JPH0466725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air door control device for an automobile air conditioner, in which the air door is driven by a DC motor.

[Conventional technology]

It has also been proposed to drive the air door of an automobile air conditioner with a DC motor. In this case, there is an advantage that it is not affected by the operating state of the engine, compared to one that uses engine negative pressure as the drive energy source.

[Problem to be solved by the invention]

On the other hand, when using a DC motor, since the main body of the air conditioner, at least the air outlet, faces the passenger compartment, there is a problem that noise generated from the DC motor reaches the passenger compartment when the DC motor is operated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air door control device for an automobile air conditioner using a DC motor, which eliminates the above-mentioned noise problem.

[Means to solve the problem]

Therefore, the present invention focuses on the fact that the rotational vibration of a DC motor increases as the voltage applied to the DC motor increases, and the voltage applied to the DC motor when driving an air door is changed from a small value to a low value. The DC motor is characterized in that the voltage is gradually increased until the door begins to move, and after the door begins to move, the voltage is stopped from increasing beyond a predetermined level, so that the DC motor is always driven with the minimum voltage.

A structural diagram of the present invention is shown in FIG. 3, in which an air door of an air conditioner for an automobile is designated by the reference numeral A. The air door A is driven by a drive means D that includes a DC motor.
is driven and displaced by the air duct B, thereby adjusting the rate of air flow passing through the heater core C in the air duct B.

An operation command means E is provided for generating an operation command signal when the air door A is to be driven manually or automatically, and in response to the operation command signal generated by the operation command means E, the signal generation means F is gradually activated. A signal is generated representing an increasing voltage level. The voltage applying means G receives a signal representing the voltage level from the signal generating means F and applies a voltage corresponding to the represented voltage level to the DC motor of the driving means D. A detection means H is connected to the drive means D, which generates a detection signal when the drive starts.
The generated detection signal is given to signal generation means F,
The signal generating means F stops increasing the voltage level upon receiving the detection signal.

In short, the signal generating means F is designed to generate a signal representing a voltage level that gradually increases and stops from the time it receives the operation command signal until it receives the detection signal, and the voltage represented by this signal is The voltage is applied via the voltage applying means G to the DC motor of the driving means.

Note that the signal generating means F and, if necessary, part of the operation commanding means E and the detecting means H can be realized by a microcomputer. Detection means H
can also serve as a position signal generator representing the position of the output rod in the drive means D, in which case:
The signal generating means F may be arranged to extinguish the signal representative of said voltage level in order to stop the drive means when the air door reaches the desired position. In addition, the operation command means E can be configured as a separate position signal generator that generates a signal representing the target position, corresponding to the employment of a position signal generator, but the operation command means E can also be configured as a separate position signal generator that generates a signal representing the target position, or a single position signal generator that simply displaces the air door. It is also possible to use a type that generates a signal.

〔Example〕

FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, reference numeral 1 is a target position signal generator that generates a resistance value representing the target operating position of the air door.The resistance value Rs is the minimum when the air door is closed, and the resistance value Rs is the maximum when the air door is opened. It is determined that it will become. Signal generator 1 has A
-D converter 2 is connected, and a digital value signal 2A corresponding to a voltage division ratio with a series resistor having a predetermined resistance value built in A-D converter 2 is applied to microcomputer 3. Note that "closing" and "opening" the air door are relative terms, and which one is called "closed" or "opened" can be determined as appropriate. Further, in this embodiment, the target position signal generator 1 corresponds to the operation command means in the present invention, and the A-D
The resistance value Rs converted from analog to digital by the converter 2 corresponds to the operation command signal.

The drive device 4 includes a DC motor 5, and the DC motor 5 drives the air door via a speed reduction mechanism (not shown). Here, it is assumed that the air door adjusts the temperature of the air blown from the air conditioner by continuously changing its displacement. In the drive device 4, a position signal generator 6 is provided which corresponds to the displacement of the output rod of the DC motor 5. The signal generator 6 generates a resistance value Rp corresponding to the actual position of the air door. This resistance value Rp is minimum when the air door is closed and maximum when it is open.

An A-D converter 7 is connected to the signal generator 6,
A digital value signal corresponding to a voltage division ratio with a series resistor having a predetermined resistance value built in the A-D converter 7 is given to the microcomputer 3.
Note that the AD converters 2 and 7 may be of a type that selectively receives input signals and performs AD conversion. Further, in this case, the microcomputer 3 may be of a type having a built-in A/D conversion function.

The microcomputer 3 compares the target position signal of the target position signal generator 1 and the actual position signal of the actual position signal generator 6 according to a preset control program, and when there is a difference between the positions indicated by the two signals, A drive signal is given to the DC motor drive circuit 8 so as to eliminate the deviation. The drive signal consists of a code signal indicating the rotation direction of the DC motor 5 and a level signal indicating the applied voltage. In the illustrated DC motor 5, the applied voltage V is expressed with a positive sign in the direction toward point b from point a, and a negative sign in the opposite direction. In this embodiment, the DC motor drive circuit 8 constitutes voltage application means.

The applied voltage V and the sign signal are given as digital value output signals from the microcomputer 3 to the drive circuit 8, which includes a current direction switching circuit, a D-A converter, and a current whose conductivity is continuously adjusted. The current value switching circuit determines the direction of the current applied to the DC motor 5 using the sign signal, and the digital value signal representing the applied voltage V controls the D-A converter and the current value adjustment circuit. The voltage V applied to the DC motor 5 through the circuit
Adjust.

FIG. 2 shows an outline of the control program of the microcomputer 3. This control program is designed to be periodically executed by one computer that centrally processes various control functions of the automobile air conditioner. computer 3
In this control program, in step 101, the position signals from both position signal generators 1 and 6 are converted into digital value signals representing resistance values Rs and Rp, respectively.
It is input from the D converters 2 and 7 and temporarily stored in a temporary memory. Next, in step 102, the actual position signal Rp of the air door at that time is stored as data A.

At step 103, the actual position data Rp and the target position data Rs are compared, and if the actual position data Rp is close to the target position data Rs, the process jumps to step 117 and the process is stopped. If the two data are far apart, the processing from step 104 onwards is executed. In step 104, data indicating the initial value of the voltage V applied to the DC motor 5 is set, and a digital value signal corresponding to the initial data is output to the drive circuit 8. Although the initial data here represents 0 volts for convenience of explanation in relation to the code signal, it can be replaced with any absolute value and a code signal indicating the direction to be driven.

In step 105, it is determined which of the target position data Rs and the actual position data Rp is larger, and if Rs is smaller (when the air door should be closed than that position), the process of step 111 is executed. , when Rs is large, the process of step 106 is executed. In this embodiment, the control processing from step 105 to step 106 and the control processing from step 105 to step 111 constitute a signal generating means. Steps 106, 107, and 108 and steps 111, 112, and 113 are substantially equivalent processes, except that the direction in which the air door is driven is different. Describing step 106 and subsequent steps as a representative example, the voltage level V to be applied to the DC motor 5 is increased by a predetermined unit, for example, 1 volt.

In step 107, the actual position data Rp is A-D again.
It is input from the converter 7 and it is determined whether the value A has increased with respect to the initially stored value A, that is, whether the air door has started to be driven by the DC motor. Before the air door starts moving, the actual data Rp and the initial data A are equal, so
Proceeding to step 114, it is determined whether or not the applied voltage level V exceeds a preset maximum value, for example 12 volts. If it does not, step 114A waits for a certain period of time, and the process from step 105 is repeated again.

As a result, when the DC motor 5 starts moving,
In step 108, the applied voltage level is increased by 1 volt for added safety, and then in step 109.
Proceed to. That is, in this embodiment, 1 volt is not considered an increase in voltage beyond a predetermined level. Thus, the voltage applied to the DC motor 5 is gradually increased, and once the air door begins to be driven, the increase in the applied voltage is stopped. Step 111
The process at ~113 is similar, only the sign of the applied voltage level V becomes negative and the absolute value is gradually increased until the air door begins to be driven.

In step 109, input the actual data Rp again,
It compares this with the target position data Rs and waits until they almost match. Eventually, when both data match, in step 110, a control signal for stopping the DC motor 5 in the drive circuit 8, that is, an output signal for setting the applied voltage to 0 volts, is generated. In this way, the drive device 4 is driven to the position set by the target position signal generator 1 with the minimum necessary applied voltage.
Stop. In this embodiment, the control processing from step 107 to step 109 and the control processing from step 112 are
The control processing from step 109 to step 109 and the actual position signal generator 6 constitute a detection means.

If the DC motor 5 does not start moving before reaching the maximum set value of 12 volts even if the applied voltage to the DC motor 5 is increased, the applied voltage level V
is set to 0 volts. In addition, if necessary, a warning light can be connected as an output device of the microcomputer 3.
The warning light may be turned on by a command step shown in step 116.

〔Effect of the invention〕

According to the present invention described above, by driving the DC motor with the small amount of power supplied when the DC motor starts operating, even if the load on the air door changes due to the air flow rate or changes over time, this Accordingly, it is possible to operate the automobile air conditioner with the lowest noise.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a flowchart showing an overview of the control program of the microcomputer in Fig. 1, and Fig. 3 is a conceptual explanatory diagram showing the structure of the present invention. It is. 1...Target position signal generator forming the main part of the operation command means, 3...Microcomputer, 4...Driving device, 5...DC motor, 6...Real position signal generator forming the main part of the detection means , 8... A DC motor drive circuit forming the main part of the voltage application means.

Claims (1)

[Scope of Claims] 1. An air conditioner for an automobile having an air door driven by a DC motor, comprising: an operation command means for outputting an operation command signal for commanding driving of the air door; and a response to the operation command signal. signal generating means for generating a signal representing a drive voltage that gradually increases; voltage applying means for applying a drive voltage to the DC motor according to the signal generated by the signal generating means; and driving the DC motor. An air door control for an air conditioner for an automobile, characterized in that the air door control includes: a detection means for detecting a state and stopping an increase of the signal generated by the signal generation means beyond a predetermined level after the DC motor starts driving. Device.