JPH05208645A - Auxiliary power supply unit for vehicle - Google Patents

Abstract

PURPOSE:To realize sureness of protecting action of an on-car battery from overcurrent and protecting action against abnormal temperature rise and to realize simplification of maintenance. CONSTITUTION:Three sockets are constituted. In the three sockets, power is fed from an on-car battery 26 by each of paired socket bodies 8a, 9a, 10a and terminals 8c, 9c, 10b. In a regular condition, an exciting coil 18b is electrified through a transistor 19, and power is fed to each socket through normally open side contacts (c-a) of a relay switch 18a. In a current supervisory circuit 22, when a load current of flowing through a shunt resistor 17 exceeds a preset value, the transistor 19 is turned off to interrupt power of the exciting coil 18b through a holding circuit 23 and a transistor 21, and an electrification line relating to the socket is interrupted. When a temperature of the socket abnormally rises, a switch element SW1 or SW2 of containing a bimetal is turned on, and since a short-circuiting circuit is formed, it is detected by the current supervisory circuit 22 to interrupt the electrification line relating to the socket.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary power supply device for a vehicle, which is adapted to obtain a power source for a plurality of electrical appliances for a vehicle from a plurality of sockets provided in the vehicle.

[0002]

2. Description of the Related Art In recent years, electric appliances such as a television receiver and a CD player have been increasingly used in the interior of an automobile. The power source for such electric appliances is provided on the dashboard of the automobile. It is generally obtained from a cigarette lighter socket. In this case, since only one cigarette lighter socket is provided in an automobile, an auxiliary power supply device for obtaining a power source for a plurality of electric appliances is put to practical use.

That is, this type of auxiliary power supply device has a structure in which a plug connected to a cigarette lighter socket and a plurality of sockets branched from the plug are provided, or an electric appliance in addition to the cigarette lighter socket. 1 to 2 sockets that can be connected to are provided, and these are connected to a vehicle-mounted battery. In this case, in the conventional auxiliary power supply device, in order to protect the in-vehicle battery from overcurrent,
A plurality of current fuses are provided corresponding to each socket, and a temperature fuse is also provided as a measure against abnormal temperature rise.

[0004]

In the above conventional configuration, when an overcurrent flows and the current fuse is blown, and when the temperature fuse is blown due to an abnormal temperature rise, those fuses must be replaced one by one. There is a problem that the maintenance becomes troublesome. Further, in the auxiliary power supply device, the total breaking capacity of each current fuse is relatively large due to the connection of a plurality of electric appliances. Therefore, before the current fuse on the auxiliary power supply device side is blown, , There is a possibility that the main fuse connected between the auxiliary power supply unit and the on-board battery will be blown,
In such a case, maintenance becomes more troublesome.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to surely perform a protection operation of an on-vehicle battery from an overcurrent and a protection operation against an abnormal temperature rise, and also to simplify maintenance. It is an object of the present invention to provide an auxiliary power supply device for a vehicle, which has effects such as being able to.

[0006]

In order to achieve the above object, an auxiliary power supply device for a vehicle according to the present invention has a plurality of sockets fed from an on-vehicle battery to obtain a power source for a vehicle electrical appliance. In the auxiliary power supply for use, a current monitoring circuit is provided for shutting off the power supply path to the socket when the load current flowing through the socket exceeds a set value, and the temperature detected by the socket is detected. Is provided with a thermal responsive member that short-circuits the power supply path to the socket when the temperature exceeds the upper limit temperature value.

In this case, it is also possible to provide a voltage monitoring circuit that shuts off the power supply path to the socket when the output voltage of the on-vehicle battery becomes equal to or lower than the set lower limit voltage.

Further, it is possible to provide a reset switch for canceling the cutoff state of the energization path by the current monitoring circuit and the voltage monitoring circuit.

[0009]

When the load current flowing through the socket exceeds the set value, the current monitoring circuit shuts off the power supply path to the socket, so that the on-vehicle battery is protected from overcurrent. When the temperature of the socket rises abnormally and becomes equal to or higher than the upper limit temperature value, the heat responsive member short-circuits the power supply path to the socket. Then, the load current flowing through the socket will exceed the set value,
The current monitoring circuit cuts off the power supply path to the socket, thereby performing protection operation against abnormal temperature rise.

When the voltage monitoring circuit is provided, the power supply path to the socket is cut off when the output voltage of the vehicle battery becomes equal to or lower than the set lower limit voltage.
It is possible to prevent the vehicle-mounted battery from being over-discharged and protect it.

When the reset switch is provided, it is possible to release the conduction path cutoff state by the current monitoring circuit and the voltage monitoring circuit simply by operating the reset switch, which is convenient in actual use.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 4, at the tip of the power cord 2 led out from the main body case 1, there is provided a connecting plug 3 which is connected by insertion to a cigarette lighter socket (not shown) provided in the automobile, and the connection state thereof. Then, the power cord 2 is connected to both ends of the vehicle-mounted battery via the main fuses (not shown) to provide a power supply state.

The body case 1 has a base portion 4 having three openings 4a to 4c arranged in a line at the rising portion on the front surface.
And a cover 5 provided so as to cover it, and in particular, the openings 4a and 4b are provided with lids 4d and 4e for opening and closing the cover. A light emitting diode 6 for displaying a power-on state is provided at the rising portion of the base portion 4.

In FIG. 1, sockets 8 and 9 into which a power supply plug 7 of a vehicle electrical appliance is inserted are provided at positions corresponding to the openings 4a and 4b in the main body case 1, and the openings 4c and At a corresponding position, a well-known socket 10 for a cigarette lighter (not shown) is provided. The power plug 7 has a plus pole 7a at its tip,
This is a well-known structure having a pair of ground electrodes 7b on the side.

As shown in FIG. 2, the sockets 8 and 9 are
A bottomed cylindrical socket body 8a, 9a made of a conductive metal, into which the power plug 7 is inserted, and terminals 8c, 9c fixed to the bottom of the socket body 8a, 9a via insulating insulators 8b, 9b. Be prepared.

In this case, the socket bodies 8a, 9a
Are bridged by a connecting plate 11 made of a conductive metal, which is bridged between the outer bottom parts thereof, and the connecting plate 11 is connected to the ground side line 2a of the power cord 2. Further, the insulating insulators 8b and 9b are formed into the through holes 11a and 11b formed in the connecting plate 11, and the terminals 8c and 9c have the through holes 11a and 11b.
It is projected to the outside of the socket bodies 8a and 9a via a and 11b.

A conductive plate 12 is attached to the protruding portions of the terminals 8c and 9c so as to bridge them. The conductive plate 12 is attached by tightening nuts 12a and 12b on the threaded portions formed on the protruding portions of the terminals 8c and 9c. At this time, the conductive plate 12 and the connecting plate 1 are attached.
1, and washer-shaped insulating spacers 13a and 13b are interposed therebetween.

Further, when the conductive plate 12 is attached as described above, as shown in FIG.
Bimetal plates 14a and 14b, which are heat responsive members, are fastened together between a and 13b and the conductive plate 12. The bimetal plates 14a and 14b detect the temperatures of the socket bodies 8a and 9a (and thus the temperatures of the sockets 8 and 9), and the bimetal plates 14a and 14b shown in FIG.
It is deformed as shown in (b), and its tip is configured to come into contact with the connecting plate 11 when the temperature becomes equal to or higher than a preset upper limit temperature.

Therefore, the two-circuit thermal switch elements (indicated by SW1 and SW2 in FIG. 5 to be described later) are connected in parallel by the connecting plate 11, the conductive plate 12 and the bimetal plates 14a and 14b. Is obtained.

From the connecting plate 11, the arm portion 11
c is integrally extended, and this arm portion 11c is connected to the socket body 10a which also functions as the ground side terminal of the cigarette lighter socket 10. The positive terminal 10b of the socket 10 includes a lead wire 10c and a circuit unit 1 housed in the body case 1.
The printed wiring board 15a and the lead wire 15b of No. 5 are relayed and connected to the conductive plate 12.

The circuit unit 15 is directly connected to the power supply side line 2b of the power supply cord 2 and also connected to the ground side line 2a of the power supply cord 2 via the lead wire 15c and the connecting plate 11. .. The circuit unit 15 is connected to the conductive plate 12 via the lead wire 15b as described above.

Now, FIG. 5 schematically shows an electrical configuration of the circuit unit 15, which will be described below. That is, in FIG. 5, as described above, the connecting plate 11,
The two-circuit thermal switch elements composed of the conductive plate 12 and the bimetal plates 14a and 14b are denoted by SW1 and SW.
2, the switch elements SW1 and SW2 are connected at one end to the terminals 8c, 9c, 10b of the sockets 8, 9, 10 and at the other end to the socket bodies 8a, 9a, 10a. It will be in a state of

Terminals T1 and T2 are connected to the earth side line 2a and the power source side line 2b of the power cord 2, respectively. Especially, the terminal T1 is the socket body 8a, 9 described above.
It is in a state of being connected to a and 10a.

Terminal T2 and terminals 8c, 9c, 10b
Between the shunt resistor 17 for detecting the load current and the relay 18 (also shown in FIG. 1) functioning as an overcurrent protection switch, the normally open contact (c) of the relay switch 18a.
-A) is interposed in series, and the light emitting diode 6 is provided between the contact a of the relay switch 18 and the terminal T1.
Are connected via a current limiting resistor 16. Relay 1
The exciting coil 18b of No. 8 has one end connected to the terminal T2,
The other end is connected to the terminal T1 via the collector-emitter of the npn-type transistor 19. The base of the transistor 19 is connected to the terminal T2 via the resistor 20, and is also connected to the terminal T1 via the collector-emitter of the npn-type transistor 21.

The current monitor circuit 22 detects the load current flowing through the shunt resistor 17 (that is, the load current flowing through the sockets 8, 9, 10) based on the voltage across the shunt resistor 17, and the detected current value is set. The holding circuit 23 is operated when the value exceeds the value.

This holding circuit 23 is supplied with power from between the terminals T1 and T2, and turns on the transistor 21 when a certain delay time elapses after the start of operation, and turns on the transistor 21 in this way. The state is held during the period when the voltage signal is applied to the terminal Q, and the relay switch 18 is connected to the terminal Q.
The normally closed contact b of a is connected. The power supply side line 2b connected to the terminal T2 is connected to the main fuse 24 and A
It is connected to the positive terminal of the on-vehicle battery 26 via the CC switch 25.

Next, the operation of this embodiment configured as described above will be described. That is, when the ACC switch 25 is turned on while the connecting plug 3 is inserted in the cigarette lighter socket (not shown), the circuit unit 15 is powered.
Within 5, the transistor 19 is turned on and the relay coil 18b is energized. As a result, the normally open contacts (ca) of the relay switch 18 are turned on, so that the terminals 8c, 9c, 1 of the sockets 8, 9, 10 are connected.
0b is connected to the vehicle-mounted battery 26 via the contacts (ca) and the shunt resistor 17 and the like.

Therefore, the sockets 8, 9 and 10 come to be in the power supply state, and when the power source plug 7 of the electric appliance for vehicle is inserted into the sockets 8 and 9, the electric power can be supplied to these electric appliances. , The socket 10 can be used for a cigarette lighter. In addition, it is displayed that the light emitting diode 6 is energized and lit to supply power.

In such a state, the current monitoring circuit 22
Detects the load current flowing through the sockets 8, 9, 10 through the shunt resistor 17, and operates the holding circuit 23 when the detected current value exceeds the set value. Then, the holding circuit 23 turns on the transistor 21 when a certain delay time elapses, and accordingly, the transistor 19 is turned off and the relay coil 18 is turned off.
b is cut off, and the relay switch 18a is a contact (c-a).
And the normally closed contact (c-b) is switched on. As a result, the energization paths to the sockets 8, 9, 10 are cut off, and a voltage signal is applied to the terminal Q of the holding circuit 23 from between the contacts (c-b). The transistor 21 is kept in the ON state, and thus the cut-off state of the energization path for the sockets 8, 9 and 10.

Now, when the temperature of the sockets 8, 9 rises due to the use of electrical equipment in the state where the current paths are formed for the sockets 8, 9, 10, the bimetal plates 14a, 14b are deformed accordingly. Comes to
When the temperature becomes equal to or higher than a preset upper limit temperature, the tip of either one of the bimetal plates 14a and 14b comes into contact with the connecting plate 11 first, and the thermal switch element code S
Either W1 or SW2 comes into the ON state.

Then, the shunt resistor 17 and the sockets 8, 9 through the contacts (ca) of the relay switch 18a,
Since the energizing path for 10 is short-circuited and a large current flows through the shunt resistor 17, the current monitoring circuit 22 which detects this causes the holding circuit 23 to operate and disconnect the relay coil 18b. In response to this, the contacts (ca) of the relay switch 18a are turned off, and the power supply paths to the sockets 8, 9 and 10 are cut off.

The operation state of the holding circuit 23 can be released by turning off the power of the circuit unit 15 by turning off the ACC switch 25 or pulling out the connecting plug 3 from the cigarette lighter socket.

In short, according to the present embodiment described above, it is possible to obtain the power supplies for the two electric appliances for vehicles and the cigarette lighter through the sockets 8 to 10. In this case, an excessive load current flows, When the temperature rises abnormally, the load energization path can be surely cut off, and the on-vehicle battery 26 can be protected. Moreover, in this case, it is not necessary to replace the current fuse or the temperature fuse as in the conventional configuration, and the maintenance can be simplified. Further, in providing the two thermal switch elements SW1 and SW2,
Since the connecting plate 11 is also used as a contact element, the overall structure can be simplified.

FIGS. 6 to 11 show a second embodiment of the present invention, and only the parts different from the first embodiment will be described below. In FIG. 10, a cigarette lighter 28 is attached to an instrument panel 27 of an automobile.
The main body case 29 having a rectangular shape is provided so as to be exposed at a position adjacent to the front side of the main body case 29. As shown in FIG.
c are provided in a row, and these openings 30
Lids 31a to 31c for opening and closing a to 30c are provided. Further, on the front surface of the main body case 29, a light emitting diode 6 for displaying a power-on state and a reset switch 32 described later are provided.

In FIG. 6 corresponding to FIG. 1 in the first embodiment, the tip of the power cord 2 led out from the main body case 29 has a main fuse 24 and an ACC switch 2.
5 is connected to the positive terminal of the vehicle-mounted battery 26 via 5 (see FIG. 11). Further, in the main body case 1, a socket 33 into which a power plug (not shown) of a vehicle electrical appliance is inserted at positions corresponding to the openings 30a to 30c.
~ 35 are provided.

As shown in FIG. 7, sockets 33-35 are also provided.
Is a bottomed cylindrical socket body 33a to 35a made of a conductive metal into which the power plug is inserted, and insulating insulators 33b to 35 at the bottoms of these socket bodies 33a to 35a.
It is provided with terminals 33c to 35c fixed via b.

In this case, the socket bodies 33a to 3a
5a is bridged by a connecting plate 36 made of a conductive metal, which is bridged between the outer bottom parts, and the connecting plate 36 is connected to the ground side line 2a of the power cord 2. Further, the insulating insulators 33b to 35b are formed in a shape to be inserted into the through holes 36a to 36c formed in the connecting plate 36, and the terminals 33c to 35c are
Socket body 33a through each through hole 36a to 36c
~ 35a is projected outside.

A conductive plate 37 is attached to the protruding portions of the terminals 33c to 35c so as to bridge them. In addition, the mounting of the conductive plate 37,
This is done by tightening nuts 37a to 37c on the threaded portions formed on the protruding portions of the terminals 33c to 35c. At this time, a washer-shaped insulating spacer 38a is provided between the conductive plate 37 and the connecting plate 36. ~ 3
8c is interposed.

When the conductive plate 37 is attached, as shown in FIG. 8A, the insulating spacer 38a is formed.
38c and the conductive plate 37, bimetal plates 39a to 39c, which are heat responsive members, are fastened together. The bimetal plates 39a to 39c detect the temperatures of the socket bodies 33c to 35c (therefore, the temperatures of the sockets 33 to 35) and deform as shown in FIG. 8B, and the temperatures are preset. When the temperature becomes equal to or higher than the upper limit temperature, the tip of the upper end contacts the connecting plate 36.

Therefore, by the connecting plate 36, the conductive plate 37, and the bimetal plates 39a to 39c, there are three circuits of thermal switch elements connected in parallel (symbols SW3, SW4, and SW5 are given in FIG. 11 described later). Is shown) is obtained.

Returning to FIG. 6, the circuit unit 40 is directly connected to the power source side line 2b of the power cord 2, and is connected to the ground side line 2a of the power cord 2 via the lead wire 40a and the connecting plate 36. Connected. still,
The circuit unit 40 includes a lead wire 4 for the conductive plate 37.
It is in a state of being connected via 0b.

In the following, FIG. 11 schematically showing the electrical structure of the circuit unit 40 will be described. That is,
In FIG. 11, as described above, the connecting plate 36 and the conductive plate 3 are
3 composed of 7 and bimetal plates 39a to 39c
The thermal switch elements of the circuit are denoted by SW3, SW4 and SW
5, the switch elements SW3 to S3 are shown.
W5 has a terminal 33 with sockets 33 to 35 at each end.
c-35c and the other end is socket body 33a-
It will be in the state connected to 35a. Further, of the terminals T1 and T2 respectively connected to the ground side line 2a and the power source side line 2b of the power cord 2, especially the terminal T1 is in a state of being connected to the socket bodies 33a to 35a.

In the circuit unit 40, as in the first embodiment, the shunt resistor 17, the relay 18 including the relay switch 18a and the exciting coil 18b (also shown in FIG. 6), the light emitting diode 6, and the current limiting resistor. 16, a transistor 19 and 21, a resistor 20, a current monitoring circuit 22, and a holding circuit 23 are provided, and in addition to this, a voltage monitoring circuit 41.
Also, the reset switch 32 is provided.

The voltage monitoring circuit 41 is used for the on-vehicle battery 2
The output voltage of 6 is monitored via terminals T1 and T2, and when the monitored voltage becomes equal to or lower than a set lower limit voltage (for example, 9 V when the rated output voltage of the on-vehicle battery 26 is 12 V), the holding circuit 23 is turned on. It is configured to operate.
The reset switch 32 is of a normally closed type and is interposed between the terminal T1 and the shunt resistor 17. When the reset switch 32 is off, the power of the holding circuit 23 is cut off to cancel the holding operation of the holding circuit 23. Is configured to.

Therefore, according to the present embodiment constructed as described above, the following effects can be obtained in addition to the same effects as those of the first embodiment.

That is, when the output voltage of the on-vehicle battery 26 becomes equal to or lower than the set lower limit voltage, the voltage monitoring circuit 41 activates the holding circuit 23. Then, the holding circuit 23 turns on the transistor 21 after a certain delay time elapses, and accordingly, the transistor 19 is turned off and the relay coil 18b is cut off.
8a turns off the contact (c-a), and the normally-closed side contact (c-
b) The state is switched on. As a result, the energization path to the sockets 33 to 35 is cut off, and a voltage signal is applied to the terminal Q of the holding circuit 23 from between the contacts (c-b). ON state, and by extension sockets 33 to 3
Thus, the cut-off state of the energization path for 5 will be maintained. As a result, it is possible to prevent the on-vehicle battery from falling into an over-discharged state and shortening its life.
The protection from over discharge of No. 5 can be surely performed.

Further, when the reset switch 32 is operated, the holding operation by the holding circuit 23 as described above is canceled, so that it is possible to easily release the energization path cutoff state by the holding circuit 23. It is convenient for actual use.

[0048]

As is apparent from the above description, according to the vehicle auxiliary power supply device of the first aspect, the load current flowing through the socket for obtaining the power source of the vehicle electrical equipment has the set value. An overcurrent protection switch is provided that shuts off the energization path to the socket when it is exceeded, and when the temperature of the socket exceeds the upper limit temperature, the energization path to the socket is short-circuited to operate the overcurrent protection switch. Since the heat responsive member is provided, it is possible to surely perform the protection operation against the overcurrent and the abnormal temperature rise, and it is possible to achieve the practical effect that the maintenance can be simplified.

According to the second aspect of the present invention, in addition to the above configuration, the voltage monitoring circuit that shuts off the power supply path to the socket when the output voltage of the on-vehicle battery becomes equal to or lower than the set lower limit voltage. Since it is configured to provide
The effect that the vehicle-mounted battery can be surely protected from over-discharge can also be achieved.

According to the third aspect of the present invention, since the auxiliary power supply device for a vehicle is provided with the reset switch for canceling the current cutoff state by the overcurrent protection switch and the voltage monitoring circuit, the current cutoff state is provided. Can be easily released, which is very convenient in actual use.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention with a cover portion removed.

FIG. 2 is an enlarged cross-sectional plan view of a main part.

FIG. 3 is an enlarged perspective view of a main part.

FIG. 4 is an overall perspective view

FIG. 5 is a connection diagram showing an electrical configuration.

FIG. 6 is a plan view showing a second embodiment of the present invention.

FIG. 7 is a view corresponding to FIG.

FIG. 8 is a view corresponding to FIG.

[Figure 9] Front view

FIG. 10 is a perspective view showing an arrangement state.

FIG. 11 is a view corresponding to FIG.

[Explanation of symbols]

In the figure, 1 and 29 are body cases, 2 is a power cord, 3 is a connecting plug, 4 is a base part, 5 is a cover part, 7 is a power plug, and 8, 9, 10, 33, 34 and 35 are sockets. ,
11, 36 are connecting plates, 12, 37 are conductive plates, 14a, 1
4b, 39a, 39b, and 39c are bimetals (thermal response members), 15 and 40 are circuit units, 17 is a shunt resistor, 18 is a relay, 22 is a current monitoring circuit, 23 is a holding circuit, 26 is a vehicle battery, and 32 is a reset. Switch, 4
1 is a voltage monitoring circuit, SW1, SW2, SW3, SW4,
SW5 indicates a switch element.

Claims (3)

[Claims] 1. An auxiliary power supply device for a vehicle, wherein a power source for a vehicle electrical appliance is obtained from a plurality of sockets fed from an on-vehicle battery, when a load current flowing through the socket exceeds a set value. A current monitoring circuit for shutting off the power supply path to the socket, and a thermal response member provided to detect the temperature of the socket and short-circuiting the power supply path to the socket when the detected temperature exceeds the upper limit temperature value. An auxiliary power supply device for a vehicle characterized by the above. 2. The auxiliary power supply device for a vehicle according to claim 1, further comprising a voltage monitoring circuit that shuts off a power supply path to the socket when the output voltage of the vehicle-mounted battery becomes equal to or lower than a set lower limit voltage. .. 3. The vehicle auxiliary power supply device according to claim 2, further comprising a reset switch for canceling an energization path interruption state by the current monitoring circuit and the voltage monitoring circuit.