JPH0418919Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a power supply circuit for an electrical device for an automobile that controls power supply to various electrical loads via a key switch activated by key operation. be.

(Prior Art) From the standpoint of safety, power is supplied to various electrical loads mounted on an automobile via a key switch operated by a key operation by a driver. There are various types of electrical loads installed in this automobile, but in terms of key switch operation, they can be broadly classified into at least the following three types. That is, the first is an electrical load necessary for engine operation, such as a spark plug. The second is an electric load, which is a starter motor, for driving the engine, that is, for applying the driving force required for complete explosion from the engine stopped state as an external force. The third is
There are many types of electrical loads that are not directly related to the engine, such as air conditioning fans, radiator fans, and anti-fogging hot wires.

In order to control the power supply to the various electrical loads as described above, the key switch has at least three types of contacts depending on the type of electrical load. In other words, an operating contact (also called the first ignition contact, hereinafter referred to as 1IG) for the electrical load for engine operation, a starting contact for the electrical load for engine driving, and a contact for electrical loads unrelated to the engine. (referred to as a second ignition contact, hereinafter referred to as the second IG). The key switch itself is configured to be able to take at least an on position and a starter position in addition to the off position, and in the starter position, the first IG and the starting contact are closed for engine drive (external force application) and operation. At the same time, the second IG is opened because the electric power required to start the engine is large. In addition, in the on position, no external force is required to drive the engine, so the starting contact is opened, the first IG is closed, and the second IG is also closed in order to continue operating the engine. It is becoming more and more like this.

For the 2nd IG as mentioned above,
As shown in the publication, a large number of electrical loads are connected, but in the case described in this publication, the power supply to the radiator fan and the air conditioning fan is controlled by the second IG. It's summery.

(Problem to be solved by the invention) However, when the second IG performs power supply control to a large number of electrical loads, when the key switch is turned off, there is a back emf from some of the electrical loads that try to continue operating due to inertia. Other electrical loads may be activated by the electric power, and depending on the type of electrical load that is activated, a situation may occur in which the driver feels uncomfortable. That is, for example, when the radiator fan and the air conditioning fan are both operating and the key switch is turned off, the radiator fan, although under a heavy load, will continue to rotate by inertia even after the power supply is stopped. The air conditioning fan with a small load tries to stop quickly, but due to the rotation of the radiator fan due to inertia, the radiator fan acts as a generator, and the above-mentioned back electromotive force is generated.
The air conditioning fan was to continue operating for some time after the key switch was turned on.

One way to solve such problems is to
Although it is conceivable to provide a plurality of second IGs, in this case the key switch becomes complicated and large, which is not preferable due to constraints on its placement position.

Therefore, the purpose of the present invention is to effectively utilize the conventional key switch without increasing the number of second IGs in the key switch, and to perform the same function as the second IG, that is, the ON position of the key switch. The object of the present invention is to provide a power supply circuit for an electrical device for a motor vehicle, which can form contacts that are closed and open at the starter position.

(Means and actions for solving the problem) In order to achieve the above-mentioned purpose, in the present invention, the first IG and the starting contact are used to provide the function of the second IG. The second IG is a conventional relay for controlling power supply to electrical loads unrelated to engine operation. Specifically, the relay coil of this relay is connected in series to the first IG (operating contact) and also connected between the first IG and the starting contact.

With this configuration, when the key switch is in the on position, the 1st IG (operating contact)
Since the starting contact is opened at the same time as the relay is closed, the relay is activated or closed. Furthermore, when the key switch is set to the starter position, both the 1st IG and the starting contact are closed, but in this case, battery voltage acts on both ends of the relay coil, and no potential difference occurs. , Therefore, a relay will be opened.

In this way, the relay is activated under exactly the same conditions as the second IG of the key switch, so this relay can be used to control the power supply to, for example, an air conditioning fan, and the second IG of the key switch can be used to control the power supply. For example, by controlling the power supply to the radiator fan, the above-mentioned problem caused by the back electromotive force can be solved.

(Embodiments) Examples of the present invention will be described below with reference to the attached drawings.

In the figure, A is a key switch, which has at least three contacts: a first IG1, a second IG2, and a starting contact 3, which are operating contacts, and is used to open and close each contact 1, 2, and 3. Accordingly, the battery B is used as a power source to control power supply to various electrical loads. This key switch A can be set to an off position, an on position, and a starter position by key operation by the driver. In the on position, the first IG1 and the second IG2 are closed and the engine starts. In the starter position, the first IG1 and the starting contact 3 are closed, and the second IG2 is opened.

An ignition device 4 as an electrical load necessary for engine operation is connected in series to the first IG 1, and a relay coil 5 of a relay C and a water temperature switch 6 are also connected in series. The water temperature switch 6 is closed when the engine cooling water temperature reaches a predetermined temperature or higher.
Although shown in a simplified manner, the spark plug is ignited at a predetermined timing when energized. As a result, when the first IG1 is closed, the ignition device 4 is energized, and
Relay contact 8 of relay C is closed on condition that water temperature switch 6 is closed.

A radiator fan, that is, a radiator motor 7, which serves as an electrical load unrelated to the drive and operation of the engine, and a relay contact 8 of the relay C are connected in series to the second IG2. Therefore, when the second IG 2 is closed, on condition that the water temperature switch 6 described above is closed, the radiator motor 7 is energized and driven, thereby reducing the engine (cooling water). is cooled. When the temperature of the engine falls below a predetermined temperature, the water temperature switch 6 is opened and the radiator motor 7 is automatically stopped.

D in the figure is a starter device for driving the engine.
The starter motor 9 includes a starter motor 9, a coil 10 for intermittent transmission of power from the starter motor 9 to the engine (output shaft), and a relay E for controlling power supply to the starter motor 9 and the coil 10. The coil 10 connects the starter motor 9 to the engine output shaft when it is energized, and disconnects this connection when it is demagnetized. The relay E is composed of a relay contact 11, a starting coil 12 and a holding coil 17 for the relay contact 11, and when the starting coil 12 is excited, the relay contact 11 is closed, and the holding coil 17 is closed. When energized, this closed state is maintained assuming that the relay contact 11 is closed, and further, when both coils 12 and 17 are demagnetized, the relay contact 11 is opened.
Both coils 12 and 17 are magnetized when receiving a battery voltage, and are substantially demagnetized when receiving a voltage smaller than the battery voltage. In addition, the resistance value of the holding coil 17 is the same as that of the relay coil 1 described later.
It is considered that the resistance value is sufficiently small compared to the resistance value of No. 6.

The starter motor 9, coil 10 and relay contact 11 are connected in series with each other, and the key switch A
It is connected to battery B by bypassing. The starting coil 12 of the relay E has one end connected to the starting contact 3 and the other end connected between the coil 10 and the relay contact 11. Further, the holding coil 17 is connected to the starting contact 3.

In the figure, F is an air conditioning fan as an electrical load unrelated to the drive and operation of the engine, and this fan includes a fan motor 13 and an air volume changeover switch 14 including a variable resistor. This fan motor 13 and changeover switch 14 are connected to the relay G
The relay contacts 15 and 15 are connected in series to the battery B, bypassing the key switch A. Thereby, on condition that the relay contact 15 is closed, the fan motor 13 can be rotated at a desired number of rotations (air volume) by operating the changeover switch 14. Note that the off contact of this changeover switch 14 is omitted from illustration.

The relay G has its relay contact 15 closed when its relay coil 16 is excited, and this relay G is configured to perform the same function as the second IG2. That is,
One end 16a of this relay coil 16 is connected to the first IG1
The other end 16b is also connected to the starting contact 3.

In addition, 18-22 in the figure are fuses.

In the above configuration, when the key switch A is set to the starter position, the first IG1 and the starting contact 3 are closed, and the second IG2 is opened. By closing this starting contact 3, the battery B
voltage is applied to the starting coil 12 and the relay contact 11 is closed. As a result, current flows through the relay contact 11 to the coil 10 and the starter motor 9, and an external force for driving the engine is applied. At this time, since the first IG1 is closed, the ignition device 4 is ignited, and the engine is started (completely exploded) together with the application of the external force.
Since the holding coil 17 is also energized while the starting contact 3 is closed, the relay contact 1
1 is kept closed.

In the starter position described above, the radiator motor 7 does not operate because the second IG 2 is open. In addition, the relay coil 16 of the relay G has both ends 1
Since the same voltage from battery B acts on both 6a and 16b via the first IG1 or the starting contact 3, no current flows and the relay contact 15 is opened. As a result, the air conditioning motor 13 will also not operate. In this way, when the starter motor 9 is driven through which a large current flows, the radiator and air conditioning motors 7 and 13, which are electrical loads unrelated to engine operation, do not operate.

After starting the engine, when the key switch A is set to the on position, the starting contact 3 is opened and the first IG1 and the second IG2 are closed. As a result, as is clear from the above explanation, the radiator motor 7 is operated as appropriate depending on the engine cooling water temperature, and the relay contact 15 is also closed, allowing the air conditioning motor 13 to be operated freely as desired. I can do it. At this time, voltage is applied from the first IG 1 to the starting coil 12 and the holding coil 17 via the relay coil 16, but the applied voltage acting on both coils 12 and 17 is applied via the relay coil 16. It becomes small. As a result, both coils 12 and 17 are substantially demagnetized, relay contact 11 is opened, and starter device D does not operate at all.

When the key switch A is turned to the OFF position while both the motors 7 and 13 are energized, the energization to all electrical loads is cut off, as is well known. At this time, the radiator motor 7 continues to rotate for a while due to inertia and generates a back electromotive force, but the air conditioning motor 13
Since there is no connection to the motor, the motor immediately stops without being affected by the counter electromotive force.

Although the embodiment has been described above, the electric load connected to the second IG2 and the relay G (relay contact 15)
An appropriate electrical load can be selected as the electrical load to be connected to. In this case, electrical loads that generate back electromotive force, such as the radiator motor 7, and electrical loads, such as the air conditioning motor 13 or room lamps, that may give the driver a sense of discomfort when receiving this back electromotive force, are
The second IG2 and the relay G may be connected separately. In addition, electrical loads that will not cause discomfort to the driver even if they receive back electromotive force, such as anti-fog hot wires, should be connected to either the 2nd IG2 or the relay G, depending on the contact capacity, etc. Bye.

Although omitted in the explanation, the key switch A may be one that can take a separate accessory position and has an accessory contact that is closed both in the accessory position and the on position. For example, a radio or the like is connected to the contact.

(Effects of the invention) As is clear from the above, the invention has the following effects:
While keeping the structure of the key switch as conventional, this key switch can be effectively utilized to obtain the second IG function of the key switch.
As a result, a plurality of electrical loads can be placed in a relationship in which they do not exert the influence of back electromotive force on each other.

In particular, with the present invention, it is sufficient to effectively utilize relays for electrical loads unrelated to engine drive and operation, and simply connect the relay coils to the operating contacts and starting contacts of the key switch. In addition to being extremely simple to configure, it is also extremely advantageous in terms of cost.

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of the present invention. A... Key switch, B... Battery, D...
Starter device, G... Relay, 1... 1st IG (operating contact), 3... Starting contact, 4... Ignition device,
7...Radiator motor, 9...Starter motor, 13...Air conditioning motor, 15...Relay contact, 16...Relay coil.

Claims (1)

[Scope of Claim for Utility Model Registration] The key switch includes an operating contact for controlling power supply to an electrical load for engine operation, a starting contact for controlling power supply to an electrical load for driving the engine, and a starting contact for controlling power supply to an electrical load for engine operation. and a second ignition contact for controlling power supply to an electrical load that is not in use, and is capable of taking a starter position and an on position, and in the starter position, the operating contact and the starting contact are closed. On the other hand, the second ignition contact is set to be opened, and in the on position, the second ignition contact and the operating contact are closed, while the starting contact is set to be opened. A power supply circuit for an electrical device for an automobile set in A power supply circuit for an electrical device for an automobile, characterized in that the power supply circuit is connected in series with the driving contact and the starting contact.