Patent Application
20110273854
The invention relates to a magnetic field sensor comprising a housing which includes a plug and encloses sensor electronics. Such sensors are used in motor vehicles, e.g. to measure linear displacement or the angular position of a magnetic position sensor.
The problem addressed by the present invention is that of demonstrating a way to more economically manufacture a magnetic field sensor suitable for use in motor vehicles.
This problem is solved by a magnetic field sensor having the features indicated in claim 1. Advantageous refinements of the invention are the subject matter of dependent claims.
A magnetic field sensor according to the invention comprises a two-pieced housing composed of a housing top part, which has a single opening, and a housing base which closes the opening. Contact pins of a plug, i.e. a male connector, extend outwardly from the housing base which also contains the sensor electronics.
A magnetic field sensor according to the invention can be manufactured at low cost since the electronics can be preinstalled on the housing base, and then only two more parts need to be joined, namely the housing top part and the housing base comprising the sensor electronics and the contact pins. Particularly advantageously, the sensor electronics enclosed by the housing can be protected against harmful environmental influences, such as splash water and the like, in a simple manner by the combination of a housing top part, which has a single opening, and a housing base which closes the opening. Advantageously, complex measures such as sealing rings or filling the housing interior with an electrically insulating protective compound can be omitted.
The sensor electronics of a magnetic field sensor according to the invention can contain e.g. a Hall sensor or a resistor element, the electrical resistance of which changes depending on a magnetic field. Materials for such resistor elements are known per the keyword “giant magnetic resistance”. Other methods for magnetic field measurement, such as coils or the like, can also be used for a magnetic field sensor according to the invention.
The present invention furthermore relates to a system composed of such a magnetic field sensor and a female connector which fits the plug of the magnetic field sensor and can be inserted into a section of the housing top part of the magnetic field sensor. When the magnetic field sensor is connected to the female connector, the female connector provides an additional seal which also hinders splash water or the like from entering the interior space of the magnetic field sensor. This is possible because the female connector encloses the housing top part of the magnetic field sensor inserted therein. The female connector preferably comprises a sealing lip which rests on the circumference of the housing top part.
According to an advantageous refinement of the invention, the housing top part comprises on the outer side thereof at least one holding element for holding the female connector. Snap-in projections or other snap-in elements which hold, in a form-fit manner, a female connector enclosing the outer side of the housing are particularly suitable, for example.
According to a further advantageous refinement of the invention, the sensor electronics are disposed on a printed circuit board which is mounted on the housing base. In this manner the sensor electronics can be advantageously connected to the housing base to form an easily handled assembly which then needs only to be joined to the housing top part. The contact pins of the plug can be pressed into openings in the printed circuit board, or they can be soldered to the printed circuit board or connected using connecting wires.
Preferably the housing base grips the printed circuit board on opposite edges. It is thereby easier to fasten the printed circuit board to the housing base. As an alternative or in addition thereto, the housing base can be provided with raised areas which engage in positioning holes in the printed circuit board.
According to a further advantageous development of the invention, the housing base is pressed into the housing top part. A connection, which is resistant to splash water, between the housing base and the housing top part can therefore be obtained in a simple manner. To fasten the housing base in the housing top part in a particularly reliable manner and in a defined position, the housing base can be snapped into position with the housing top part. The housing base can be clipped into the housing top part, for example.
Further details and advantages of the invention are explained using an embodiment, with reference to the attached drawings. In the drawings:
The magnetic field sensor shown comprises a two-pieced housing, i.e. a housing composed of only two pieces. The two-pieced housing is formed of a housing top part 1, which has a single opening, and a housing base 2 which closes the opening. Housing base 2 comprises contact pins 3 of a plug. Housing top part 1 is also used as the plug housing and can comprise guides for a female connector. Housing top part 1 and housing base 2 are made of plastics, e.g. by injection molding.
Housing base 2 comprises a printed circuit board 4 on which sensor electronics 4a for magnetic field measurement are disposed. Sensor electronics 4a can comprise a Hall sensor, for example. Housing base 2 grips printed circuit board 4 on opposite edges. In the embodiment shown, opposite lateral surfaces of printed circuit board 4 are covered by housing base 2. Housing base 2 therefore comprises a recess into which printed circuit board 4 is inserted. When printed circuit board 4 is inserted, contact pins 3 of housing base 2 can be pressed into printed circuit board 4. It is also possible to connect contact pins 3 to printed circuit board 4 by soldering. The housing base can be injection molded around the contact pins 3. It is also possible to press the contact pins into housing base 2.
To install the magnetic field sensor, housing base 2 is pressed into housing top part 1 and snaps into a defined position in the interior of housing top part 1.
Housing top part 1 can comprise, on the outer side thereof, one or more holding elements 5 for holding a female connector 9 shown schematically in
As shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 020 119.7 | May 2010 | DE | national |
