JPH0833416B2 - Meter drive controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an orthogonal magnetic field type meter drive control device in which two drive coils are combined orthogonally to each other.

2. Description of the Related Art In the case of an orthogonal magnetic field type meter, pointers are touched by mutually orthogonal magnetic fields generated by currents flowing in mutually orthogonal drive coils.

That is, as shown in FIG. 1, the coils Lx and Ly wound in a rectangular shape are combined so as to intersect with each other, and a ferrite magnet M is rotatably supported therein, and its pivot shaft Ma
Has one end penetrating the intersecting portion of both coils and a pointer P is fitted to the end.

Therefore, the magnetic field Hx generated in the coil Lx by the current Ix flowing in the coil Lx and the coil Ly by the current flowing in the coil Ly
As shown in FIG. 2, it is orthogonal to the magnetic field Hy generated at.

Then, the magnet M rotates and shakes the pointer P so that the N pole and the S pole of the magnet M are aligned in the direction of the synthetic magnetic field H formed by both magnetic fields Hx and Hy.

Now, when the same coil is used for both coils Lx and Ly, the ratio Iy / Ix of the current flowing through both coils is proportional to the ratio Hy / Hx of the magnetic fields Hx and Hy, and Hy / Hx is the combined magnetic field and the magnetic field Hx. Is equal to the tangent of the angle θ (the deflection angle of the pointer).

In this way, the pointer P can be drive-controlled by controlling the ratio of the currents Ix, Iy flowing through the coils Lx, Ly.

An example of a conventional meter using such an orthogonal magnetic field type meter driving means will be described with reference to the circuit diagram of FIG.

This example is applied to a speedometer, in which the signal from the speed pulser 01 is amplified by the amplifier 04 via the resistors 02 and 03, processed by the frequency divider 05 to a frequency with an appropriate ratio, and the F /
The V converter 06 converts the frequency into voltage.

This voltage is compared with the reference voltage by the comparator 07, and when it is larger than the reference voltage value, the transistor 08 is turned on and a current is passed through the coil Lx of the meter.

Although not shown, the comparator 07 and the transistor 08 are connected in parallel, and the reference voltage value of the comparator 07 is different,
The value of the current flowing through the coil Lx differs depending on the transistor 08 that is conducting.

Although not shown, the other drive coil Ly has a similar circuit, and a predetermined current is applied to the coils Lx, L according to the vehicle speed.
Moving the flow pointer to y.

Problems to be Solved by the Invention As described above, when the current flows through the drive coil in a nearly one-to-one correspondence with the detection signal and the pointer sways, the pointer sways violently in a range where the instruction fluctuation is large and it is difficult to read the instruction. .

Means and Actions for Solving Problems The present invention has been made in view of the above points, and an object of the present invention is to provide a meter provided with a drive unit of an orthogonal magnetic field type, particularly in a range in which the indication fluctuation of the meter is severe. The point is to suppress the deflection of the pointer of the meter to make it easier to read the instruction.

 The structure of the present invention will be described with reference to FIG.

In the meter provided with the orthogonal magnetic field type drive means A in which two drive coils are combined orthogonally to each other, B is
The detection signal is a measurement value determination means for further determining the measurement value.

According to the range of the measured value that the measured value judging means B has judged this time, C is calculated based on one or more new measured values, including the measured value of this time, in order to suppress the indicated fluctuation of the meter. It is a conversion means for converting the.

D is a storage unit that stores, as a table, a direction and a duty ratio of a current flowing through each drive coil as a control value corresponding to the measured value.

E is a search means for searching the table of the storage means D based on the measured value converted by the conversion means C and selecting a control value.

F is drive control means for driving the drive means A based on the control value selected by the search means E.

Since the conversion means C performs the calculation based on one or more new measured values including the current measured value to suppress the indicated fluctuation of the meter according to the range of the measured value, the converted value is converted.
For a range in which it is known in advance that the meter's indication fluctuation is severe, it is calculated based on the latest plurality of measured values and converted into a measurement location where the indication fluctuation is suppressed, and based on the converted measured value, the search means E stores the table of the storage means The control value, that is, the direction of the current flowing in the drive coil and the duty ratio are selected from the above, and the drive control means F drives the drive means A in accordance with the current direction and the duty ratio.

Therefore, in the range where the meter instruction fluctuation is severe, the deflection of the pointer of the meter is suppressed and the instruction is performed, so that it is possible to realize a meter in which the instruction is easy to read and easy to see.

Practical Examples The examples illustrated in FIG. 5 and subsequent figures will be described below.

 FIG. 5 is a circuit diagram of this embodiment.

The speed is detected by a speed pulser 1 which has a magnet attached to a portion of the transmission that rotates in proportion to the drive wheels of the transmission and which detects a magnetic field line rotating by a reed switch.

The pulse signal detected by the speed pulser 1 is amplified by the amplifier 4 via the resistors 2 and 3 and input to the microcomputer 5.

The microcomputer 5 uses the CPU 6 as a center to perform control processing using the RAM 8 as needed according to a program written in the ROM 7.

In the case of the present embodiment, it has a ROM 9 in which control values are stored as a table particularly corresponding to measured values.

The amplified detection pulse signal is input to the input interface 10 of the microcomputer 5 and processed, and the control value signal is output from the output interface 11 to the duty signal generators 12 and 13.

One duty signal generator 12 controls the current flowing in one coil Lx of the two drive coils, and the other duty signal generator 13 controls the current flowing in the other coil Ly. By processing the signal of the oscillator 14, a pulse signal having a duty ratio based on each control value is output to the base terminals of the transistors 17 and 18 via the amplifiers 15 and 16, respectively.

The emitters of the transistors 17 and 18 are grounded, and the collector terminals are connected to the coils Lx and Ly each having one end connected to the power supply.

ON / OFF based on the input pulse signals of transistors 17 and 18
The off operation controls the current value flowing in the coils Lv, Ly.

The positional relationship between the scale of the meter and the coils Lx, Ly of this embodiment is shown in FIG.

The direction of the magnetic field generated when a current is applied to the coil Lx in the positive direction is the x-axis positive direction, and the direction of the magnetic field generated when a current is applied to the coil Ly orthogonal to this is the y-axis positive direction. .

Then, the scale is marked with 0 Km / h in the negative direction of the x-axis, 180 Km / h in the positive direction of the x-axis and 90 Km / h in the positive direction of the y-axis, centered on the intersection of the x-axis and the y-axis, and equally divided between them. It is divided into and the scale is marked.

The table stored in ROM9 is shown in the table below.

Each control value for controlling the drive of the coils Lx, Ly corresponding to the measured vehicle speed (Km / h), that is, the duty ratio (%)
It is shown.

The measured value is the vehicle speed measured by measuring the number of pulses of the detection pulse signal every unit time, and the microcomputer 5 also judges this measured value.

When the vehicle speed is 90 Km / h or less, the current flowing in the coil Lx is
The direction of current flow is negative and the duty ratio is 100% constant, and the duty ratio of the current flowing through the coil Ly is changed to change the direction of the combined magnetic field.

Similarly, when the vehicle speed is 90 Km / h or more, the current flowing in the coil Lx is 100% with a duty ratio of 100% with the current flowing in the positive direction.
The direction of the synthetic magnetic field is changed by changing the duty ratio of the current flowing through the coil Ly while keeping it constant.

For example, when the vehicle speed is 30 Km / h, the coil Lx has a negative control value with a duty ratio of 100%, and the coil Ly has a duty ratio of 3%.
A control value in the positive direction of 3% is shown.

Based on such control values, the duty signal generator 12,1
3 generates a rectangular pulse signal having the duty ratio selected as described above as shown in FIG.

The ratio a / T to the period T of the time a at the high level of the signal is the duty ratio.

Therefore, when the vehicle speed is 30 Km / h, the duty signal generator
The signal generated by 12 has a continuous high level because it has a duty ratio of 100%, and the signal generated by the duty signal generator 13 has a duty ratio of 33%, so there is a cycle of high level It is a pulse signal corresponding to 33% of.

Such a signal is transmitted to the transistors 17, 18 via the amplifiers 15, 16.
Is operated, the transistors 17 and 18 are made conductive for the time when the pulse signal is at the high level, and the currents are made to flow through the coils Lx and Ly for the conductive time.

Therefore, the average value of the current flowing through the coils Lx and Ly corresponds to the respective duty ratios, and the magnetic fields Hx and Hy are formed in proportion to this average current value, and the direction of the pointer is determined by the combined magnetic field of these. .

In this embodiment, the display method adapted to the required specifications of the speedometer in each country is adopted. Therefore, the microcomputer 5 processes the input measured value after determining the measured value, Based on this, select the control value.

Processing of measured values can be easily done by program operation. The required specifications of the speedometer differ from country to country, and there are countries that have a tolerance range that is smaller than the actual speed and countries that have a tolerance range that is higher than the actual speed, but control is performed by multiplying the measured value by a certain coefficient. The value can be changed slightly, and the indication of the pointer can be displayed correspondingly to a smaller or larger number than the actual value within the allowable range.

In this embodiment, the vehicle speed is determined by the CPU 6 and the control value (duty ratio) is measured based on the measured value obtained by processing the same vehicle speed, so that the accuracy is high and the finger pointing performance can be obtained without adjustment.

The drive control circuit is simplified because the processing from detection value input to control value selection is performed by a single microcomputer.

Next, as an example of adopting another display method, an example of enlarging and displaying the designated band most desired to be used will be shown.

 In this example, the apparent resolution can be increased.

That is, the instruction band that is often used without making the scale intervals equal is to enlarge the scale intervals.

For example, in the case of a speedometer, it is not necessary to accurately recognize the speed between 0Km / h and 20km / h, so the scale intervals may be narrow, and between 20Km / h and 100Km / h, the vehicle speed can be accurately recognized. It is necessary to keep it in advance, so make sure to enlarge the scale interval when instructing.

In such a case, it can be easily dealt with by changing the coefficient by which the measured value is multiplied at a vehicle speed of 20 km / h.

It is also possible to gradually increase the scale interval by making the coefficient a variable proportional to the vehicle speed.

In this embodiment, unnecessary fluctuations in the measured value are not displayed as they are, and the fluctuation of the pointer is suppressed for easy viewing.

For example, there is a fluctuation in the engine speed during idling in a meter that displays the engine speed, but this does not necessarily have to be displayed accurately, and if it is displayed correctly, the wobbling of the pointer becomes rather difficult to see.

This is a circumstance that particularly occurs at a rotation speed of 1000 rpm or less, so the measured value is processed and provided for display based on the flowchart shown in FIG.
It is possible to instruct the following rotational speeds while suppressing variations.

That is, in FIG. 8, the number of revolutions N is first determined (step), and then the content of B (engine number of revolutions) previously displayed is entered in A (step).

Then, the rotation speed N determined in step is entered in B (step), and it is determined whether the content of B is less than 1000 rpm (step).

If it is less than 1000 rpm, proceed to the step and change the contents of B.

That is, one-third of the variation (BA) is added to A, which is the content of the vehicle speed displayed previously, to be the content of B (step).

Then, the contents of B are displayed (step) and the process returns to the step.

If the content of B is 1000 rpm or more in the step, it skips the step and advances to the step.
That is, the number of revolutions N newly determined is displayed as it is (step), and the process returns to the step.

For example, if the previously displayed rotation speed is 750 rpm and the newly determined rotation speed is 810 rpm, A = 750, B = 810
Since B <1000, the process proceeds from step to step, calculation is performed and B = 770, and 770 rpm is displayed.

In this way, even if the number of revolutions is actually increased from 750 rpm to 810 rpm, the fluctuation is suppressed and 770 rpm is displayed, so that the deflection of the pointer is reduced to make it easier to read and the approximate number of revolutions can be recognized.

It should be noted that, regarding the rotation speed of 1000 rpm or more, the fluctuation is not so severe, it is not difficult to see the measured value as it is, and it is necessary to display it accurately, so the new measured value is displayed as it is.

As described above, since the measurement value can be easily processed by software, the movement of the pointer can be freely designed, and it is possible to easily provide the most visible meter.

Moreover, although the example applied to the speedometer and the tachometer is shown, it can be applied to various meters such as a fuel gauge and a water temperature gauge.

EFFECTS OF THE INVENTION The present invention provides a conversion means for performing conversion on the basis of one or more new measured values including the present measured value and the measured value so as to suppress the indication fluctuation of the meter according to the range of the measured value. Since it is equipped with, the range in which the indication fluctuation of the meter is known to be severe in advance is calculated based on the latest multiple measurement values and converted into a value that suppresses the indication fluctuation, and driven based on the converted measurement value. By controlling, it is possible to realize a meter that is easy to read and that is easy to read instructions while suppressing the shaking of the pointer.

[Brief description of drawings]

FIG. 1 is a perspective view of an orthogonal magnetic field type meter drive device, FIG. 2 is an explanatory view showing the direction of a magnetic field, FIG. 3 is a view showing a conventional meter drive control circuit, and FIG. 4 is a configuration of the present invention. 5 is a circuit diagram of a meter drive control device according to an embodiment of the present invention, FIG. 6 is an explanatory view showing a relationship between a meter scale and a magnetic field of the embodiment, and FIG. FIG. 8 is a diagram showing an output pulse signal of the duty signal generator of the same embodiment, and FIG. 8 is a flowchart showing processing of measured values in another embodiment. 1 ... Speed pulser, 2,3 ... Resistance, 4 ... Amplifier,
5 ... Microcomputer, 6 ... CPU, 7 ... RO
M, 8 ... RAM, 9 ... ROM, 10 ... input interface, 11 ... output interface, 12,13 ... duty signal generator, 14 ... oscillator, 15,16 ... amplifier, 17,18
...... Transistor 18, Lx, Ly …… Coil.

Claims (1)

[Claims] 1. A meter provided with an orthogonal magnetic field type driving means in which two driving coils are combined orthogonally to each other, and a measured value judging means for judging a measured value from a detection signal, and the measured value judging means. Conversion means for performing calculation on the basis of one or more new measured values including the measured value to convert the measured value according to the range of the measured value determined this time, in order to suppress indication fluctuation of the meter; Storage means for storing, as a table, the direction and duty ratio of the current flowing in each drive coil as a control value corresponding to the value, and searching and controlling the table of the storage means based on the measurement value converted by the conversion means. A drive control device for a meter, comprising: a search means for selecting a value; and a drive control means for driving the drive means based on the control value selected by the search means.