Pressure detector.

p0001The invention relates to a pressure sensor according to the preamble of the main claim.

p0002Such pressure sensors are known (prospectus KMK, sensors and measurement-processing systems for the industry). They have an existing stainless steel metallic housing in the form of a provided with an external thread and a hexagonal Einschraubbolzens, at its front side the membrane of the fluid-filled pressure chamber is mounted in which is arranged as a sensor of the pressure sensor chip. This is connected in the closed pressure chamber by means of electrically insulated glass into guided terminals disposed on the in the rear (outer) part of the pressure sensor evaluation circuit, wherein the pressure sensor chip is arranged on a base, whereby a comparatively large amount of fluid is required to fill the pressure chamber.

p0003Apart from the fact that even the production of electric glass insulation for the connections is costly and leads to a high reject the expensive stainless steel case, this is even more true for the electrical evaluation circuit comprising the pressure sensor pressure sensor which in the finished state only for functionality is checked. In addition there are the operations that the pressure chamber is evacuated and then filled with the fluid. Therefore, the known pressure sensors are expensive to manufacture, and especially for larger accuracies difficult adjustable.

p0004The invention is based, according to the preamble of the main claim in sufficient detail that is also easy to prepare, propose a simple adjustable transducer on the object. This object is achieved erfndungsgemäß with a pressure sensor according to the preamble of Hauptanßpruchs by its characterizing features. Thus, on both sides by the arrangement of two Hall elements in the differential circuit, ie in series and assembly, preferably diametrically with respect to the bar magnet is achieved that an increased output is obtained. This arrangement also ensures that the Hall generator differently proposed at not constant distance of the bar magnet while swinging the membrane, the Hall elements, high voltages, this mechanical parallax is compensated by the series connection quasi. The Hall elements are hereby preferably at the same height and the rod element, so that during the disengagement of the magnet in this position when swinging the separation membrane gives symmetrically to them about linear output voltage characteristic of the entire circuit. Incidentally, is located in the pressure air, so that it a filling with fluid and evacuation is not required.

p0005In advantageous embodiment of the bar magnet is mounted on a non-magnetic intermediate piece to the diaphragm and the carrier plate with the Hall elements in the transducer screwed. Due to this Einschraubbarkeit preferably with a fine thread is easy and simple and balancing the zero point (center position of the bar magnet with respect to the two Hall elements) achievable.

p0006In a preferred embodiment the poles of the bar magnet (15) perpendicular to the vibration direction (16) and the Hall elements are perpendicular to the extension of the bar magnets disposed on one side thereof as well as in swinging direction one behind the other. The active surfaces of the Hall elements lie in a common plane which is parallel to the vibration direction and perpendicular to the extension of the bar magnet.

p0007Further, the diaphragm is designed as a thick disk of aluminum or stainless steel with an annular recessed thin and the actual membrane forming region.

p0008Expedient refinements and developments of the invention are characterized in the dependent claims.

p0009A preferred embodiment will now be described with reference to the drawing. This shows:<ul><li>1 shows a pressure sensor in schematic cross section;</li><li>Figure 2 is a plan view II-II of Figure 1, with removed membrane.</li><li>3 shows a second embodiment of a pressure sensor in a schematic cross-section, and</li><li>Figure 4 shows the arrangement of the magnet and the Hall elements in a perspective view</li></ul>

p0010The designated overall by 5 pressure sensor has a metallic housing 6, with a closed pressure chamber 7, which is sealed by a membrane. 8

p0011In the pressure chamber 7, a total of 9 designated carrier plate is provided on its side facing the diaphragm 8 side has a formed as an insulator support member as a hollow cylinder section l7, on its inner casing l0 two Hall elements are arranged so that their active layers in parallel to the vibration direction L6 are run and facing each other. The connections of the Hall elements ll l0 are pressure tight through a passage l2 and ushered electrically insulated and a - connectable electrical evaluation circuit - not shown. The metallic housing 6 is further provided with an internal fine thread l3, in which the carrier plate 9 which is provided with a corresponding external thread, can be screwed. To the membrane 8 is a bar magnet in the pressure chamber 7 approximately centrally on a non-magnetic intermediate piece L4 L5 disposed, whose two poles are arranged in linearly in the direction of oscillation of the diaphragm l6 eighth Further, the bar magnet is l5 l0 and symmetrically arranged symmetrically with respect to both the same height arranged Hall elements to the horizontal center plane. The bar magnet l5 is designed as a vertical circular cylinder and the two Hall elements are arranged diametrically opposite one another with clearance to the jacket of the bar magnet l5.

p0012The two Hall elements l0 are arranged behind one another electrically in a differential circuit.

p0013Fig. 2 shows a plan view of the support plate 9 according to view II-II in Fig. L. Schematically with l5 of the bar magnet is designated. With play on this rich, the two Hall elements l0 on the support plate. 9

p0014Figure 3 shows a schematic cross section through a pressure sensor. In the actual, made of aluminum or stainless steel thick slice is annular recessed thin to form the actual membrane. 8 In the central region of the diaphragm, the magnet is arranged l4. Laterally, the Hall elements are l0 disposed on one side of the magnet l4 and poured in a cast body, generally designated l8. The arrangement of the magnet and the Hall elements l4 l0 is shown more particularly in Fig. 4 in a perspective view.

p0015It can be seen that the two poles of the magnet extend perpendicular to the vibration direction L6. The Hall elements are vertical on one side thereof L9 arranged one behind the other on the extension of the two poles of the total cuboidal bar magnets in the vibration direction L6, with their active surfaces lie in a common plane which is parallel to the vibration direction and perpendicular to the extension of the bar magnets l5.