred to as a mirror) may take an intermediate position (retreat position) other than the retracted position and the standing position described above. That is, the mirror is deviated from the standing position or the storage position by being pushed from the outside, and is located between the standing position and the storage position, and is also moved from the standing position in the direction opposite to the storage position. This is the case when it is shifted.

The controller 4 of the electric retractable door mirror according to the present invention comprises a switch circuit 2 and a control circuit 3. The switch circuit 2 is a two-circuit switch, and can supply a current of opposite polarity to the motor by switching. The switch circuit 2 is installed around a driver's seat such as an instrument panel in a vehicle compartment and is operated by a driver. Of course, the switch circuit 2 may be constituted by an electronic circuit. The control circuit 3 includes a latching relay R having a coil RC.
Y, two diodes D1 and D2 connected to the relay terminals a and b of the latching relay RY, a shunt resistor R connected in parallel to the coil RC, and an NT connected in series to these.
It is composed of a C thermistor NTC and a condenser C. The control circuit 3 can be incorporated in the mirror housing or in the same unit as the switch circuit 2. Note that a motor M, which is one of the driving means, is connected to the relay terminals a and b.

Next, the operation of the control device 4 will be described. At this time, the rotation of the motor when the mirror rotates in the direction from the storage position to the standing position is called standing rotation, and conversely, the rotation of the motor when the mirror rotates in the direction from the standing position to the storage position is the storage rotation. I will call it.

(1) When the mirror is in the upright position In this state, the control circuit 4 is in the state shown in FIG. 2, the relay terminal a is in the "closed state", and the relay terminal b is in the "open state". Therefore, the switch circuit 2 is connected to the storage side (storage position side) A
1 and A2, when a positive voltage is applied to the COM terminal 1 and a negative voltage is applied to the COM terminal 2, the current flowing through the NTC thermistor NTC passes through a parallel circuit of the shunt resistor R and the coil RC, and passes through the relay terminal a and the motor. M and diode D2
And flows to the COM terminal 2. As a result, the motor M rotates for storage, and the mirror rotates in the storage direction. When the storage position is reached, the rotation is mechanically stopped and the motor current increases (this is called a lock current). As a result, when the shunt voltage generated at both ends of the shunt resistor R exceeds a predetermined value (the sensing voltage of the latching relay), the latching relay RY operates and the relay contacts a and b are brought into the state shown in FIG.

In the present embodiment, the shunt resistance value is set to 2Ω, the lock current is set to 1 amp, and the latching relay RY is set to operate when the shunt voltage reaches 2V. In the state shown in FIG. 2, the switch circuit 2 is supplied to the upright side (upright position side) B1 and B2, and the COM terminal 2
Even if a positive voltage is applied, since the relay contact b is in the "open state", the diode D2 is reverse-biased and the motor does not rotate. Therefore, the mirror does not rotate even if operated incorrectly.

(2) When the mirror is at the storage position In this state, the control circuit 4 is in the state shown in FIG. 3, the relay terminal a is in the "open state", and the relay terminal b is in the "closed state". Then, when the switch circuit 2 is applied to the rising sides B1 and B2 and a positive voltage is applied to the COM terminal 2 and a negative voltage is applied to the COM terminal 1, the motor current is changed to the relay contact b, the motor M, the diode D1, the coil RC and Shunt resistor R
Flows to the COM terminal 1 through the parallel circuit. As a result, the motor M rotates upright, and the mirror rotates in the upright direction. Then, when reaching the upright position, the rotation is mechanically stopped, a lock current flows, and the latching relay RY is quickly operated to reach the state shown in FIG. In the state shown in FIG. 3, even if the switch circuit 2 is applied to the storage sides A1 and A2 and a positive voltage is applied to the COM terminal 1, the diode D1 is in the reverse bias connection because the relay terminal a is "open" and the motor D Does not rotate.

(3) When the mirror is in the forward retracted state This state is when the mirror is originally in the retracted position or the upright position but is shifted to the forward retracted state due to an obstacle or the like. When the position shifts from the standing position, the control circuit 4
Is in the state of FIG. Therefore, when the switch circuit 2 is turned on to the storage sides A1 and A2, the motor M rotates for storage and stops at the storage position. Switch circuit 2 is upright side B1, B2
, The diode D2 is reverse-biased as described above, so that the motor M does not rotate. When the position is shifted from the storage position, the control circuit 4 is in the state of FIG. At this time, the mirror is ahead of the standing position. However, since the control circuit 4 is in the state of FIG. 3, the mirror does not operate on the storage side. Here, once the switch is operated to the upright side B1 and B2, the mirror is stopped at the forward position and the circuit is switched to the state shown in FIG.
1 and A2 to rotate the mirror to the storage position.

(4) When the mirror is between the retracted position and the upright position When the mirror is displaced from the retracted position, the control circuit 4 is in the state shown in FIG.
2 and restore to the standing position. When the position shifts from the standing position, since the control circuit 4 is in the state shown in FIG. 2, the switch circuit 2 is once turned on to the storage sides A1 and A2 to recover to the storage position.

FIG. 4 summarizes the above operations. In such a situation, when the mirror reaches the retracted position and the upright position, the rotation of the mirror mechanically stops, and at the same time, the motor M
, A large drive current flows. This driving current causes the latching relay to operate quickly and cut off the power supply to the motor M. Normally, a shunt resistor is used to prevent the latching relay from operating due to the drive current (normal operating current) flowing when the motor M is operating normally, that is, when the mirror is rotating in the retracted position or the upright position. A malfunction is prevented by diverting a part of the operating current.

Here, when the control circuit operates quickly and there is almost no time lag, and the drive power for turning the mirror is cut off, for example, as described above, a person may be pinched between the mirror and the arm or finger during the turning of the mirror. Even in the case of emergency, the mirror stops rotating and the driving force is immediately cut off, so that there is no fear that the arm or finger will be squeezed and lead to a serious injury. The start of the motor M is performed by turning on the switch circuit 2. At this time, a rush current may flow and the latching relay RY may malfunction. Therefore, as described above, the capacitor and the NTC thermistor NTC are connected to alleviate the rush current.

In the above description, the shunt resistor R is connected in parallel to the coil RC. However, as shown in FIG. FIG. 5A shows that a diode D3 is connected to the coil RC.
And D4 are connected in opposite directions. Therefore, the diodes D3 and D4 complement each other in the bias direction,
The current can flow in any direction. However, in order for a forward current to flow, it is necessary to apply a voltage higher than a built-in potential at a so-called PN junction. This voltage is about 0.6V (in the case of silicon semiconductor)
Therefore, even if an inrush voltage, noise, or the like is input, a malfunction can be prevented if the voltage is equal to or lower than this voltage.

FIG. 5B shows a configuration in which Zener diodes D5 and D6 are connected in series at both ends of the coil RC so that the forward directions are reversed. When the shunt voltage increases and the voltage applied to the Zener diodes D5 and D6 increases, one Zener diode D5 (D6) operates first, and then the other Zener diode D6 (D5) operates. Therefore, either of the Zener diodes D5, D6
Is in a Zener breakdown state, and since this voltage generally occurs at a large voltage, it is possible to prevent a malfunction due to an inrush voltage.

Next, an electric retractable door mirror using the above control circuit will be described. FIG. 6 is a partial sectional view of the electric retractable door mirror according to the present invention. The electric retractable door mirror 1 is configured by fitting a shaft 10 having a shaft portion 11 to a frame 15 to which a mirror (not shown) and a plate outer 30 are attached. Frame 1
5, a sliding portion S having a predetermined height h, an annular frame groove 17 and an arc-shaped groove 31 provided coaxially with the shaft portion 11 of the shaft 10 are provided.
4 is fixed. The shaft 10 has a sliding portion S
The sliding surface Sa, which contacts and slides, the convex shaft rib 16 loosely fitted in the frame groove 17, the shaft stopper 32 loosely fitted in the circular groove 31, and the ball stopper 13 and the ball 13 which contact the side wall of the circular groove 31. A buried hole 12 having a hemispherical cross section is provided.

Further, the shaft 1 is provided with a gear 1 which is movable in the axial direction of the shaft portion 11 and whose rotation around the shaft portion 11 is restricted.
8 (drive means), and the gear 18
The gear 19 (drive means) fixed to the gear 5 meshes.
A ball 22 guided by a ball guide 21 abuts on the gear 18, and the ball 22 is moved downward (toward the ball 13) by a spring 26 via a lower washer 23.
Has been energized. The other end of the spring 26 is regulated by the upper washer 25 and the plate 27.

FIG. 7 is a perspective view of the plate stopper 14 drawn with the surface on which the ball 13 is located as an upper surface.
a and 14b are provided symmetrically,
Surface (convex portion) and L surface (concave portion).

The positioning mechanism of the electric retractable door mirror 1 in the above configuration will be described in detail. FIG. 8 shows the shaft 10,
FIG. 8A is a partial cross-sectional view developed along the annular plate stopper 14 to explain the contact relationship between the ball 13 and the plate stopper 14, and FIG. 8A shows a state in which the mirror is located at the upright position. (B) shows a state where it is located at the storage position. When the motor M is driven, the gear 19 rotates, and the gear 18 meshing with this rotates. However, as described above, since the gear 18 is fixed around the axis of the shaft 10, the gear 19 fixed to the frame 15 rotates around the shaft 10 together with the frame 15. When the mirror moves toward the upright position, the step 14a of the plate stopper 14 comes into contact with the ball 13, and the rotation of the motor M stops mechanically. As described above, the control device 4 cuts off the power supply of the motor M by the drive current that increases due to the stop of the rotation.

When the mirror moves toward the storage position, the shaft stopper 32 comes into contact with the groove end (step portion of the groove) of the arc-shaped groove 31, and the rotation of the motor M is mechanically stopped. The device 4 operates and the power supply is cut off. Further, when the ball 13 comes into contact with an obstacle or the like, the ball 13
4a, and slides on the H surface of the plate stopper 14. Then, the driver turns on the switch circuit 2 of the control device 4 to either the storage side A1, A2 or the upright side B1, B2 so that the position of the mirror becomes a correct position.

As shown in FIG. 8, the ball 13
The L surface of the plate stopper 14 and the gap G1 are provided, and the plate stopper 14 and the shaft 10 are supported by a gap G2. The gaps G1 and G2 are held by the sliding surface S of the frame 15 and the sliding portion S of the shaft 10 abutting and sliding, and the sliding between the top of the ball 13 and the plate stopper 14 is prevented to prevent the plate 13 from sliding. The wear of the stopper 14 is prevented. In addition, since the contact between the sliding portion S and the sliding surface Sa is surface contact, instability such as chattering of the frame 15 can be prevented, and the ball 13 contacts the step 14a and tries to get over it. However, it is possible to prevent the inclination of the frame 15.

The shaft rib 16 provided on the shaft 10 protrudes in a convex shape, and the frame groove 17 is loosely fitted in the shaft rib 16, so that foreign matters such as water, dust, dust and the like can be prevented from entering. . Thereby, the frame 1 due to foreign matter
The instability with respect to the rotation of 5 is prevented.

[0040]

As described above, by using the control device using the latching relay, the number of parts can be reduced and the position of the door mirror can be controlled simply and inexpensively. Further, the control device can be provided in a unit or the like in the cab, so that the weight of the electric retractable door mirror has been reduced. Further, since the stop position of the door mirror is performed at the same time when the rotation of the motor is stopped, the stop position accuracy of the mirror is improved. As described above, the quality of the electric retractable mirror is improved and the reliability is improved. In addition, even in the case of emergency, there is almost no time lag and the power circuit is shut off, improving user safety.

[Brief description of the drawings]

FIG. 1 is a view for explaining the operating principle of a latching relay used in the present invention. FIG. 1 (a) shows a door mirror in an upright position.
(B) shows the state where the door mirror is in the storage position.
Have .

FIG. 2 is a circuit diagram of the control device according to the present invention, showing a standby state at a storage position.

FIG. 3 is a circuit diagram of the control device according to the present invention, showing a standby state to a standing position.

FIG. 4 is a table showing mirror operating states in respective states of a control circuit and mirror positions.

FIG. 5 Latching used in the circuit of FIG. 3 or FIG.
(A) is a coil showing a modification of the relay part.
(B) shows the state where two diodes are connected to the coil
Shows a state where two Zener diodes are connected
It is .

FIG. 6 is an electric retractable door illustrating an embodiment of the present invention .
FIG .

FIG. 7 is a perspective view of the plate stopper 14 shown in FIG . 6;
FIG .

FIG. 8 shows a plate stopper 14, a ball 13, and a shaft.
FIG. 7A is a partial cross-sectional view illustrating a contact state of a shaft, and FIG.
(B) shows the storage position .

FIG. 9 shows a conventionally used electric retractable door mirror.
FIG .

10 is a plan view of the pivot shaft 50 in FIG .
FIG .

11 is a part developed along arrow III in FIG .
It is sectional drawing .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric retractable door mirror 2 Switch circuit 3 Control circuit 4 Control device 10 Shaft 11 Shaft part 13 Ball 14 Plate stopper 15 Frame 16 Shaft rib 17 Frame groove 18, 19 Gear (drive means) 29 Frame position detecting means 31 Arc-shaped groove 32 Shaft stopper h Height of sliding part c Condenser M Motor (drive means) R Shunt resistor RY Latching relay D1-D4 Diode D5, D6 Zener diode NTC NTC thermistor S Sliding part Sa Sliding surface

Continuation of the front page (56) References JP-A-4-339039 (JP, A) JP-A-4-110245 (JP, A) JP-A-4-178184 (JP, A) JP-A-2-290754 (JP) , A) Japanese Utility Model Application Hei 3-99660 (JP, U) Japanese Utility Model Application Hei 5-44688 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60R 1/074

Claims (6)

(57) [Claims] 1. A control device for an electric retractable door mirror, wherein a mirror body provided with a mirror is rotated to a standing position and a storage position by driving means, wherein the mirror body is rotated in a standing position direction or a storage position direction. A switch circuit for switching the polarity of a current flowing through the driving means, a latching relay having a coil connected in series to the driving means, and a shunt resistor connected in parallel to the coil, and the mirror body rotates. When the drive means is locked by reaching the standing position or the storage position, the shunt voltage generated by the shunt resistor increases, and when the shunt voltage becomes larger than the sense voltage of the latching relay, the latching relay is turned on. Operates to cut off the power supply to the driving means, and the switch circuit switches the cutoff state. Comprising a control circuit for holding until electric retractable control device of the door mirror, characterized in that. 2. The resistance value of the shunt resistor is 0.5 to 0.5 .
The control device for an electric retractable door mirror according to claim 1, wherein the control device is set to 2Ω. 3. The sensing voltage of the latching relay is:
The electric retractable door mirror control device according to claim 1, wherein the controller is set to 0.5 to 2V. 4. An NTC thermistor is connected in series with the latching relay, and a capacitor is connected in parallel with the NTC thermistor to reduce an inrush current for starting a motor generated when the switch circuit is turned on. The control device for an electric retractable door mirror according to claim 1. 5. The control circuit includes two diodes connected in parallel with their forward directions reversed so that one of them becomes a forward bias connection irrespective of the direction of the current, and the diode is connected in series to the coil. The control device for a power-retractable door mirror according to claim 1, wherein the control device is provided in parallel with the shunt resistor. 6. The control circuit has a pair of zener diodes connected in reverse with respect to each other with the latching relay interposed therebetween, and the shunt resistor is connected in parallel with the circuit. The control device for an electric retractable door mirror according to claim 1.