JPH0238924A - Motor control circuit for meter - Google Patents

Abstract

PURPOSE:To fully utilize a torque produced in a motor and to simplify a control circuit by making the motor operation to an ON/OFF operation. CONSTITUTION:A pulse signal obtained by a sensor 400 for the detection is inputted to a comparator circuit 500 and a reversal comparator circuit 600 through a voltage conversion circuit 800. A signal to indicate the display position is detected n the motor 200 or a display mechanism 300, and this signal is taken out by a voltage conversion circuit 900 as outputs in two systems which are provided with a small potential difference, then inputted to the comparator circuit 500 and the reversal comparator circuit 600. The motor 200 is made to rotate forward/backward and to stop by means of inputting the outputs of the comparator circuit 500 and the reversal comparator circuit 600 to a bridge driving circuit 700 for the motor, and a specified display is made on a meter panel 110 through a display mechanism 100.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a driving device for an instrument used in a vehicle instrument, etc., and particularly relates to a drive device for an instrument used in a vehicle instrument, etc. The objective is to improve the technology for displaying information on the instrument panel surface.

(Prior art) Among vehicle instruments, the ones that move the indicated value linearly according to the movement of the motor are generally rotary type, eddy current type, moving coil type, and crossed coil type meters. There is insufficient torque.

Therefore, conventionally, for example, as a linear display speedometer, as shown in FIG. 4, it is common to operate a motor control circuit 9 to control the motor 2 using signals from a speed detection sensor 4 and a position detection sensor 3. It is being carried out according to

In the figure, 1 is a belt-driven display mechanism connected to the motor 2, and 10 is a pointer 1a provided on the display aami.
This is a speed display board with an indicator indicating the speed.

As an example of the motor control circuit 9, for example, the fifth
There is a linear servo system shown in the figure.

In this method, a pulse signal obtained by the sensor 4 is converted into a voltage signal that changes linearly by a voltage conversion circuit 7, and is input to one input terminal of a DC differential amplifier 5. On the other hand, the position detection sensor 3 is, for example, a potentiometer that directly detects the rotational phase of the motor 2 or detects the phase according to the movement of the display mechanism 1. It is input to the other side input terminal of the differential amplifier 5.

Then, the differential amplifier 5 has an output state corresponding to the difference between the two human forces, and outputs the output from this to the motor 2 through the linear bridge driver circuit 6, thereby driving the motor 2 to rotate.

The motor 2 performs normal rotation, reverse rotation, and stop depending on the input difference, and displays a predetermined speed on the instrument panel 10 through the display mechanism 1.

Further, as an alternative to such a linear servo method, there is a digital servo method.

In this system, as shown in FIG. 6, a pulse signal obtained by a speed sensor 4 is processed by a conversion circuit 11, and inputted to a command circuit 12 composed of a CPU or the like.
Through the signal processing, a position command signal is input to one input terminal of the digital motor control circuit 13.

On the other hand, a signal indicating the display position is sent to the motor 2 or the display mechanism 1.
The output is taken out from the position detection sensor 3 consisting of a digital potentiometer or the like via the digital potentiometer, and the output is inputted to the other side input terminal of the digital motor control circuit 13.

Based on these two signals, the control circuit 13 outputs a rotation control signal to the motor 2 according to the position command signal of the command circuit 12, and the corresponding rotation of the motor 2 causes a predetermined speed to be displayed on the instrument panel 10 via the display mechanism 1. Perform display.

(Problem to be Solved by the Invention) However, the former linear servo system has the disadvantage that when the input voltage from the speed sensor and the feedback voltage from the position detection sensor become close, the differential output becomes small, resulting in a lack of motor torque. there were.

Therefore, it was necessary to increase the torque of the motor or increase the gain of the differential amplifier.

Mana, in the latter digital servo method, Digital IIJ
Although this improved detection accuracy, the position detection sensor and control circuit required too much cost, which was economically disadvantageous.

This invention was made to solve the above problems, and by turning the motor ON and OFF, the torque generated by the motor can be fully utilized, the control circuit is simplified, and the cost is reduced. The purpose of the present invention is to provide a motor control circuit for an instrument that can be manufactured at low cost.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention includes a detection sensor, a position detection sensor that detects the rotational position of the motor,
A voltage conversion circuit that inputs the signal from the position detection sensor and outputs two signals with a slight potential difference, and a signal from the detection sensor and each signal from the voltage conversion circuit are connected to the input terminal. The motor bridge drive circuit includes a comparison circuit, an inversion comparison circuit, and a motor bridge drive circuit that receives outputs from these comparison circuits and inversion comparison circuits, and rotates the motor in the forward or reverse direction or stops the motor according to the output states of both.

(Function) As shown in FIG. 1, the pulse signal obtained by the detection sensor 400 is changed into a voltage signal that changes linearly by the voltage conversion circuit, and this signal is sent to one of the comparison circuit 500 and the inversion comparison circuit 600. Input at the input end. On the other hand, the signal indicating the display position is transmitted directly or indirectly to the position detection sensor 3 via the motor 200 or the display mechanism 100.
00, and this signal is taken out as two outputs with a slight potential difference by the voltage conversion port 11900 and input to the other input terminals of the comparison circuit 500 and the inverting comparison circuit 600. By inputting the outputs from these to the motor bridge driver circuit 700, the motor 200 rotates forward and reverse.

The engine is stopped and a predetermined display is displayed on the instrument panel 110 via the display mechanism 100.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

In FIG. 2, this motor control circuit includes a speed detection sensor 400, an F/V conversion circuit 800 that inputs a pulse signal from the speed detection sensor and converts it into a voltage change, and a display mechanism 100. A potentiometer 300 that detects the position, and this potentiometer 30
a voltage conversion circuit 900 that receives a signal from 0 and outputs two systems of signals with a slight potential difference; a comparison circuit 500 that receives outputs from the F/V conversion circuit 800 and the voltage conversion circuit 900; and an inversion comparison circuit. The motor bridge drive circuit 700 receives outputs from the comparator circuit 500 and the inverting comparator 1N1600, and rotates the motor in the forward or reverse direction or stops the motor in accordance with the output states of both.

The display mechanism 100 includes a rotor 102 rotatably connected at one end to a motor 200 via a reduction gear group 101, a pin 104 that slides into a spiral cam lead groove formed in the rotor 102, and a slider shaft. It consists of a slider 103 that slides along the slider 105, and a pointer 106 that slides together with the slider 103 and indicates an index formed on the instrument panel 110.

The other end of the rotor 102 is connected to the input shaft of the potentiometer 300 via a reduction gear group 107, and is rotated, thereby changing the resistance RP. One end (■) of the resistor RP is connected to the power supply Vcc, the other end (■) is connected to the ground side via a resistor RE provided inside the voltage conversion circuit 900, and the contact (■) is also connected to the voltage conversion circuit 90.
0 resistors RA and RC.

The voltage conversion circuit 900 includes resistors RA-RB.

The comparator circuit 50 is composed of two series of RC-RD DC circuits, and the voltages of the two series with a slight potential difference created by voltage division are applied to the comparator circuit 50.
0 and a feedback input to the inversion comparison circuit 600.

That is, the DC circuit has the following relationship.

However, RP +RE (<RA +RB, RC+RD
This is necessary to obtain linear feedback input.

Note that the same effect applies even if the above is reversed, and in this case, the motor 200 simply rotates in the opposite direction.

The comparison circuit 500 and the inversion comparison circuit 600 are both comparison circuits A made up of comparator ICs.

The inverting comparator 600 inverts the input by connecting the converter C to the output terminal of the comparator circuit B.

Moreover, when the signal of the speed detection sensor 400 is “0”,
In other words, even when the speed is "0", the voltage E between It is set so that it does not become 0.

Similarly, the output of the F/V conversion circuit 800 also has a speed of “0”.
/) The voltage must not be "0", and of course the F/V conversion circuit 800 from the speed "0" to the maximum speed
and the voltage change of the voltage conversion circuit 900 are both in the same state.

Next, the principle of forward rotation, reverse rotation, and stopping of the motor by the bridge driver circuit 700 will be explained.

First, the operation of the motor with respect to the input/output to the bridge driver circuit 700 is as shown in Table 1 below.

In order to establish the potential difference shown in Table 1 (main brake and stop), the input to the bridge driver circuit 700 must be F/A.
When there is a difference between the voltages of the output EF of the V conversion circuit 800 and the outputs Ea (input voltage to the comparison circuit A side) and Eb (input voltage to the comparison circuit B side) of the voltage conversion circuit 900, H, A converter C is provided in the comparator circuit B so that the signal becomes L, H, or H.

Since there is a slight potential difference between the output voltages Ea and Eb, the output voltage characteristics will be as shown in the graph of Figure 3, and only one comparison circuit will be inverted, so the motor will stop.
The display mechanism is also stopped. Here, when either voltage changes again, the motor 200 rotates forward or reverse. Note that converter C may be included in either of comparison circuits A and B. In the opposite case to the embodiment, motor 2
00 is simply rotated in the opposite direction.

Table 2 below collectively displays the output of the bridge driver circuit 700 for each input voltage to the comparison circuits A and B, and the motor operation and pointer movement based on the output.

Table 2 In addition, although the display in the embodiment has been described as an ellipse in which the pointer is displayed by linear movement, this invention is not limited to this, and depending on the am itself, it may be displayed in a rotating manner. is possible.

[Effects of the Invention] As explained in detail in the embodiments above, the motor only repeats ON and OFF operations of rotation in the forward and reverse directions.
Compared to conventional differential output, there is no torque shortage that occurs when the differential output is small, and the full torque can be generated.
can be made more compact.

Further, according to the present invention, the motor control circuit itself can be simplified and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a motor control circuit according to the present invention, and FIG. 2 is an explanatory diagram showing its specific circuit configuration.
Figure 3 is a graph showing the same output characteristics, Figure 4 is a schematic explanatory diagram showing the general configuration of a linear type meter, and Figure 5 is a block diagram showing the electrical configuration of a conventional linear servo type motor control circuit. 6 are block diagrams showing the electrical configuration of a conventional digital servo type motor control circuit. 00...Display mechanism OO...Motor 00...Position detection sensor 00...Comparison circuit 00...Inversion comparison circuit 00...Motor bridge driver circuit OO...Voltage conversion circuit Agent Patent attorney Yasuo Miyoshi

Claims (1)

[Claims] (1) A detection sensor, a position detection sensor that detects the rotational position of the motor, a voltage conversion circuit that inputs signals from the position detection sensor and outputs two systems of signals with a slight potential difference, and a detection sensor. A comparator circuit and an inverting comparator circuit whose input terminals are connected to the signal from the sensor and the signal from the voltage converter circuit, respectively, and the outputs from the comparator circuit and the inverting comparator circuit are connected to each other. A motor control circuit for an instrument, comprising a motor bridge drive circuit that rotates the motor in forward and reverse directions and stops the motor.