JPH04111296U - Blower motor control device for automotive air conditioners - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the power consumption and heat generation of the transistor that controls the current to the blower motor, and to eliminate abnormal noise. [Configuration] An analog control circuit 7 that controls the current to the blower motor 2 by changing the base current of the transistor 3, and an analog control circuit 7 that controls the current flowing to the blower motor 2 by changing the base current of the transistor 3. The analog control circuit 7 is operated at low speeds, and the duty control circuit 8 is operated at high speeds.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a blower motor control device for an automobile air conditioner.

0002

[Conventional technology]

Conventionally, as shown in FIG. 2, a blower motor that drives a blower 1 of an automobile air conditioner is used. The rotation of the transistor 2 is controlled by the transistor 3, but there are two ways to do this: be. The first is by changing the base current Ib of transistor 3. This is a method of controlling the vector current, that is, the current flowing to the blower motor 2.

0003 In this control, heat is generated in the transistor 3, and as shown by the solid line in FIG. Power consumption is at its maximum in the medium speed range where the motor voltage is medium. This power dissipation causes the transistor to Heat generation occurs in the controller 3. Therefore, a heat sink is attached to transistor 3. There is. In order to enhance the heat dissipation effect, the transistor 3 is located near the blower 1. The airflow from the blower 1 flows along the heat sink. transition As shown by the broken line in Figure 3, the amount of heat generated by Star 3 has almost the same tendency as the power consumption. However, the maximum amount of heat generated occurs at a speed slightly lower than power consumption. This is in the high speed range The airflow caused by the high-speed rotating blower 1 promotes the heat dissipation effect of the heat sink of the transistor 3. This is to advance.

Secondly, as shown in FIG. 2, the transistor 3 is switched by changing the time ratio (hereinafter referred to as duty ratio) of applying the input voltage V _i to the base within a certain period of time. In this method, the blower motor 2 is operated and the current to the blower motor 2 is turned on and off. That is, the duty ratio is set small when the speed is low, and the duty ratio is set large when the speed is high.

[0005]

[Problem that the idea aims to solve] However, in the device according to the first method, the heat sink of the transistor 3 is large. As a result, the air flow from blower 1 is obstructed by this heat sink, resulting in a decrease in air volume. There was a problem that wind noise was generated. Also, in the device using the second method, , at low speeds, transistor 3 turns off immediately after turning on, causing a rattling sound. There was a problem. The purpose of this invention is to solve these problems, and to reduce the power consumption of transistors. A blower motor control device for automotive air conditioners that generates little heat and noise, and does not produce abnormal noise. The purpose is to provide the following.

[0006]

[Means to solve the problem]

In order to achieve the above object, the present invention uses a transistor to connect the blower motor. Transistors are used in blower motor control devices for automotive air conditioners that control current. An analog device that controls the current to the blower motor by varying the base current of the blower motor. control circuit and the time rate at which the input voltage is applied to the base within a certain period of time. A duty control circuit that controls the current to the blower motor on and off by The analog control circuit operates at low speeds, and the duty cycle operates at high speeds. It is designed to operate a control circuit.

[0007]

[Effect]

At low speeds, the transistors are driven by analog control circuitry, reducing power consumption and Although heat is generated, since the collector current is small, power consumption and heat generation are low. Ma In addition, at high speeds, the transistor is driven by the duty control circuit, so the consumption is low. No electricity is generated and no heat is generated.

[0008]

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a blower motor control device for an automobile air conditioner according to the present invention. , in the figure, 1 is the blower, 2 is the blower motor, and 3 is the current to control the blower motor 2. The control transistor, 4, controls the rotation of the blower from low to high speed by lever operation, etc. This is a blower speed switching device that can be switched in stages. The control device includes a control mode discrimination circuit 5, an IC switch 6, and an analog control circuit. 7 and a duty control circuit 8.

[0009] The control mode discrimination circuit 5 is switched and selected by the blower speed switching device 4. It is determined whether the selected rotation control mode of the blower motor 2 is low speed or high speed, and If so, switch the IC switch 6 to the A contact side and switch the analog control circuit 7 to the A contact side. Output the operating signal, and if the speed is high, switch the IC switch 6 to the B contact side and , and outputs an operating signal to the duty control circuit 8. The IC switch 6 switches based on the signal from the control mode discrimination circuit 5. When the A contact is closed, the output terminal of the analog control circuit 7 and the transistor The base of the star 3 is connected through a resistor 9. Also, the B contact When closed, the output terminal of the duty control circuit 8 and the base of the transistor 3 are connected to each other. It is designed to be connected via resistor 9.

0010 The analog control circuit 7 connects a resistor R and a controller from point P of the power supply circuit of the blower motor 2. Receives feedback of the collector voltage value via an integrating circuit 10 consisting of a capacitor C. At the same time, by changing the base current of transistor 3, the collector current can be controlled. The blower speed selected by the blower speed switching device 4 is maintained. ing. The duty control circuit 8 is an integrating circuit consisting of a resistor R and a capacitor C from point P. While receiving feedback of the collector voltage value through 11, the input voltage to the base is The collector current is turned on and off by changing the duty ratio of The blower speed is maintained at the specified blower speed.

[0011] In the blower motor control device having the above configuration, the blower speed switching device 4 When the lower speed mode is selected, the control mode discrimination circuit 5 discriminates this and the I Switch the contact point of the C switch 6 to the A side, and operate the analog control circuit 7. let As a result, the base current of the transistor 3 is adjusted by the analog control circuit 7. the collector current is controlled so that blower 1 remains in the selected slow rotation mode. be done. In this low-speed rotation mode, the collector current is analog-controlled, so the consumption Electric power is generated, but its value is very small because it is slow and the collector current value is small. It is small in size and generates little heat. Also, since it is not duty controlled, the rattling sound will be Does not occur.

0012 Next, when the high speed mode is selected by the blower speed switching device 4, the control When the code discrimination circuit 5 discriminates this and switches the contact of the IC switch 6 to the B side, Both operate the duty control circuit 8. As a result, the input voltage to the base of the transistor 3 is increased by the duty control circuit 8. The collector current is controlled on and off by adjusting the duty ratio of the blower. 1 remains in the selected high speed rotation mode. In this high-speed rotation mode, the collector current is controlled on and off, so the transformer The resistor 3 consumes no power and does not generate heat.

[0013] In this way, the power consumption and heat generation of transistor 3 are low at low speeds, and low at high speeds. Since this does not occur at high speeds, the heat sink of the transistor 3 can be made smaller. child Therefore, the transistor 3 has been miniaturized, and even if it is installed near the blower 1, it is not covered by the heat sink. There are no problems such as wind noise or reduction in air volume.

[0014]

[Effect of the idea]

As is clear from the above explanation, according to the present invention, the power consumption of the transistor The transistor heat sink can be made smaller, so the heat sink can be There is no wind noise or reduction in air volume. Also, at low speeds, the transistor Since the motor is analog controlled rather than duty controlled, there will be no wobbling. It has the following effects.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram of a blower motor control device for an automobile air conditioner according to the present invention.

FIG. 2 is a control circuit diagram of a conventional blower control device.

FIG. 3 is a diagram showing the relationship between blower voltage, power consumption, and heat generation amount.

[Explanation of symbols]

2...Blower motor, 3...Transistor, 7...
Analog control circuit, 8...Duty control circuit.

Claims (1)

[Scope of utility model registration request] 1. A blower motor control device for an automobile air conditioner that uses a transistor to control current to the blower motor, comprising: an analog control circuit that controls the current to the blower motor by changing the base current of the transistor; and a duty control circuit that controls the current to the blower motor on and off by changing the time ratio of applying an input voltage to the base, and operates the analog control circuit at low speeds and operates the duty control circuit at high speeds. A blower motor control device for an automobile air conditioner, characterized in that the blower motor control device is adapted to operate.