JPS6239361B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an azimuth detecting device that measures azimuth by electrically detecting the direction of earth's magnetic field.

2. Description of the Related Art Conventionally, a magnetic headlamp and a wheel headlamp are known as devices for detecting azimuth. The former type of magnetic compass uses a rotatable magnetic needle to measure direction by having its magnetic pole point to the earth's magnetic pole. However, because of the structure of this type of device, which holds the magnetic needle in a manner that produces as little frictional resistance as possible, it is difficult to accurately measure the orientation in such an environment where the pointer sways due to vibrations, shocks, etc. Furthermore, obtaining an electrical signal from the indicated direction of the magnetic needle requires a complicated interface, which poses a practical problem.

On the other hand, the latter type of wheeled compass takes advantage of the property of a gyroscope to point in a fixed direction in space, and uses an appropriate method to apply a moment of gravity, thereby moving the axis of rotation in a fixed direction on the earth, such as north. It was designed so that it faced However, such devices generally have a complicated structure and are expensive, making them unsuitable for relatively simple uses.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a direction detection device that is small in size, inexpensive, and particularly less susceptible to the effects of vibrations, shocks, and the like. Hereinafter, one embodiment of the present invention will be described in detail with reference to the rotating section shown in FIG. 1, the block diagram shown in FIG. 2, and the circuit diagram shown in FIG. 3. FIG. 1 is a perspective view showing the rotating part. In the figure, 1 is a rotating shaft that is rotationally driven by a motor (not shown) and held approximately vertically, and 2 is an iron core 2A attached horizontally to the tip of the rotating shaft 1. This is a detection transformer around which a coil 2B is wound. Reference numeral 3 denotes a slip ring which is provided on the rotating shaft 1 and guides the winding end of the coil 2B to the outside. Reference numeral 4 denotes a light-emitting indicator, such as a light-emitting diode, provided on an arm extending from the rotating shaft 1, and the terminal of the light-emitting diode 4 is also connected to the slip ring 5. The rotation of the rotating shaft 1 causes the coil 2B of the detection transformer 2 to cut the lines of magnetic force of the earth's magnetism, thereby leading the signal induced in the coil 2B to the outside via the brush 6 that is in sliding contact with the slip ring 3. In this case, the induced voltage in the coil 2B becomes a sine wave with a maximum value when the coil 2B passes through the lines of magnetic force at right angles, and a minimum value when the coil 2B passes in parallel.

As shown in the block diagram of FIG. 2, a sine wave signal taken out through a slip ring 3 and a brush 6 is amplified by a preamplifier 7, and a zero level is detected by a zero detector 8. The zero detector 8 determines the zero level of the signal as well as the direction of change thereof, and outputs a pulse signal if it detects the zero level when the signal changes from negative polarity to positive polarity, for example. And 9
is a monomultivibrator that outputs a pulse signal of a predetermined width in response to the output pulse of the zero detector 8, and this output pulse is applied to the light emitting diode 4 via the brush 10 and the slip ring 5 as a drive signal for the light emitting diode 4. I'm trying to turn it on.

With such a configuration, by rotationally driving the rotating shaft 1, a sine wave signal as shown in FIG. 3a is induced in the detection transformer 2, and the slip ring 3,
It is applied via a brush 6 to a preamplifier 7. Then, when the output of this preamplifier 7 is given to the zero detector 8, the third
A pulse signal as shown in Figure b is obtained. Then, this pulse signal is converted into a pulse signal of a predetermined pulse width as shown in FIG. 3c by the mono-multivibrator 9, and is applied to the light emitting diode 4 to light it up.
As is clear from the time chart shown in FIG. 3, the light emitting diode 4 lights up at only one point at the zero-cross point of the output signal of the detection transformer 2, that is, during one rotation of the rotating shaft 1. Therefore, the observer can visually see that the light emitting diode lights up in a certain direction with respect to the rotation axis 1, and can thereby know the direction, for example, the north of the magnetic pole.

Here, the induced voltage V _o of the coil rotating in the magnetism
is given by the following equation 1).

V _o = jωban cosθ×10 ^-8 where j is an imaginary number sign ω is the angular velocity of the coil b is the magnetic flux density a is the cross-sectional area of the coil n is the number of turns of the coil θ is the angle between the coil and the magnetic flux where the cross-sectional area is 1 cm ² , If a coil with 1000 turns is rotated 100 times per minute and placed in a 0.3 Gauss magnetic field near Japan, the maximum value of the induced voltage V _nax will be as follows 2)
It is given by Eq.

V _nax = 100 x 2π x 0.3 x 1 x 1000 x 10 ^-8 = 1.884 x 10 ^-3 V = 1.884 mV...(2) Also, by winding the coil around the iron core, the induced voltage V _o can be reduced to several tens of The signal is amplified twice and an output voltage of several tens of mV is obtained, making it possible to obtain a signal level sufficient for practical use.

FIG. 4 is a specific circuit diagram of the above embodiment, in which operational amplifiers OP1, OP2, and OP3 constitute a preamplifier 7, a zero detector 8, and a monomultivibrator 9, respectively.

Note that the present invention is not limited to the above-mentioned embodiment, and for example, as shown in the block diagram shown in FIG.
1 may be inserted, and the phase amount in this phase shifter 11 may be set externally by the variable phase switch 12. In this way, the light emitting diode 4 can be turned on in a desired direction according to the phase amount instructed by the phase variable switch 12 to display that direction.

Therefore, the orientation can be measured with a simple structure, and is particularly resistant to vibrations, shocks, etc., and the electric signal can be easily extracted by leading out the driving signal of the light emitting display to the outside.

As described in detail above, the present invention detects the zero level of the output signal of a rotationally driven detection transformer with a zero detector, and uses this detection signal to drive a light emitting display that rotates together with the detection transformer to emit light. It was designed so that Therefore, it is possible to provide an azimuth detection device that can measure azimuth with a simple configuration, is less susceptible to vibrations, shocks, etc., and can obtain an electrical signal indicating the detected azimuth.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a rotating part of an embodiment of the present invention, Fig. 2 is a block diagram of the above embodiment, Fig. 3 is a time chart explaining the operation of the above embodiment, and Fig. 4 is a diagram showing the above embodiment. Example Circuit Diagram FIG. 5 is a block diagram of another embodiment of the invention. 1... Rotating shaft, 2... Detection transformer, 5... Light emitting diode, 7... Amplifier, 8... Zero detector, 9... Mono multivibrator.

Claims (1)

[Claims] 1. A detection transformer installed in a rotationally driven rotating part, an amplifier that amplifies the induced voltage generated when the detection transformer passes through the earth's magnetic flux, and a zero detection device that detects the zero level of the output signal of this amplifier. and a light emitting indicator provided on the rotating section and driven by the output of the zero detector.