JPH0986159A - Air cleaner for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a relay, to reduce cost and to save a space and to improve assembly workability of a circuit substrate and a harness by constituting a circuit by using a resistor for pulling up in a device to automatically stop a motor for a fan at the time when a door switch is switched on. SOLUTION: When a vehicle door is closed and a door switch 5 is switched off, electric potential of one end (connecting point 10) of a pull up resistor 9 becomes base electric potential of a transistor Tr4 and as it is larger than emitter electric potential Tr4 is not switched on, there is no collector output of Tr4, and a control part 2 controls a motor 1 for a fan with a current fan mode. In the meantime, when the door is opened and the door switch 5 is switched on, a base electric current of Tr4 flows as an electric current flows to the door switch 5 from the one end of the pull up resistor 9. Consequently, Tr4 is switched on and the collector electric current (motor stop signal) is output to the control part 2, and the motor 1 for the fan is forcibly stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a control circuit for an automobile air cleaner.

[0002]

2. Description of the Related Art As an example of various functions required for controlling an air purifier for an automobile, for example, each time a push button is pressed, the mode of the fan is changed from HI to LO to OFF to HI.
, The fan stops automatically when the car door is opened, and the motor automatically stops when the motor locks.

FIG. 2 is a schematic diagram of a control circuit of a conventional automobile air purifier for fulfilling such requirements. Note that, here, since the main purpose is to improve the circuit for automatically stopping the fan when the vehicle door is opened, the circuit for automatically stopping the motor when the vehicle is locked is omitted.

A motor 1 for driving a fan (not shown) is controlled by a control unit 2, and the control unit 2 has an operation switch 3
(Push button) is connected. The control unit 2 is composed of an appropriate logic circuit, etc.
Each time the button is pressed, the voltage applied to the motor 1 is changed and the fan mode is sequentially switched from HI to LO to OFF to HI.

A transistor 4 is connected to the control unit 2. The transistor 4 is turned on when the base current a flows through the transistor element Q due to the switching action, and outputs a signal (collector current) to the control unit 2. The controller 2 that receives the signal from the transistor 4 stops the motor 1. The opening / closing detection portion of the vehicle door is composed of a door switch 5 and a relay 6. The door switch 5 has a large resistance value structurally, and one end thereof is grounded and the other end thereof is connected to a vehicle-mounted battery via a coil portion of the relay 6. The contact of the relay 6 has one end grounded and the other end connected to the base of the transistor 4. The transistor 4 has a built-in resistor for protecting the transistor element Q in advance. The diode 7 is for protecting the transistor 4, and the capacitor 8 is for absorbing surge.

When the vehicle door is opened and the door switch 5 is turned on, a current b flows through the coil portion of the relay 6 and the contact of the relay 6 is closed. As a result, the base current a flows through the transistor element Q to turn on the transistor 4, and the transistor 4 outputs a motor stop signal (collector current) to the control unit 2. In this way, when the vehicle door is opened, the motor 1 is automatically stopped and the battery is prevented from running out.

[0007]

However, in such a conventional circuit configuration, since the relay 6 is used for the opening / closing detection portion of the vehicle door, it is disadvantageous in terms of cost and space. . That is, the relay belongs to an expensive class among electronic components, and the increase in cost is unavoidable, and the relay itself is a relatively large component, and thus requires a large space when assembling a circuit. Especially when an external relay is used, it must be connected to a harness, which makes it difficult to assemble the circuit board and harness. In addition, it is necessary to push a large relay with a harness into a predetermined space of the air purifier unit, which makes it difficult to assemble the entire air purifier unit.

As a configuration without using the relay 6, for example, the transistor 4 and the door switch 5 may be directly connected. However, in this case, since the base current is very small, the door switch 5 is not used. There is a case where the oxide film on the contact point is not broken and the transistor 4 does not turn on.

The present invention has been made to solve such a problem, and is for an automobile having a function of detecting opening / closing of a vehicle door and automatically stopping a motor without using a relay. The purpose is to provide an air purifier.

[0010]

In order to achieve the above object, the present invention relates to an automobile air purifier in which a fan driving motor is automatically stopped when a vehicle door switch is turned on. , A controller for controlling the motor, a transistor for outputting a motor stop signal to the controller when it is turned on by a switching action, and a serial connection between the door switch whose one end is grounded and an in-vehicle power source. A pull-up resistor, and the base of the transistor is connected to a connection point of the door switch and the resistor.

In the circuit thus constructed, when the vehicle door is closed and the door switch is turned off, the potential at one end (coupling point) of the pull-up resistor (pull-up resistor) is the vehicle-mounted power source. Since this potential becomes the base potential of the transistor, the transistor does not turn on.
On the other hand, when the vehicle door is opened and the door switch is turned on, a current flows from one end (coupling point) of the pull-up resistor to the door switch, the oxide film of the door switch is broken, and the base current of the transistor flows. Therefore, the transistor is turned on. When the transistor turns on, a motor stop signal is output from the transistor to the controller, and the controller stops the motor and turns off the fan.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a control circuit of an automobile air cleaner according to an embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals, and like FIG. 2, a circuit for automatically stopping the motor at the time of locking is omitted.

Like the conventional circuit shown in FIG. 2, this circuit has a motor 1 for driving a fan (not shown) and a control unit 2 for controlling the motor 1. The control unit 2 has an operation switch 3 ( Push button) is connected. The control unit 2 is composed of an appropriate logic circuit and the like, and every time the operation switch 3 is pressed, the voltage applied to the motor 1 is changed so that the fan mode is sequentially switched to HI → LO → OFF → HI. There is. The operation switch 3 is not limited to the push button, and it goes without saying that the operation switch 3 may be a dial type switch or a plurality of push buttons. In these cases, the desired fan mode is selected by turning the dial switch to the desired position or pressing the desired push button.

A transistor 4 is connected to the control unit 2. More specifically, the transistor 4 is composed of a transistor element Q and resistors R1 and R2 for protecting it (a so-called digital transistor in which a resistor is incorporated), and the collector of the transistor element Q is in the control unit 2. Connected and the emitter is connected to a given power source (for example,
5 V), and the base is connected to a connecting point of a pull-up resistor and a door switch, which will be described later, via a resistor R1 and a diode 7. When the base potential of the transistor 4 becomes higher than the emitter potential, the switching operation causes the base current a to flow in the transistor element Q to turn on.
A signal (collector current) is output to the control unit 2. The signal from the transistor 4 acts as a motor stop signal, and the control unit 2 receiving this signal is configured to stop the motor 1. The diode 7 is the transistor 4
Is connected to a capacitor 8 whose one end is grounded in order to absorb a surge.

Door switch 5 for detecting the opening and closing of the vehicle door
Has one end grounded and the other end connected to an in-vehicle battery (for example, 12V) as an in-vehicle power source through a pull-up resistor 9. That is, the pull-up resistor 9 is connected in series between the door switch 5 and the vehicle-mounted battery. The base of the transistor 4 is connected to the connection point 10 between the pull-up resistor 9 and the door switch 5 via the diode 7.

The pull-up resistor 9 has a function of facilitating the flow of the base current of the transistor 4 when the door switch 5 is turned on. By connecting such a pull-up resistor 9 as described above, The conventional relay can be eliminated and the transistor 4 can be turned on when the door switch 5 is turned on.

That is, when the vehicle door is closed and the door switch 5 is off, the potential of one end of the pull-up resistor 9 (that is, the connection point 10) is the same as that of the vehicle battery (12 V), and this potential is It becomes the base potential of the transistor 4. Therefore, since the base potential (12V) of the transistor 4 is higher than the emitter potential (5V),
The transistor 4 does not turn on. Therefore, transistor 4
There is no collector output of, and the control unit 2 controls the motor 1 in the current fan mode.

On the other hand, when the vehicle door is opened and the door switch 5 is on, a current flows from one end of the pull-up resistor 9 (connection point 10) to the door switch, and the oxide film of the door switch is broken. The base current of the transistor will flow. The resistance value of the pull-up resistor 9 is appropriately set in advance so that a current that breaks the oxide film of the door switch 5 flows. As a result, the base current of the transistor 4 when the door switch 5 is turned on flows through the door switch 5, and the transistor 4 is turned on. Therefore, the collector current (motor stop signal) is output from the transistor 4 to the control unit 2, and the control unit 2 forcibly stops the motor 1 and turns off the fan. In this way, when the vehicle door is opened, the motor 1 is automatically stopped and the battery is prevented from running down.

Therefore, according to the present embodiment, since the control circuit for automatically stopping the fan when the vehicle door is opened is constructed by using the pull-up resistor 9, the conventionally used relay can be eliminated. Therefore, cost reduction and space saving can be achieved. Further, since no relay is used, the workability of assembling the circuit board and the harness is improved, and the workability of assembling the entire air purifier unit is also improved.

[0021]

As described above, according to the present invention, since the circuit is configured by using the pull-up resistor, the relay can be eliminated, and the cost and space can be saved. Further, the workability of assembling the circuit board and the harness and the workability of assembling the entire air purifier unit are improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a control circuit of an automobile air cleaner according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a control circuit of a conventional automobile air cleaner.

[Explanation of Codes] 1 ... Motor 2 ... Control unit 4 ... Transistor 5 ... Door switch 9 ... Pull-up resistor 10 ... Coupling point

Claims (1)

[Claims] 1. An air cleaner for an automobile, wherein a fan driving motor (1) is automatically stopped when a door switch (5) of a vehicle is turned on. A control for controlling the motor (1). Section (2) and transistor (4) for outputting a motor stop signal to the control section (2) when turned on by a switching action
And a pull-up resistor (9) connected in series between the door switch (5) whose one end is grounded and an in-vehicle power source, and the base of the transistor (4) is connected to the door switch (5). An air purifier for an automobile, characterized in that it is connected to a connection point (10) between 5) and the resistor (9).