JPH11242073A - Sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sensor sensitivity and simplify a magnetic circuit, by disposing a plurality of magnetic field sensitive elements in a single casing. SOLUTION: At least two magnetic field sensitive elements 12, 13 are disposed in only one easing 11. In other words, the sensor has, for example, the casing 11 made of plastic by injection molding technology. The two magnetic field sensitive elements 12, 13 are disposed as close as possible in the casing 11. The sensitive faces of the two magnetic field sensitive elements 12, 13 are closely adjacent by making the casing 11 common. As a result, these sensitive faces can detect the substantially same magnetic field, and the characteristic curves of the two magnetic field sensitive elements 12, 13 are substantially ideal. In addition, an incoming magnetic flux line or an outgoing magnetic flux line is relatively strongly converged, and sensitivity of the sensor 10 is improved. Furthermore, the configuration of a structure is small and a manufacturing cost is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a sensor comprising a casing and at least one magnetic field-sensitive element.

[0002]

2. Description of the Related Art The measuring apparatus described in the publication DE-A-196 34 338.
A magnetic field sensitive element arranged in a gap between two magnetic conducting elements is described. In order to make a so-called redundant measurement (for reliable measurement), two magnetically sensitive elements are in each case juxtaposed in one unique housing. However, the course of the magnetic flux is not uniform over the entire width of the casing, so that the two elements
Another magnetic flux line having different uniformity is detected. This causes an error in the measurement. This error cannot be avoided even if the two elements are arranged as close as possible due to the width of the casing.

[0003]

It is an object of the present invention to avoid the above-mentioned disadvantages.

[0004]

This object is achieved by an arrangement in which at least two field-sensitive elements are arranged in only one housing.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sensor according to the present invention; That is, due to the common casing, the two magnetic field sensitive elements, the sensing surfaces of these elements, are very closely adjacent. This makes it possible for these sensing surfaces to detect almost identical magnetic fields, so that the characteristic curves of the two elements have almost ideal identical courses. Unlike the prior art, individually packaged components require a relatively small area. As a result, the magnetic flux lines entering or leaving the element are focused relatively strongly. Also, the gap in which the sensor is to be placed can be kept relatively small. Due to the large magnetic induction acting on the elements of the sensor, the measurement sensitivity of the sensor is improved. In addition to the reduced form of the structure, the manufacturing costs are also reduced. The two elements can be arranged on one printed wiring board. The magnetic circuit can be simplified by focusing the magnetic flux lines.

By means of the dependent claims, claim 1
Other embodiments and improvements of the sensor having the configuration described in are possible.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention.

FIGS. 1 and 2 depict a sensor at 10. The sensor has a casing 11 made of plastic, for example, by injection molding technology. As close as possible to each other in the casing 11
Two magnetic field sensitive elements 12, 13 are arranged. The two magnetic field sensitive elements 12 and 13 have the same configuration and each have a unique terminal 14. This means that these elements can operate completely independently of each other. The magnetic field sensitive elements 12, 13 are, for example, field plates, magnet transistors or Hall elements. What is important here is that the output signal of the field-sensitive element has a linear dependence on the magnetic induction B as much as possible. In the embodiment of FIGS. 1 and 2, for example, a Hall element is used. In this case, the two Hall elements 12, 13 can be arranged on a common (not shown) printed wiring board. Particularly advantageously,
Due to the common casing 11, the two elements 12, 13 can be arranged almost directly or directly next to one another.

FIG. 3 shows how the magnetic flux generated from, for example, a permanent magnet (not shown) is focused in the area of the sensor 10 due to the special shape of the magnetic flux conductor 15. . As is well known, the two magnetic flux conductors 15
A gap 16 exists between the sensor 10 and the sensor 10.
Is arranged. In order to focus the magnetic flux, the air gap 16
The end of the magnetic flux conductor portion 15 on the side oriented in the direction is formed in a conical shape. The front face of the conical end of the magnetic flux conductor 15 is in this case adapted to the width of the elements 12, 13 which are arranged adjacently in the housing 11 of the sensor 10. With this configuration, the magnetic flux is focused on the two elements 12, 13, and
Optimal measurement value detection is achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (a cross-sectional view taken along line II of FIG. 2) of an embodiment of the present invention.

FIG. 2 is a top view of an embodiment of the present invention.

FIG. 3 is a schematic view of an apparatus for focusing magnetic flux lines in the area of a magnetic field sensitive element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sensor 11 Casing 12, 13 Magnetic field sensitive element 14 Terminal 15 Magnetic flux conductor 16 Air gap

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Thomas Klotzbucher Germany Rudersberg Oberlahr Weiler 9

Claims (4)

[Claims] 1. A sensor (1) comprising a casing (11) and at least one magnetic field sensitive element (12, 13).
In (0), the sensor characterized in that at least two magnetically sensitive elements (12, 13) are arranged in only one casing (11). 2. The sensor according to claim 1, wherein the magnetic field sensitive elements are juxtaposed as closely as possible. 3. The sensor according to claim 1, wherein the magnetic field sensitive elements are independent of one another. 4. The sensor according to claim 1, wherein the at least one magnetic field sensitive element is a Hall element.