Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
  • G01D11/24—Housings ; Casings for instruments
  • G01D11/245—Housings for sensors

Definitions

• the invention relates to a magnetic field sensor, in particular a speed and / or direction of rotation sensor for a vehicle or for the drive train of a vehicle according to the preamble of claim 1, as has become known for example from DE 101 29 222 A.
• This document discloses a magnetic field sensor with a support element made of metal, on which a holder for a sensor element is fixed in a predetermined position. About the type of positioning of the sensor element in the holder makes the document no further details. For this purpose, it is merely stated that the holder is hermetically enclosed by an encapsulation together with the sensor element inserted therein.
• a wheel bearing sensor for measuring rotational or angular movements is known, the sensor housing encapsulated together with the sensor head as a unit.
• a sensor element is applied to a carrier serving as a permanent magnet and embedded together with this in the potting compound, with the risk that the sensor element is damaged during the wrapping with plastic by the stresses or deformations occurring.
• the invention has for its object to provide a magnetic field sensor, which is characterized on the one hand by very small tolerances in the positioning of the sensor element and on the other hand the risk of damage to the Sensor element avoids the occurring in the plastic cladding thermal and mechanical loads.
• the characterizing features of claim 1 wherein the positioning of the sensor element in a pocket-like recess of the holder on the one hand exact positioning is ensured and on the other hand mechanical stresses during encapsulation of the holder with the sensor element by its support in the recess are largely excluded ,
• the sensor element is formed as a flat IC chip component and placed in a correspondingly shaped, extending substantially perpendicular to the axial direction of the sensor recess, because in this case a particularly good support and exact positioning are made possible by the flat large areas of the sensor element
• the holder has a preferably slot-like opening for introducing the sensor element into the recess, so that the sensor element is inserted into the recess with little play and can be positioned by the support of its connection lines at the edge of the slot-shaped opening without further aids.
• the arrangement of the recess for the sensor element immediately behind the reading surface of the finished magnetic field sensor, the air gap between the sensor element and an associated encoder is minimized.
• the holder itself is preferably injection molded from thermoplastic material and expediently has at least in the region of the sensor element fuser ribs, whereby a good connection between the holder and the outer potting compound and an exact positioning and locking are ensured in the potting compound.
• the holder in the axial direction next to the recess for the sensor element a molded clamp for the Receiving a magnet and optionally an associated diffuser for the generation of the sensor field has, since in this case the sensor element can be locked directly in the recess by the magnet and optionally the lens in the axial direction of the holder without additional further holding elements.
• Figure 1 is a view of the magnetic field sensor according to the invention, partly in section, and
• FIG. 2 shows a view of the underside of the magnetic field sensor shown in Figure 1.
• FIG. 1 denoted by 10 is a magnetic field sensor, which as a whole is encapsulated with a sheathing 12 made of thermoplastic material. Inside, there is a holder 14, likewise injection-molded from thermoplastic material, which has melting ribs 16 for secure integration of the holder 14 into the casing 12.
• the thermoplastic used for both the casing 12 and the holder 14 is the same polyamide material.
• connection-side end of the holder 14 two connecting cables 18 and 20 are injected, the stripped ends are connected by means of a respective crimp connection 21 with fittings 22 and 24. These fittings are initially in one piece to facilitate the positioning of the electrical connection parts and then by the separation of the connecting parts 26, 28 against each other electrically isolated.
• the free ends of the connecting pieces 22 and 24 are connected in the region of a window-like opening 33 in the holder 14 by welding or soldering with connecting leads 30 and 32 of an IC sensor element 34. To suppress voltage peaks, the connection lines 30 and 32 are bridged by a capacitor 36.
• the magnetic field sensor whose so-called read side, which is arranged adjacent to a donor, not shown in the drawing, for example, an alternately provided with teeth and tooth gaps ferromagnetic encoder wheel.
• the magnetic field necessary for detecting the position of such a donor wheel is generated by a permanent magnet 38 and an associated lens 40.
• the permanent magnet 38 and the lens 40 are laterally positioned and locked by two elastically deflectable arms 42 and 44 of the holder 14.
• the permanent magnet 38 and the lens 40 are arranged between a projection 46 of the holder 14 and the reading-side end wall 48 that the sensor element 34 with a small clearance through a slot-shaped opening 49 in the space between the lens 40 and the Front wall 48 fits.
• the sensor element 34 is in turn positioned and supported at the upper end by the bent ends of its connecting lines 30 and 32 and at its lower edge and on both sides by an axially projecting edge 52 on the end wall 48.
• the holder 14 is thus designed in the region of the sensor element 34 such that it rests in the pocket-like recess 50 with the reading side on the inside of the end wall 48, the outside of the plastic envelope is applied to the not visible in the drawing tool wall, whereby the IC Sensor element 34 is supported on its entire large area. This results in a non-deformable position of the sensor element 34 in the holder 14, so that when spraying the outer sheath 12 of the sensor 10, even at high pressures and high friction during filling of the injection tool no distortion or deformation of the IC sensor element 34 occur and this is thus safely protected next to accurate positioning against damage.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Transmission And Conversion Of Sensor Element Output (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
• Measuring Magnetic Variables (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=36087735

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (22)

Family Cites Families (17)

• 2005
  • 2005-03-22 DE DE200510012709 patent/DE102005012709A1/de not_active Withdrawn
• 2006
  • 2006-01-26 WO PCT/EP2006/050464 patent/WO2006100143A1/de not_active Application Discontinuation
  • 2006-01-26 MX MX2007011719A patent/MX2007011719A/es active IP Right Grant
  • 2006-01-26 CN CN200680009211A patent/CN100578157C/zh not_active Expired - Fee Related
  • 2006-01-26 EP EP06707852A patent/EP1864090A1/de not_active Withdrawn
  • 2006-01-26 JP JP2008502357A patent/JP2008533494A/ja active Pending

Non-Patent Citations (1)

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