JPS6033366Y2 - Vehicle direction meter - Google Patents

Description

[Detailed description of the invention] The present invention relates to a direction meter that displays the direction in which a vehicle is traveling based on the direction signal of a direction detection sensor, and particularly indicates that the direction display is inaccurate in places where the earth's magnetic field is disturbed. It is something.

Conventionally, with a device that detects the direction in which a vehicle is traveling based on the earth's magnetism, it is impossible to determine the correct direction in a place where the earth's magnetism is greatly disturbed.

Therefore, in places where the geomagnetic field is significantly disturbed, it is necessary to detect this disturbance and display a message to notify the user that the direction display is not accurate.

The present invention was developed in view of the above, and includes a direction detection sensor that detects the direction of travel of the vehicle using the influence of earth's magnetic field, and a direction detection sensor that is installed inside the vehicle and detects the direction of travel of the vehicle based on the direction signal from the direction detection sensor. and an abnormality detection circuit that generates an abnormality signal when it detects that the direction signal from the direction detection sensor exceeds a predetermined level region due to the geomagnetic abnormality. and an abnormality display drive circuit that causes the display unit to display an abnormality based on the abnormality signal from the abnormality detection circuit, it is possible to display the traveling direction of the vehicle by taking into consideration whether the earth's magnetic field is normal or abnormal. The purpose of this invention is to provide a direction meter for a vehicle.

The present invention will be explained below with reference to embodiments shown in the drawings.

Fig. 1 shows the configuration of the first embodiment of the vehicle azimuth meter according to the present invention, in which numeral 1 denotes a azimuth detection sensor, with excitation windings ID on a magnetic core IC made of ferromagnetic material, and an excitation winding ID arranged orthogonally to each other. Output windings IA and IB are wound respectively.

2 is an oscillation circuit which outputs a rectangular wave signal A (FIG. 2 1) to excite the excitation winding ID at a frequency f.

The magnetic field within the magnetic core IC changes according to the strength H of the horizontal component of the earth's magnetism, and outputs proportional to this are output from the output windings IA and IA, respectively.
Output X at a frequency of 2f by filters 3A and 3B of the same configuration taken out from the IB and protected from capacitors and resistors,
Y (Fig. 2, 2 and 3) is obtained.

Since the outputs X and Y change depending on the direction of the direction detection sensor 1, that is, the direction in which the vehicle is traveling, the outputs X and Y are sent to the amplifier circuit 5A.

5B to adjust each maximum value to be equal.

Here, if the maximum values are equal in advance, the amplifier circuits 5A and 5
B becomes unnecessary.

When the direction detection sensor 1 is rotated 360 degrees in a parallel magnetic field, the locus of the output X and Y values at the timing of the signal B from the timing circuit 4 (Figure 2, 4) will follow the geomagnetic field as shown in Figure 3. The radius KH (V
OLT), is a constant) circle.

Now, considering the case of digital display of 8 directions (N=2) out of 4N directions, since the l direction is 45 degrees, the predetermined comparison voltage v1. V2 is V1=KHsin22.5°#0.3827KH(V
OLT) V1 = -KHsin22.5° -0,38
27KH (VOLT), and the signals obtained by amplifying the signals from the output windings IA and IB are each divided into three signal levels.

When the geomagnetism decreases due to external influences, the trajectory of the output X and Y values becomes small, and when the geomagnetism increases due to external influences, the trajectory of the output X and Y values increases.

Comparison voltage V1. Since V2 is determined and constant for each region, if the earth's magnetic field is greatly disturbed in this way, there is a possibility that the display of the vehicle's heading will deviate greatly from the true heading.

A predetermined comparison voltage V1. V2, and a predetermined comparison voltage V) It VL is used to determine whether the earth's magnetism has become too strong.

Comparison voltage V, , VL is VH = 1.5KH (VOLT) VL=-1,5KH (VOLT) Set to .

The comparators (MC3302P manufactured by Motorola) 6A, 6B, 6C, and 6D in Figure 1 compare the output , the result @ a, 6 bg 6 Ct 6
The relationship between the comparator outputs of dg 6 eg 6f, 6g, and 6h and the traveling direction of the vehicle is uniquely expressed as shown in the following table.

For example, 6at6b are both at 440H level, and 6e is “
If 1゛ level and 6f are “0゛ level, the direction is 'Nu.
(north), and 6a is “1°” and level 6b is “0”
If level 6e is "1" level and 6f is "0" level, the direction is rNEJ (northeast).

The outputs of comparators 6A, 6B, 6E, and 6F are connected to a decoder 7 with a latch (TC4514BP manufactured by Tokyo Shibaura Electric Co., Ltd.), and when the outputs X and Y are in the normal range (outside the range of NCI and NC2), the timing circuit Signal B from 4
The outputs of the comparators 6A, 6B, 6E, and 6F are latched at the timing of , and the logic of the decoded output is taken by the logic circuit 9, so that the heading display section 10 digitally displays the heading of the vehicle.

If the geomagnetism is too small, that is, the outputs X and Y are Nc
When the outputs X and Y are in the NC2 region and the earth's magnetic field is too large, the abnormality detection circuit 8 outputs the OR gate 82, NOR gate 81, and NAN.
The D gate 83 takes the logic, and the D flip-flop 84
The abnormality detection state is stored in .

The output signal of this D flip-flop 84 is inverted from a "0" level signal during normal operation to a "1" level signal when an abnormality is detected.

In the abnormality display circuit 11, the transistor 112 constituting the abnormality display drive circuit is turned on by the "1" level signal, and the light emitting diode 111 is turned on by receiving power from the 8V power supply terminal.

The light emitting diode 111 constitutes a display part (shown in FIG. 7A) together with the direction display part 10 and is installed in the vehicle interior, and the light emitting diode 111 lights up to inform the occupants of the vehicle of abnormalities in the earth's magnetic field.

In the above embodiment, the detailed circuit configurations of the oscillation circuit 2 and the timing circuit 4 are shown in FIG.

In FIG. 4, 2a in the oscillation circuit 2 is a ring oscillator, and 2b is a counter (TC4520B manufactured by Tokyo Shibaura Electric Co., Ltd.).
4a in the timing circuit 4 is a counter decoder (TC4017BP manufactured by Tokyo Shibaura Electric Co., Ltd.).

Further, a detailed circuit configuration of the logic circuit 9 and the direction display section 10 is shown in FIG.

In FIG. 5, 9a in the logic circuit 9 is an encoder (TC4532BP manufactured by Tokyo Shibaura Electric Co., Ltd.), and 9b is a decoder (TC4051BP manufactured by Tokyo Shibaura Electric Co., Ltd.).

The above components 1 to 9a are provided on the ceiling of the vehicle, and the components 9b to 11 are provided on the instrument panel, and the three signal lines are connected using signal conversion by the encoder 9a and decoder 9b. I have to.

The case of digital display in 8 directions has been described above, but in the case of digital display in small directions (N = 1.2...), the voltage level with the lowest absolute value among N predetermined voltage levels. By comparing the outputs of the amplifier circuits 5A and 5B and also at a predetermined voltage level VH9VL, the light emitting diode 111 is turned on to notify the occupants of the vehicle that the display of the vehicle's heading in response to an abnormality in the earth's magnetic field is inaccurate. is clear.

Although the oscillation circuit 2 excites the excitation winding ID with the rectangular wave signal A of frequency f, a sine wave signal may also be used.

Note that a fluorescent display tube, a lamp, an LED, a liquid crystal, etc. are used as the digital display of the direction display section 10, and symbol display is also possible.

FIG. 6 shows the constituent countries of the second embodiment of the vehicle direction meter according to the present invention, in which the first embodiment displays a digital direction of travel, while the second embodiment displays an analog direction of travel. Components that are the same as those of the first embodiment are given the same reference numerals.

IIA and IIB are hold circuits and output X. Y is held at the timing of signal B from timing circuit 4.

12 is an analog direction display section with hold circuits 11A, I
In response to the output from the IB, the vehicle's heading is displayed in an analog manner using a pointer.

When the earth's magnetism is greatly disturbed (as shown in the seventh diagram), it is detected and stored in the abnormality detection circuit 8, and the light emitting diode 111 of the abnormality display circuit 11 is turned on, as in the case of the first embodiment.

In addition, in the first and second embodiments described above, when an abnormality in the earth's magnetic field is detected and stored in the abnormality detection circuit 8, the light emitting diode 111 of the abnormality display circuit 11 is turned on, but other indicators are turned on or Blinking may also be used, and in the first embodiment, an abnormality display method such as blinking, turning off, dimming brightness, or discoloration of the indicated direction in the direction display of the direction display unit 10, or lighting or blinking of the omnidirectional display An abnormality display method may be used such as turning off the light, dimming the brightness, or changing color. Furthermore, in the second embodiment, an abnormality display method such as rotating the pointer of the analog direction display section 12 may be used.

Next, examples of various abnormality displays by the display section 10.12 and the light emitting diode 111 are shown in FIGS. 7A, B, and C.

Explanation will be given according to D and E.

In this FIG. 7, 'A, B, and C show examples of abnormality display by the digital orientation display unit 10 and the light emitting diode 111, and 'D' shows examples of abnormality display by the digital orientation display section 10 and light emitting diode 111.

E is an analog direction display section 12 and a light emitting diode 111
An example of an abnormality display is shown below.

First, in FIGS. 7A and 7B, numerals 10a to 10h are display pieces representing eight directions of travel, and are lit only in the direction of travel, and 111 is the light emitting diode shown in FIG.

In Fig. 7C, 10 to 10n is a symbol display section that displays the direction of travel, and for example, if it is in the NE force direction, 10 and 101
are lit at the same time and the others are off, and in the S direction, only the master is lit and the others are off, and when an abnormality is detected, the light emitting diode 111 is lit.

In Fig. 7E, 12a is a display pointer, and 12b is a panel.The pointer 12a moves according to the direction of travel to indicate the direction of travel, and the light emitting diode 111 performs the same operation as in the previous example.

As described above, in the present invention, the traveling direction of the vehicle is displayed based on the direction signal from the direction detection sensor that detects the direction of travel of the vehicle using the influence of the earth's magnetic field, and the direction signal is detected due to an abnormality in the earth's magnetic field. When the abnormality detection circuit detects that the level has been exceeded, the abnormality display drive circuit displays the abnormality on the display section, so information on whether the geomagnetism is normal or abnormal can be provided at the same time depending on the display state of the display section. Therefore, it is possible to prevent misjudgment of the direction of travel due to the display on the display when there is an abnormality in the geomagnetic field.Furthermore, by displaying the abnormality in the earth's magnetic field, the occupants of this vehicle can be informed of appropriate visual guidance without calling for extra attention. This has the excellent effect of being able to report abnormalities in the geomagnetic field at any given time.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing the first embodiment of the present invention, Fig. 2 1.2.3.4 is a signal waveform diagram for explaining the operation of the present invention, and Fig. 3 is for explaining the operation of the present invention. 4 is an electrical wiring diagram showing the detailed configuration of the oscillation circuit and timing circuit in FIG. 1; FIG. 5 is an electrical wiring diagram showing the detailed configuration of the logic circuit and direction display section in FIG. 1; Fig. 6 is an overall configuration diagram showing the second embodiment of the present invention, Fig. 7 A, B, C, D,
E is a partial configuration diagram showing various orientation display examples. 1...Direction detection sensor, IA, IB...
・Output winding, IC...magnetic core, 1D...
Excitation winding, 2...Oscillation circuit, 4...Timing circuit, 6A, 6B, 6C, 6D, 6E, 6F,
6G, 6H...Comparator, 7...
Decoder with latch, death...abnormality detection circuit, 112
. . . Transistor constituting the abnormal display drive circuit, 10, 111 . . . Direction display section, light emitting diode constituting the display section.

Claims (1)

[Scope of Claim for Utility Model Registration] A direction detection sensor that detects the direction of travel of a vehicle using the influence of earth's magnetic field; , a display section having a function of displaying the geomagnetic anomaly; an anomaly detection circuit that generates an anomaly signal when it detects that the azimuth signal from the azimuth sensor exceeds a predetermined level area due to the geomagnetic anomaly; A compass for a vehicle, comprising: an abnormality display drive circuit that displays an abnormality on the display section based on an abnormality signal from an abnormality detection circuit.