JPS59226815A - On-vehicle terrestrial magnetism sensor - Google Patents

Abstract

PURPOSE:To eliminate the influence of magnetization at a railroad crossing and leak magnetic fields from various electric car parts by fitting a terrestrial magnetism sensor at the front or rear edge of the roof of a vehicle where the magnetic field of the vehicle floor and the magnetic field of the roof cancel each other. CONSTITUTION:The vehicle 1 magnetized at a railroad crossing has magnets by the magnetization not only at the floor 1a, but also at the roof 1b. A magnetic field 2a is from the floor 1a, and a magnetic field 3a is from the roof 1b. Those magnetic fields 2a and 3a are mixed and leftward and rightward components of the magnetic fields cancel each other at the front edge A and rear edge B of the roof 1b, so the terrestrial magnetism sensor 4 is fitted there. Consequently, the influence of the magnetic fields due to the railroad crossing magnetization and the influence of magnetic fields from various electric car parts are removed from the sensor 4.

Description

[Detailed description of the invention] The present invention relates to a vehicle-mounted geomagnetic sensor.

An on-vehicle geomagnetic sensor is used, for example, as a compass, which measures the traveling direction of a vehicle by detecting geomagnetism.

As a geomagnetic sensor, for example, Toroidalco≠i type 7
A rack-gate type one is used.

By the way, it is generally considered that it is preferable to attach such an in-vehicle geomagnetic sensor to the 7-spot position on the hood of the vehicle. This is because it is possible to prevent the influence of railroad crossing magnetization. That is, as shown in FIG.
The floor of the vehicle 31 is magnetized by this, but since the direction of the component of the magnetic field at the bonnet mascot position is orthogonal to the geomagnetic sensitive stress direction of the geomagnetic sensor 32, the geomagnetic sensor 32 cannot detect the magnetic field related to railroad crossing magnetization. Therefore, no magnetization error occurs.

However, there is an engine inside the hood of the vehicle.

The geomagnetic sensor 32 installed at the bonnet mascot position detects the leakage magnetic field generated by the above-mentioned electrical components. will be affected by. Therefore, when installing a geomagnetic sensor at the bonnet mascot position, measures must be taken to prevent leakage magnetic fields, which is costly.

Additionally, as shown in Figure 3, there is a suitable location for installing a geomagnetic sensor on the rear side of the vehicle, similar to the bonnet mascot location, but this location is also affected by the cargo in the trunk. This is not preferable as it may cause errors.

In view of the above-mentioned problems, the present inventors have created the present invention in order to effectively solve the problems.

An object of the present invention is to provide an on-vehicle geomagnetic sensor in which the geomagnetic sensor is installed in a location that is completely unaffected by magnetic flux leakage from railroad crossings and various electrical components, in a vehicle equipped with electronic equipment that utilizes the geomagnetic sensor. There is a particular thing.

A feature of the present invention is that the geomagnetic sensor 9 is mounted at a location on the leading or trailing edge of the roof of the vehicle where the magnetic field of the vehicle floor and the magnetic field of the roof cancel each other out.

An embodiment of the present invention will be described below based on the accompanying drawings.

Figure 1 is a diagram showing the state of level crossing magnetization in a vehicle, Figure 2
The figure shows the mounting location of the geomagnetic sensor.

As shown in Figure 1, a vehicle 1 magnetized at a level crossing is located at the floor 1 of the vehicle.
A magnet is generated not only in the roof 1b but also in the roof 1b due to magnetization.

In FIG. 1, where these magnets are designated as 2 and 3, 2a is the magnetic field due to the magnet 2 on the floor 1a, and 3a is the magnetic field on the roof 1.
This is the magnetic field caused by the magnet 3 in b. According to the magnetic fields 2a and 3a, the leading edge A and the trailing edge B of the roof 1b are the locations where the components of each magnetic field in the left and right directions in the figure cancel each other out due to the combination of these magnetic fields.
occurs in

Therefore, if a geomagnetic sensor 4 is attached to the front or rear edge of the roof 1b of the vehicle 1 on the indoor or outdoor side of the roof as shown in FIG. The influence of leakage magnetic fields from various electrical components can be eliminated, and the geomagnetic sensor can detect only geomagnetism.

As is clear from the above description, according to the present invention, by arranging the geomagnetic sensor used such as a compass on the front or rear edge of the roof of the vehicle, magnetization and control of various electrical components when passing through a railroad crossing is achieved. The influence of the leakage magnetic field on the geomagnetic sensor can be eliminated, and the output operation of the geomagnetic sensor can be made accurate.

In particular, it is not necessary to provide a special correction circuit or the like in order to make the output signal of the geomagnetic sensor accurate, and it is sufficient to simply select the mounting location, so it can be realized at low cost.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the state of level crossing magnetization in a vehicle, Figure 2
The figure shows the installation location of the geomagnetic sensor according to the present invention,
FIG. 3 is a diagram for explaining problems related to the mounting location of a conventional vehicle-mounted geomagnetic sensor. In the drawing, 1 is a vehicle, 2.30 is a magnet on the car body floor magnetized by level crossing magnetization, 3 is a magnet on the car body roof due to level crossing magnetization, and 4
, 32 are geomagnetic sensors. Patent applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] In a vehicle such as an automobile equipped with an electronic device that utilizes a geomagnetic sensor, the geomagnetic sensor is installed at a location on the leading or trailing edge of the roof of the vehicle where the magnetic field of the vehicle floor and the magnetic field of the roof cancel each other out. An in-vehicle geomagnetic sensor featuring: