JPH0125430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a geomagnetic sensor in a compass that is mounted on a vehicle and detects the geomagnetism and displays the relative relationship (for example, angle) between the direction of the horizontal component and the direction of travel of the vehicle. Concerning disturbance prevention methods.

In general, automobiles are equipped with various electrical components such as a generator and an electromagnetic clutch for the compressor for the air conditioner in the engine room, and the rear window is equipped with anti-fog hot wires. However, there is a problem in that a magnetic field is generated during operation, which adversely affects the geomagnetic sensor and disturbs the compass. At that time, regardless of the installation position of the geomagnetic sensor, the magnetic flux generated from various electrical components will necessarily affect the geomagnetic sensor installed at a location far from the source of the magnetic flux as it travels through magnetic materials such as the engine and car body. It has become something that affects people.

The present invention has been made in consideration of these points, and provides a method for preventing disturbance of a geomagnetic sensor, which prevents the geomagnetic sensor from receiving disturbance due to magnetic fields generated during the operation of various electrical components.

Now, if a geomagnetic sensor is installed on the hood of the engine room and the electromagnetic clutch of the air conditioner compressor located directly under the hood is operated while the car engine is stopped, the magnetic field generated by the electromagnetic clutch will be When we measured the influence of the magnetic field on the geomagnetic sensor, the results were as follows. In other words, if you turn the car in each of the four directions (north, south, east, west, and west) and read the deviation in the direction of the pointer on the compass when the electromagnetic clutch is engaged, the deviation angle when the car is turned north is 0°, When facing south, the deviation angle was 2° westward, when facing east, the deviation angle was 34° southward, and when facing west, the deviation angle was 36° southward. Note that the measurement error at this time is approximately ±2°. The results of this measurement are shown in Figure 1, and as is clear from the figure, the magnetic flux generated by the electromagnetic clutch below the geomagnetic sensor causes the direction of the compass pointer to generally move southward. It can be seen that the deviation becomes very large when the vehicle is located in the east or west direction, and is greatly affected by external disturbances.

From the above measurement results, the direction of the magnetic field when the magnetic flux generated from the electromagnetic clutch placed directly under the hood acts on the geomagnetic sensor installed on the hood is approximately as shown in Figure 2 a and b. It can be thought of as being in the direction from the front to the rear of the vehicle.

In other words, when the front of the vehicle body 1 faces west as shown in FIG. If the direction of the generated magnetic field is vector B, the direction of the resultant vector C will be erroneously detected as the geomagnetic direction by the geomagnetic sensor 2, resulting in a deviation angle θ of 36° from the actual geomagnetic direction A. As a result, the direction of the compass will shift southward. In addition, as shown in Figure 2b, when the front of the vehicle body 1 faces east, the actual direction of the geomagnetic field at that time is to the left with respect to the front of the vehicle body, as shown by vector A, and the electromagnetic field in that case If the direction of the magnetic field generated by the clutch is vector D, the direction of the resultant vector E will be erroneously detected as the geomagnetic direction by the geomagnetic sensor 2, resulting in a deviation angle θ of 34° from the actual geomagnetic direction A. As a result, the direction of the compass indicator will shift to the south.
Furthermore, although not particularly shown, if the front of the vehicle is facing north or south, the actual direction of the earth's magnetic field will be backward or forward with respect to the vehicle, and in that case the direction of the magnetic field generated from the electromagnetic clutch will be the actual direction. The direction of the earth's magnetic field is the same as that of the earth's magnetic field, or vice versa, and the earth's magnetic field is strengthened or weakened, and the direction of the compass's pointer at that time does not go out of order.

Therefore, the above logical result almost coincides with the actual measurement result shown in Figure 1 mentioned above.
It can be explained that when the magnetic flux generated from the electromagnetic clutch located directly under the hood acts on the geomagnetic sensor mounted on the hood, the direction of the magnetic field is approximately from the front to the rear of the vehicle body. .

In the method for preventing disturbance of a geomagnetic sensor according to the present invention, the electric wires (power line ) The wiring process is appropriately performed so that the magnetic field generated by the flow of current through the geomagnetic sensor can cancel out the magnetic field generated from the electrical equipment that is applied to the geomagnetic sensor.

That is, in the above example, in order to cancel the magnetic field in the direction from the front to the rear of the vehicle body that is applied to the geomagnetic sensor mounted on the bonnet due to the electromagnetic clutch disposed directly under the bonnet, the battery is An electric wire connected to the electromagnetic clutch may be placed near the geomagnetic sensor so that the magnetic field generated by current flowing through it is applied to the geomagnetic sensor in a direction from the rear to the front of the vehicle body. Figure 3 shows the state of the magnetic field applied to the geomagnetic sensor 2 at that time. In the figure, _H1 represents the magnetic field due to leakage magnetic flux from the electromagnetic clutch 3, and _H2 represents the magnetic field connected to the clutch 3 from the battery 4. The magnetic fields generated in the geomagnetic sensor 2 section by the electric wires 5 which are wired so as to cross the section where the geomagnetic sensor 2 is installed are shown. In the vicinity of the geomagnetic sensor 2, the magnetic field generated by the electric wire 5 is dominant, and the leakage magnetic flux from the electromagnetic clutch 3 can be effectively canceled to almost zero.

Fig. 4 shows an example in which the wiring of the electric wire 5 is carried out so that the leakage magnetic flux from the electromagnetic clutch 3 can be canceled by the geomagnetic sensor 2. The electric wire 5 is wound in a loop using the upper part of the front bulkhead 6 and around the mounting area of the radiator 7 (the figure shows a wire wound twice). Geomagnetic sensor 2 installed on the bonnet 8 as shown in FIG.
A forward magnetic field H ₂ is applied to the An arrow I in the figure indicates the direction of current flowing through the electric wire 5. Furthermore, after wiring the electric wire 5 shown in Fig. 4, the deviation angles were measured in each of the four directions (north, south, east, and west) under the same conditions as in the case of Fig. 1. , in the east and west directions, the deviation angle was 0°, and in the south direction, the deviation angle was 2° westward, giving very good results.

In addition, since the direction of the magnetic field due to leakage magnetic flux from the electromagnetic clutch installed directly under the bonnet is almost the same as the longitudinal direction of the vehicle body with respect to the geomagnetic sensor installed on the bonnet, other factors such as Fig. 6a,
As shown in FIG. 1B, by wiring the electric wires 5 to the geomagnetic sensor 2 in the left-right direction of the vehicle body, leakage magnetic flux from the geomagnetic sensor can be effectively suppressed. Note that the arrows in the figure indicate the direction of the current flowing through the electric wire 5, and in _FIG . Make it.

Furthermore, if the direction of the magnetic field applied to the geomagnetic sensor due to the magnetic flux generated in an electrical component such as an electromagnetic clutch is oblique, for example, as shown in Figures 7a to 7d, the direction of the magnetic field _H1 will be The electric wires 5 may be wired diagonally or in a loop shape to be processed as appropriate. In addition,
In Figures 6 and 7, there is an electric wire 5 on the back side of the bonnet 8.
However, other things such as the 8th
It goes without saying that the electric wire 5 may be routed inside the engine room 11 as shown in the figure.

In addition, in the case of an alternating current generator, in addition to the field current, there is an output current obtained by power generation as the current that generates magnetic flux, so measures for wiring the electric wires 5 should be taken in consideration of both. (for example, by combining two sets of loop wiring). Also,
When installing the wiring on the back side of the bonnet, please refer to Figure 9a.
It is more effective to route the electric wire 5 between the inner 9 and the bonnet plate 10 as shown in b and c of the same figure, than to route the electric wire 5 outside the inner 9 as shown in FIG. Become something.

As described above, in the method for preventing disturbance of a geomagnetic sensor according to the present invention, when a compass is mounted on a car, magnetic flux generated from various electrical components such as a generator and an electromagnetic clutch for an air conditioner installed in the car is used. According to the direction of the magnetic field applied to the geomagnetic sensor of the compass by the compass, the magnetic field generated by the current flowing through the electric wire of the electrical component can cancel the magnetic field applied to the geomagnetic sensor by the electrical component. This allows the wiring to be processed.
The geomagnetic sensor has an excellent advantage in that it can always accurately detect the geomagnetic direction without being adversely affected by magnetic fields generated from electrical components.

[Brief explanation of drawings]

Figure 1 is a diagram showing the results of measuring the influence of the magnetic field generated by the electromagnetic clutch on the geomagnetic sensor, Figures 2a and b are diagrams showing the influence of the magnetic field generated by the electromagnetic clutch on the geomagnetic sensor, and Figure 3 is a diagram showing the effect of the magnetic field generated by the electromagnetic clutch on the geomagnetic sensor. FIG. 4 is a perspective view showing an example of wiring processing of electric wires according to the present invention, and FIG. 5 is a diagram showing the state in which the magnetic field generated by the electric wires acts on the geomagnetic sensor when viewed from the side. , FIG. 6 a, b and FIG. 7 a, b, c, d are diagrams showing other examples of wiring processing, respectively. FIG. 8 is a diagram showing still another example of wiring processing, and FIG. 9 a, Figures b and c each show an example of wiring on the back side of the hood. 1... Vehicle body, 2... Geomagnetic sensor, 3... Electromagnetic clutch, 4... Battery, 5... Electric wire, 6... Front bulkhead, 7... Radiator, 8... Bonnet,
9...Inner, 10...Bonnet plate, 11...Engine room.

Claims (1)

[Claims] 1 When installing a geomagnetic sensor in a car, wires in the car's electrical components are routed so that they cross the area where the geomagnetic sensor is installed, and the magnetic field applied to the geomagnetic sensor by the magnetic flux generated from the electrical components is reduced. , a method for preventing disturbance of a geomagnetic sensor in which the magnetic field generated by current flowing through the electric wire of the electrical component is canceled out.