JP2963349B2 - Outer mirror heater 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 a heater control device for an outer mirror for removing frost and raindrops attached to a mirror surface.

[0002]

2. Description of the Related Art A heater mirror has been put to practical use in which a heating element is disposed on the back surface of a mirror to remove frost and raindrops attached to the mirror surface. Conventional methods for controlling the energization of a mirror heating heater include: a. The driver of the vehicle directly controls energization of a heating element provided on the back of the mirror by opening and closing an operation switch in the vehicle compartment (Japanese Utility Model Application Laid-Open No. 58-47531). b. An operation switch and a vehicle speed detection switch or a pressure switch for detecting wind pressure during traveling and the heating element are connected in series, and control is performed so that the heating element can be energized by opening and closing the operation switch only during traveling of the vehicle (actually, Kosho 62-2
No. 4591). c. The heating element and the heating element for the rear defogger are connected in parallel, and the energization to the heating element is collectively and directly controlled together with the heating element for the rear defogger by opening and closing an operation switch (Japanese Unexamined Utility Model Publication No. 1-52835). d. A control circuit including a timer circuit 52 for setting a timer time by a capacitor, a resistor, or the like shown in FIG. 5 is provided, and the heating element 55 is energized for a set time by an input of an operation switch 54. e. As seen in imported cars and the like, the heating element is energized only when the outside air temperature is equal to or lower than a set temperature by a temperature sensor.

[0003]

However, the above-mentioned prior art has the following problems. That is, in a, when the driver forgets to turn off the operation switch, the power supply to the heating element is continued, and unnecessary power consumption is caused. In b, since the heating element cannot be energized when the vehicle is stopped, traveling in a state where frost or raindrops are attached at the start of traveling is inevitable. There is. In (c) and (e), it is difficult to optimize the set temperature at the time of rainfall in a season when the temperature is high, and in the former case, the power consumption is large because the temperature is always interlocked with the rear defogger heating element. In addition, power consumption due to the driver forgetting to turn off becomes a problem. In the case of d, as shown in FIG. 5, a stabilized power supply circuit 50, a switch input circuit 51, a timer circuit 5, a capacitor, a resistor, an IC, a transistor, a relay and the like are used.
2. Since the initialization circuit 53 is required, there is a problem that the cost is increased. Further, if the set time is lengthened, both the capacitor and the resistor for setting the timer time become elements having large external dimensions, and there is a problem that the space required for the control circuit becomes large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a heater control device for an outer mirror, which is compact and inexpensive and ensures reliable control of energization of a heating element of the outer mirror. is there.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a water droplet is heated by heating a mirror surface.
In front of the vehicle outer mirror with a heating element to remove
In a heater control device for controlling the energization of the heating element,
A DC power supply, interposed between the heating element and the DC power supply.
And the contact that is turned on when the operation switch is turned on.
A self-holding circuit for self-holding.
A PTC thermistor is interposed on the road, and the operation switch
After a lapse of a predetermined time from the introduction of the PTC thermistor,
The current value flowing through the self-holding circuit due to heat generation is suppressed,
The feature is that the self-holding circuit is shut off. Claims
The invention described in Item 2 relates to a method of heating a mirror surface to remove water droplets.
The outer mirror for a vehicle equipped with a body passes through the heating element.
In a heater control device that controls power, a DC power
Relay contact interposed between the heating element and the DC power supply
, An operation switch, and a relay interlocked with the relay contact
It consists of a series connection circuit of a coil and a PTC thermistor.
The relay contact turns on when the operation switch is turned on.
In response to this signal, the conduction state of the relay coil is changed to
A self-holding circuit for holding, the operation switch
After a lapse of a predetermined time from the introduction of the PTC thermistor,
The current value flowing to the self-holding circuit due to heat generation is suppressed,
The self-holding circuit is shut off. Claim 3
The invention described above is characterized in that the PTC thermistor, the relay coil and
The relay contact is located inside the housing of the operation switch in the cabin.
It is characterized by being stored. The invention according to claim 4.
Supplies current in parallel to the PTC thermistor
To adjust the temperature rise of the PTC thermistor over time
It is characterized by the installation of a resistor.

[0006]

The power supply to the heating element, which is a heater for heating the outer mirror provided on the back of the outer mirror, can be started by the driver of the vehicle through a relay circuit by operating an operation switch as necessary. Switches the relay due to a trip caused by a sudden increase in the resistance value due to heat generation of the PCT thermistor inserted in series with the relay coil, and stops the power supply after a predetermined time has elapsed.

[0007]

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing a schematic configuration of a heater device for heating an outer mirror according to the present invention. As shown in FIG.
The heater control device for the outer mirror includes a control circuit 10 and an outer mirror 20 having a heating element 15 for a heater for heating. The control circuit 10 includes an operation switch 11, a relay coil 12, a PTC thermistor 13, and an adjustment resistor 2
A series relay circuit 21 including 8, 29, 30; a relay contact circuit 22 including a relay contact 16 (a contact) connecting the power supply and the heating element 15; and a self-holding circuit including a diode 17 for self-holding the relay. 23.

FIG. 2 is an exploded perspective view of a housing 27 of the operation switch. The housing 27 incorporates a board 26 on which the relay coil 12 of the control circuit, the relay contact 16, the PTC thermistor 13, the diode 17 forming the self-holding circuit 23, the connector 25 and the like are mounted. A heater switch may be provided in the housing of the electric storage / electric remote control switch and mounted on the board. FIG. 3 is an exploded perspective view when the heating element 18 is formed of a PTC sheet heating element. The PTC sheet heating element 18 is adhered to the back surface of a mirror 19 with a double-sided adhesive tape. FIG. 4 is a (ambient) temperature-resistance characteristic diagram of the PTC thermistor.

Since the control circuit of the present invention has the above configuration, it operates as follows. When input to the operation switch 11, the relay coil 12
Series relay circuit 21 including PTC and PTC thermistor 13
Is energized. The contact 16 of the relay a is inverted, and the heating element 15 for heating the outer mirror is energized. At the same time, the self-holding circuit 23 composed of the diode 17 is operated, and the operation switch 11 is turned off.
Even if it becomes, it is self-held. When the Curie temperature is reached due to the heat generated by the PTC thermistor after a lapse of a certain time, the resistance value rapidly increases as shown in FIG. 4 and the current stops flowing (trip). When the current value falls below a value sufficient to excite the relay coil 12, the relay a contact 16 is restored and the power supply to the heating element 15 is released. Further, the self-holding of the relay 24 is also released at the same time, and returns to the initial state. If the IGN (ignition) power supply is turned off due to the stop of the engine before the PTC thermistor 13 trips, no current flows through the relay coil 12 in the same manner.
The self-holding of No. 4 is released and the state returns to the initial state. The current flowing through the relay coil 12 is 50 V at 12 V.
Since the current is about 100 mA, it is preferable to use a PTC thermistor having a characteristic of raising the temperature to the Curie temperature in about 10 minutes at room temperature with this current, but this current value is increased or decreased by the adjusting resistors 28, 29 or 30. it can.
When the resistor 28 is added, the current flowing through the relay coil 12 and the current flowing through the PTC thermistor 13 decrease, and the resistance 29
Is added, the current flowing through the relay coil 12 increases,
The current flowing through the PTC thermistor 13 decreases. Resistance 3
When 0 is added, the current flowing through the relay coil 12 decreases, and the current flowing through the PTC thermistor 13 increases. P
The energization time is set by the current-temperature rise characteristic of the TC thermistor and the adjusting resistor.

[0010]

As described above, according to the present invention, the energization of the heating element which is the heater for heating the outer mirror provided on the back surface of the outer mirror is started by the operation of the operation switch by the driver of the vehicle as required. Can be energized at any time, and after energization, the relay is switched by a trip due to a sudden increase in resistance due to the heat generated by the PCT thermistor inserted in series with the relay coil, and the energization is stopped after a predetermined time elapses. It can be done reliably.

[0011] Other effects of the present invention are listed below. 1. The power supply to the outer mirror heating heater is interrupted for a certain time after the operation switch is turned on, so that the driver does not forget to turn off the switch, and wasteful power consumption of the mounted battery can be reduced. 2. Removes raindrops, frost, etc. without interlocking with the rear defogger. 3. A stabilizing power supply circuit or the like found in a conventional control circuit using a timer is unnecessary, and a low-cost control device can be provided. 4. Since the number of components is small and compact and can be mounted on a switch board, a controller (control circuit unit) is not required, and space can be saved. 5. In the case of defrosting and thawing in winter, it is desirable to supply electricity for a longer time than removing raindrops. However, the lower the ambient temperature, the longer the time required for the PTC thermistor to generate heat, so that it is practically convenient. 6. Since the PTC planar heating element is used as a heater for the outer mirror, there is no need to control the mirror surface temperature, and it is safe even if the trip time of the thermistor changes depending on the ambient temperature.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an outline of a heater control device for an outer mirror according to the present invention.

FIG. 2 is an exploded perspective view showing a state in which a switch board equipped with a relay, a PTC thermistor, a diode forming a self-holding circuit, a connector, and the like in FIG. 1 is incorporated in a switch box.

FIG. 3 is an exploded perspective view when a heating element of the outer mirror heating heater of the present invention is configured by a PTC planar heating element.

FIG. 4 is a temperature-resistance characteristic diagram of a PTC thermistor.

FIG. 5 is a diagram showing a control circuit including a conventional timer circuit.

[Description of Signs] 10 Control circuit 11 Operation switch 12 Relay coil 13 PTC thermistor 15 Heating element 16 Relay contact (a contact) 17 Diode 18 PTC planar heating element 19 Mirror 20 Outer mirror 21 Series relay circuit 22 Relay contact circuit 23 Self Holding circuit 24 Relay 25 Connector 26 Switch base 27 Switch box 28, 29, 30 Adjusting resistor

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60S 1/60

Claims (4)

(57) [Claims] 1. An electric power supply to a heating element of a vehicle outer mirror having a heating element for heating a mirror surface to remove water droplets.
In the heater control device for controlling , a DC power supply, a contact interposed between the heating element and the DC power supply, and a self-holding device that automatically holds the contact when an operation switch is turned on.
A self-holding circuit , wherein the self-holding circuit is provided with a PTC thermistor,
After a predetermined time has elapsed since the operation switch was turned on, the PT
Current value flowing through the self-holding circuit due to heat generated by the C thermistor
A heater control device for an outer mirror , wherein the self-holding circuit is cut off . 2. An electric power supply to the heating element of an outer mirror for a vehicle having a heating element for heating a mirror surface to remove water droplets.
In a heater control device for controlling , a DC power supply and a relay connection interposed between the heating element and the DC power supply.
Point, operation switch, and relay coil
And a PTC thermistor and a series connection circuit,
When the operation switch is turned on, the relay contact turns on.
In response to this signal, the conduction state of the relay coil is maintained.
And a self-holding circuit for holding the P switch after a lapse of a predetermined time from the turning on of the operation switch.
Current flowing in the self-holding circuit due to heat generated by the TC thermistor
A heater control device for an outer mirror , wherein the value is suppressed and the self-holding circuit is shut off . 3. The outer according to claim 2, wherein the PTC thermistor, the relay coil, and the relay contact are built in a housing of an operation switch in a vehicle compartment.
-Mirror heater control. 4. A parallel connection to said PTC thermistor.
In addition, the temperature rise of the PTC thermistor with respect to the current supply time
Claims characterized by installing a resistor for adjusting the
Item 3. An outer mirror heater control device according to item 2 .