JPS62234716A - Control circuit of servomotor - Google Patents

Abstract

PURPOSE:To eliminate the need for using a particular rotation limiting switch by making a position control means output a stop signal for a servomotor when the arrival of said servomotor at at least one stop position within an operating range is detected by detecting means. CONSTITUTION:After air is cooled by passing through an evaporator 9, the quantity of air is regulated by a temp. regulating damper 2 when passing through a heater core 10 and, thereby, its temp. is controlled. The damper 2 is driven by a servomotor 101, and its operating position is detected by a potentiometer 102. And, the servomotor 101 is feedback controlled by the position control part A of a control device 1 according to the output of the potentiometer 102. Also, an operation limiting means B is provided on the control device 1, which makes the position control part A output a servomotor stop signal when the arrival of the servomotor 101 at a defined stop position is detected from the output of the potentiometer.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a servo motor control circuit that controls the stop position of a servo motor, and is applicable to various types of servo motors, such as servo motors for driving dampers of vehicle air conditioners. It can be used in servo motor control circuits.

[Conventional technology]

Conventionally, the servo motor was stopped at the upper or lower limit of the operating angle of the servo motor in 1988-401.
The one disclosed in Japanese Patent No. 11 is generally known.

The operating angle of the servo motor is controlled by the output of a potentiometer that detects the operating angle.The upper and lower limits of the output shaft of the servo motor consist of a patterned electrode on a printed circuit board and a slider that slides on this. A rotation limit switch was used to cut off the current flowing to the servo motor and stop the servo motor.

[Problem that the invention seeks to solve]

However, in the conventional servo motor control circuit described above, the servo motor is equipped with a rotation limit switch consisting of a pattern electrode on a printed circuit board that cuts off the current flowing to the motor at the stop position, and a slider that slides on the pattern electrode on a printed circuit board. There is a problem in that it must be established.

In view of this problem, an object of the present invention is to provide a control circuit for a servo motor that does not include a rotation limit switch.

[Means for solving problems]

In order to achieve the above-mentioned objects, the present invention includes a potentiometer that works in conjunction with a servo motor, detects the operating position of the servo motor, and outputs it electrically; and a potentiometer that operates the servo motor according to the output of the potentiometer. A control circuit for a servo motor comprising: a position control means for controlling the position to an arbitrary target position within the operating range, wherein the potentiometer indicates that the servo motor has reached at least one stop position within the operating range. A technical means is adopted in which an operation limiting means is provided for detecting from the output of the servo motor and outputting a stop signal of the servo motor to the position control means.

[Effect]

In the device of the present invention, the potentiometer detects the operating position of the servo motor and outputs this electrically.

The position control means receives this output. Then, the servo motor is operated so that the operating position of the servo motor corresponding to this output becomes an arbitrarily determined target position, and when the servo motor reaches the target position, it is stopped.

The operation limiting means receives the output of the potentiometer, and when the operating position of the servo motor corresponding to this output reaches at least one stop position predetermined in addition to the target position, it sends a servo motor stop signal to the position control means. to stop the servo motor.

〔Effect of the invention〕

As is clear from the above, the device of the present invention consists of a pattern electrode on a printed circuit board and a slider that slides on the pattern electrode, and is provided with a rotation control switch that cuts off the motor current of the servo motor at the stop position of the servo motor. The servo motor can be stopped at its stop position without any trouble.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In this embodiment, the present invention is applied to the control of a servo motor that controls a temperature control damper of a vehicle air conditioner. Control the servo motor.

FIG. 1 is a configuration diagram of a vehicle air conditioner. The outline of the vehicle air conditioner will be explained below. The inside/outside air switching servo motor 3 drives the inside/outside air switching damper 4 to open either the outside air intake port 6 or the inside air intake port 5. The pro fan 7 is driven by a pro a motor 8, sucks in outside air or inside air from either of the intake ports 5 and 6, and sends the air to the evaporator 9 on the downstream side. The air that has passed through the evaporator 9 is dehumidified and cooled air. The temperature control damper is driven by the control device 1 of this embodiment. Heater core 10 heats air. The air that has passed through the evaporator 9 is separated by the temperature control damper 2 into air that passes through the heater core 10 and air that passes through the bypass passage 13.

The temperature of the downstream outlet is determined by the ratio of the reheated air passing through the heater core 10 and the temperature-reduced air passing through the bypass passage 13.

Therefore, the temperature adjustment damper 2 needs to be controlled to an arbitrary target position. For this purpose, the control device 1 is provided with a potentiometer 102 that detects the position of the temperature adjustment damper 2, that is, the operating position of the servo motor 101 that drives the temperature adjustment damper 2. The output of this potentiometer 102 causes the position control unit A to control the temperature control tamper 2.
The servo motor 101 is feedback-controlled so that the position is at an arbitrary target position.

At this time, since the movement of the temperature control damper is restricted at two stop positions, the maximum heating position 11 shown by the first dotted line and the maximum cooling position 12 shown by the solid line, the servo motor 10
1 also needs to be stopped accordingly. The operation limiter B detects these stop positions from the output of the aforementioned potentiometer 102, and stops the servo motor 1°1 via the position controller.

The air reheated to a predetermined temperature is blown into the vehicle interior from a predetermined outlet 16 or 17 by an outlet selection damper 15. This outlet selection damper 15 is driven by an outlet selection servo motor 14.

FIG. 2 shows a circuit configuration diagram of a first embodiment of the control device 1 for driving the temperature control damper of the vehicle air conditioner described above.

The configuration of the position control section A of the first embodiment will be described based on FIG. The servo motor 101 drives an output shaft, also not shown, via a speed reduction mechanism, not shown. A movable contact 103 of the potentiometer 102 slides on a resistor 104 in conjunction with this output shaft. The setting resistor 105 is set at a predetermined position by a vehicle occupant, and the voltage drop across the setting resistor 105 and the voltage drop across the potentiometer 102 are input to a first differential amplifier 106, and the difference between them is output.

This output is applied to the second differential amplifier 107 and the third differential amplifier 1.
It will be man-powered in 2008. The second differential amplifier 107 and the third differential amplifier 108 compare the output of the first differential amplifier 106 and the divided voltages of the voltage dividing resistors 109, 110, 111, ) or outputs a low level (hereinafter simply referred to as L). The output of the second differential amplifier 107 is input to the No. 1 terminal of the servo motor drive circuit 112, and the output of the third differential amplifier 108 is input to the inverter 11.
3 to the No. 2 terminal of the servo motor drive circuit 112. Nos. 6 and 7 of this servo motor drive circuit 112
The 10th power supply is input to the No. 4 terminal, and the No. 4 terminal is grounded. A servo motor lot is connected to the third terminal and the fifth terminal.

Below, the configuration of the operation restriction section B, which is the main part of the present invention, is as follows.
The explanation will be made based on FIG. 2 as well. The movable contact 103 of the potentiometer 102 described above is connected to the fourth differential amplifier 11
4 and a child terminal of the fifth differential amplifier.

A voltage dividing resistor 115 and a voltage dividing resistor 115 are connected to the fourth differential amplifier 114+ terminal.
A reference voltage divided by voltage dividing resistors 118 and 119 is input to one terminal of the fifth differential amplifier 117.
A reference voltage divided by the voltage is input.

The output of the fourth differential amplifier 114 is the servo motor drive circuit 1
The output of the fifth differential amplifier 117 is input to the second terminal of the servo motor drive circuit 1 through the second inverter 120.
It is input to the 1st terminal of 12.

The above is the configuration of the first embodiment, and the servo motor drive circuit 112 uses an integrated circuit TA8050P manufactured by Toshiba Corporation, but it may also be a circuit using transistors.

Note that the operation limiting means B is composed of a fourth differential amplifier 114, a fifth differential amplifier 117, a voltage dividing resistor that provides a reference voltage for these, and the like.

The operation of the first embodiment will be explained below.

First, in the above-described configuration, the position control section A is a known part. This position control unit A rotates the servo motor 101 to the position of the temperature adjustment damper set by the setting resistor 105, and the temperature adjustment damper corresponds to the setting value of the setting resistor 105 by the output of the potentiometer 102 that interlocks with the servo motor 101. When it is detected that the servo motor 101 has been driven to the specified position, the servo motor 101 is stopped. Servo motor drive circuit 1
Table 1 shows the truth table of the 12 input terminals, the 1st terminal, and the 2nd terminal, and the output terminals, 3rd terminal and 5th terminal. From the state shown in FIG.
When moved in one direction and an arbitrary target position is set, the voltage at one terminal of the first differential amplifier 106 increases. At this time, the voltage at the 10th terminal is lower than that at the 1st terminal because the potentiometer 102 has not moved yet. Then, the first differential amplifier 106 outputs the difference between these voltages as a negative voltage. Due to this output, the outputs of the second differential amplifier 107 and the third differential amplifier 108 become H, and the output of the third differential amplifier 108 is inverted by the first inverter 113. L is input to the No. H12 terminal, and the servo motor 101 is driven in the Max Coo1 direction. When the servo motor 101 rotates, the temperature adjustment damper 2 is driven.

Along with this, the potentiometer 102 force Qfax Co
It moves in the o1 direction, and this output voltage increases. Eventually, when the voltage becomes equal to the voltage of the setting resistor 105, the first differential amplifier 1
06 becomes a voltage between the reference voltage of the second differential amplifier 107 and the reference voltage of the third differential amplifier 108, the servo motor 101 stops, and the temperature control damper 2 stops at the target position. Even when the setting resistor 105 is moved in the Max hot direction, H and L are reversed from the above case, and the temperature adjustment damper 2 is similarly driven to the target position.

(Margins below) Table 1 Next, the operation of the operation restriction section B, which is the main part of the present invention in the first embodiment, will be explained. This operation limiter B is the temperature control damper 2
is set to the maximum cooling position (Max
cool) or the maximum heating position (Max hot
), the servo motor 101 is stopped.

When the setting resistor 105 is set to the Max cool position, the above-mentioned position control section A rotates the servo motor 101 to drive the temperature adjustment damper 2 to the Max cool position. The movable contact 103 of the potentiometer 102 is
When the movable contact 103 moves to a position corresponding to ax cool, the potential of this movable contact 103 becomes V. Fifth differential amplifier 1
17 is the voltage division between voltage dividing resistors 118 and 119, for example 4.5.
(V) and vl are compared, and when vI becomes higher, the output is inverted to lI mustard. This output is further inverted by the second inverter 120 to become H, and is input to the servo motor drive circuit 11202 terminal. Then, the output of the servo motor drive circuit 112 becomes the brake mode.
Servo motor 101 stops.

The setting resistor 105 is set to the Max hot position, the movable contact 103 of the potentiometer 102 moves, and the M
At the position corresponding to ax hot, this voltage becomes V2
become. The fourth differential amplifier 114 has voltage dividing resistors 115 and 11
6, for example, 1.5 (V), and when (2) becomes lower than 1.5 (V), the output is inverted from L to (3). This output is the servo motor drive circuit 1
The signal is input to the No. 1 terminal of the motor 101, and its output is set to the brake mode to stop the motor 101.

In this way, in the operation limiting section B of the first embodiment, when the voltage of the movable contact 103 of the potentiometer 102 becomes 4.5 (V) or higher, the fifth differential amplifier 117 detects this and stops the servo motor 101. When the voltage drops below 1.5 (V), the fourth differential amplifier 114 detects this and turns the servo motor 1 off.
Stop 01.

Therefore, the voltage of the movable contact 103 is 1.5 (V) or more.4.
If the voltage is 5 (V) or less, the output of the fourth differential amplifier 114 and the output of the fifth differential amplifier via the second inverter 120 are output.

FIG. 3 shows a circuit configuration diagram of the second embodiment. In the second embodiment, the configuration and operation of the position control section A are the same as those in the first embodiment described above, so a description thereof will be omitted. The operation limiting section B of the second embodiment is the fourth differential amplifier 11 of the first embodiment described above.
4 and a fifth differential amplifier 117, the + terminal of the fourth differential amplifier 114 and the position corresponding to the Max hot of the resistor 104 of the potentiometer 102 are connected,
One terminal of the fifth differential amplifier 117 and the potentiometer 12
The movable contact 103 of the potentiometer 102 is connected to one terminal of the fourth differential amplifier 114 and the position corresponding to Max cool of the resistor 104 of the potentiometer 102 .
It is connected to the child terminal of 7.

These operations are almost the same as in the first embodiment described above.

The movable contact 103 of the potentiometer 102
When the fifth differential amplifier reaches the cool position, the input voltage V at its one terminal and the input voltage V at the child terminal, that is, the movable contact 1
03, the voltage of the movable contact 103 is ■1
When the output becomes higher than that, the output is inverted from L to H. This is input to the second terminal of the servo motor drive circuit 112 and stops the servo motor 101. When the movable contact 103 of the potentiometer 102 reaches its Max hot position, the fourth differential amplifier 114 compares the input voltage 2 of its child terminal with the voltage of the movable contact 103, and
When the voltage of 03 becomes below 2, its output is inverted from L to H. This is input to the No. 1 terminal of the servo motor drive circuit 112 to stop the servo motor 101.

As is clear from the first and second embodiments described above, depending on the output of the potentiometer 102, the temperature control damper 2 is moved to the maximum heating position, which is one of the driving limits, or to the maximum cooling position, which is the other driving limit. The fourth differential amplifier 114 or the fifth differential amplifier 117 detects that the servo motor 1 has been driven to the position, and outputs the signal ``T''.
Stop 01. As a result, there is no need to provide a rotation limit switch consisting of a printed pattern and a slider that stops the servo motor 101 at the drive limit of the temperature control damper.
The servo motor 101 can be stopped at the drive limit of the temperature control damper. Therefore, the control device 1 can be downsized. Further, the autocoat roll potentiometer of the control device 1 can be provided in a space where a rotation limit switch is not provided. Also, at the drive limit, the servo motor 101
Since the current is not cut off at the contact, there is no risk of burnout of the contact, and the durability of the control device 1 can also be improved. Also, compared to the prior art in which the potentiometer and rotation limit switch are provided on the same printed circuit board, the potentiometer 10
The operating angle of 2 can be expanded, and the servo motor 101
It is also possible to expand the working angle of.

In the first and second embodiments described above, the position control section A is already a known part, and various circuit configurations and operations are possible. Further, although the first and second embodiments are servo motors that drive a temperature control damper of a vehicle air conditioner, each embodiment of the present invention is a servo motor that drives another damper of a vehicle air conditioner, It can be used for various servo motors.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a vehicle air conditioner, FIG. 2 is a circuit configuration diagram of a control device showing a first embodiment of the present invention, and FIG. 3 is a circuit diagram of a control device showing a second embodiment of the present invention. FIG. 3 is a circuit configuration diagram. DESCRIPTION OF SYMBOLS 1... Control device, 2... Temperature adjustment damper, 101.
...Servo motor, 102...Potentiometer, 1
05... Setting resistance, 112... Servo motor drive circuit. 114... Fourth differential amplifier, 117... Fifth differential amplifier, ~... Position control means, B... Operation restriction means. Figure 1

Claims (1)

[Claims] A potentiometer that works in conjunction with a servo motor, detects the operating position of the servo motor, and outputs it electrically; A servo motor control circuit comprising a position control means for controlling to an arbitrary target position within a range, the servo motor detecting from the output of the potentiometer that the servo motor has reached at least one stop position within the operating range. . A control circuit for a servo motor, comprising operation limiting means for outputting a stop signal for the servo motor to the position control means.