DE102011081222A1 - Method for producing sensor assembly e.g. rotational speed sensor assembly mounted in motor vehicle, involves placing magnetic field sensor in receptacle of housing that is arranged adjacent to magnetic flux collector - Google Patents

Abstract

The method involves forming a magnetic flux collector (3) in the shape of pin. The magnetic flux collector is partially encapsulated with a thermoplastic or thermosetting material (4). A housing (2) is provided with a receptacle (5) for a magnetic field sensor (6), and is arranged adjacent to magnetic flux collector. The magnetic field sensor is placed in receptacle of housing. An independent claim is included for sensor assembly.

Description

The present invention relates to a method for producing a sensor assembly according to the preamble of claim 1. Furthermore, the present invention relates to a sensor assembly according to the preamble of claim 9.

In the prior art is from the document DE 10 2007 018 238 A1 a sensor arrangement is known, in which the measuring sensitivity of a magnetic field sensor, in particular in the form of a differential Hall sensor is increased by a platelet-shaped flux guide, which is arranged adjacent to the differential Hall sensor. As a result, the effective range of the sensors corresponding to a distance to a rotating, magnetic pole wheel, which acts as a signal source, compared to a conventional arrangement without flux guide can be increased.

However, a thin flux guide designed in this way requires complex handling in the course of producing a sufficiently media-tight and robust sensor for use in the motor vehicle sector, for which purpose a plurality of injection molding operations are required on a regular basis.

Proceeding from this, the present invention has the object to overcome the above-described disadvantages of the prior art and to propose a method for producing a sensor assembly which allows for simple component handling the production of a robust and especially media-dense sensor assembly and to provide a sensor assembly, which is simple and inexpensive can be made.

This object is achieved by the features of claim 1 and the features of claim 9. Advantageous embodiments and further developments are the subject of the dependent claims.

According to the invention, a method is proposed for producing a sensor system or a sensor module, in particular a speed sensor module, with a magnetic field sensor and a flux guide element cooperating therewith. The magnetic field sensor may in the context of the present invention comprise one or more Hall elements, in particular Hall plates, and e.g. integrally formed as an IC, i.e. as a Hall IC chip. The magnetic field sensor may alternatively be e.g. Have field plates. Preferably, the magnetic field sensor is formed as a differential Hall sensor and further preferably provided to cooperate with a spaced therefrom, in particular rotatable magnetic rotor for speed determination together. The differential Hall sensor preferably has at least two mutually spaced Hall sensor elements, which provide a difference signal, in particular a differential voltage signal. The Hall sensor elements or Hall plates in this case preferably have a common plane of extent.

The method according to the invention comprises the steps of: A) providing the flux-conducting element in the form of a magnetically flux-conductive, in particular pin-shaped or rod-shaped, carrier body; B) forming a Vorumspritzlings with a receptacle for the magnetic field sensor adjacent to the carrier body by positioning and at least partially encapsulating the carrier body with a thermoplastic or thermosetting plastic; C) Arranging the magnetic field pickup in the recording. By o. A. Method steps A) to C) can be easily formed a sensor assembly in which the magnetic field sensor by mere insertion or e.g. Sticking is stored stable position. In a further step, e.g. a housing are attached.

The flux guiding element provided in step A) is in this case advantageously uncomplicated a body of simple geometry, in particular a rod or pin-shaped body, which is intended to carry the components of the sensor assembly - in particular in the course of the production of the same - and insofar a carrier body. The carrier body preferably has a cylindrical shape which allows easy positioning and alignment in a tool, alternatively e.g. Cuboid shape or a different shape, in particular preferably a shape which allows a tight transition to overmolding material in the course of an encapsulation easily. The carrier body is preferably made of a ferromagnetic material, in particular a magnetizable metal, in order to provide a magnetic flux conductivity.

The carrier body is first held or positioned in step B), in particular positionally stable. In the course of positioning, the carrier body is suitably aligned and accommodated, for example, in a tool, in particular in a thermoplastic tool. For this purpose, in particular a provided for positioning end of the support body is used, which can be fixed or clamped. Subsequently, thermoplastic or thermoset molded on the support body now, ie the support body at least partially encapsulated with thermoplastic or thermosetting plastic. In the course of extrusion coating, a pre-molded part is formed with a receptacle, which is provided for the arrangement of the magnetic field sensor. The receptacle is formed in the form of a recess or a recess, in particular a trough-shaped depression, which in particular with the shape of the Magnetic field sensor corresponds and further allows in particular a positive connection with the lateral surface. In the recording, the magnetic field sensor can be arranged gravity supported and held.

In the recording thus formed, the magnetic field sensor advantageously simple, especially stable in position used or embedded, at the same time an orientation of the same is made possible in the intended end position. Preferably, the receptacle is formed adjacent to an end face of the carrier body against which the magnetic field pickup can reach the arrangement after being arranged in the receptacle. In a preferred embodiment, the end face is an end face of the particular pin-shaped carrier body which is opposite to an end of the carrier body provided for positioning. The end face preferably provides a flat surface, so that a simple and uniform contact of the magnetic field sensor is made possible.

In particular, after curing of the molded thermoplastic or thermoset magnetic field sensor is introduced in a further step C) in the recording of the pre-molded part formed in step B). This can be done preferably by mere insertion, if necessary, a slight clamping force between the magnetic field sensor and the recording can be set. It is conceivable, e.g. also to arrange the magnetic field sensor adhesive. After being arranged in the receptacle, the magnetic field sensor can now interact with the flux guide element in the form of the carrier body within the sensor assembly manufactured in a simple manner as described above.

In the context of the present invention, the further step D) is also particularly preferably provided: positioning the carrier body and at least partially encapsulating the magnetic field sensor and the pre-molded part with a duroplastic. As a result, the magnetic field sensor can be easily encapsulated or enclosed and, in particular, caught in the receptacle, whereby a media-tight and robust sensor technology can be created.

The carrier body is in turn supported or positioned in step D), in particular positionally stable. In the course of positioning, the carrier body is suitably aligned and e.g. taken in a further tool, in particular a thermoset tool. For this purpose, in turn, the - used in particular unumspritzte - positioning of the carrier body, in particular clamped. The positioning for the encapsulation with thermosetting plastic is provided in such a way that the molded thermoplastic or duroplastic of the pre-molded part can be encapsulated on all sides.

Subsequently, thermoset can be injected onto the pre-molded part including the magnetic field pickup attached thereto, i.e. the same are at least partially encapsulated with a thermosetting plastic. In the course of the encapsulation with thermoset a particularly robust housing can be formed in a simple manner, in particular with integral fasteners.

In the context of the present invention, it is provided that the magnetic field sensor can be suitably contacted in order to be able to pick up a measurement signal. For this purpose, contacting means of the magnetic field sensor arranged in the receptacle, in particular conductor elements, such as e.g. Conductor beads, with Ankontaktiermitteln for contacting the sensor assembly formed, in particular conductor elements in the form of e.g. Strands or lead frames, permanently connected, e.g. by welding or laser welding, crimping or by soldering. The Ankontaktiermittel the magnetic field and / or Ankontaktiermittel attached to the sensor assembly can be encapsulated in step D), ie. with the exception of contacts for external connection purposes, i.e. at least partially. Thus, the Ankontaktiermittel can be easily isolated electrically and at the same time protected against overuse.

Alternatively or additionally, it may be provided in the context of the present invention to at least partially encapsulate conductor structures for electrical connection of the magnetic field sensor in step B), i.e. with thermoplastic or thermoset. For this purpose, Ankontaktiermittel can be positioned and encapsulated in the form of conductor structures together with the carrier body in a tool. The conductor structures can then assist in particular in the positioning for encapsulation with thermoset in step D). In this case, a conductor structure in the form of stamped grid is preferably used. In the case of an encapsulation, the connection ends which have been left free can subsequently be permanently connected, preferably welded or laser-welded, to contact-fixing means of the magnetic field sensor arranged in the receptacle.

It is provided in each case that the magnetic field sensor is advantageously contacted after arranging in the receptacle to Ankontaktiermittel the sensor assembly, in particular insofar as in this case the magnetic field sensor is already provided position-stabilized and aligned.

Also proposed according to the invention is one which has been formed in particular as described above and which has been described above Process imageable sensor module. Such has a particular pin-shaped carrier body, on which a thermoplastic or thermoset molded, by means of which the receptacle for the magnetic field sensor adjacent to the carrier body is formed, wherein the carrier body cooperates flux-conductively with the magnetic field sensor.

As described above for the method, the magnetic field sensor is preferably arranged on an end face of the particular pin-shaped carrier body, in particular that end face, which is opposite to the intended for inclusion in a tool free end or positioning. The receptacle is preferably formed corresponding to the magnetic field sensor and in particular provided for a positive connection with a lateral surface thereof. The receptacle is preferably formed as a recess or recess in the form of a cavity.

In the context of the present invention, the pre-molded part as well as the magnetic field sensor received thereon are preferably encapsulated at least partially with a duroplastic, in particular in such a way that the molded-on thermoplastic or duroplastic, including the magnetic field sensor, is encapsulated. In this way, a media-dense sensor module can be provided, wherein the thermoset can simultaneously form a robust housing.

In an embodiment of the magnetic field sensor having at least one plate-shaped Hall element, in particular Hall elements designed as transversal sensor plates, it is provided that in particular all Hall elements of the magnetic field sensor extend substantially parallel to the adjacent end face of the carrier body. Thus, the carrier body can guide the relevant for a measurement vertical component of a magnetic flux to increase a sensitivity particularly suitable to the sensor plates or Hall elements.

When forming the magnetic field sensor as a differential Hall sensor is preferably provided that the diameter of the carrier body is selected such that the diameter is at least as large as the distance between two Hall elements of the differential sensor added to the positioning tolerance of the carrier body on the differential sensor. More preferably, the diameter of the carrier body is to be chosen minimal, d. H. preferably as large as the distance between two Hall elements of the differential sensor added to the smallest value of the positioning tolerance of the carrier body on the differential sensor. As a result, the carrier body can be positioned more accurately in the tool. Furthermore, a higher flux density can be achieved by the concomitant concentration of the magnetic flux over a smaller area.

It is proposed that contact-contacting means of the magnetic field sensor, in particular a stamped grid, are at least partially encapsulated by the molded thermoplastic or duroplastic and / or the molded thermoset, i. as stated above in the context of the method.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawings, which show details essential to the invention, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings. Show it:

1 by way of example a sectional view of a sensor module produced by means of method steps A) to C);

2 to 4 further views of the sensor assembly according to 1 ;.

5 by way of example, a sectional view of a means of the sensor assembly according to the 1 to 4 using the further step D) manufactured sensor assembly according to an embodiment of the invention;

6 to 8th further views of the sensor assembly according to 5 ; and

9 an example of a view of a sensor assembly according to another embodiment of the invention.

In the following description of the figures, the same elements or functions are provided with the same reference numerals.

The 1 to 4 each show a particular unhoused sensor assembly 1' , which in the course of the production of a sensor assembly 1 in the form of a speed sensor assembly according to 5 to 8th is obtained by the method steps A) to C).

The sensor assembly 1' has a Vorumspritzling 2 from a carrier body 3 and a molded thermoplastic 4 on. Alternatively, instead of the thermoplastic 4 a duroplast be sprayed. The carrier body 3 is designed as a flux-conductive ferromagnetic cylinder pin, which end flat surfaces or end faces 3a , b, cf. 1 ,

For the production of the sensor assembly 1' respectively. 1 becomes the carrier body 3 which is provided in a first step A) of the method according to the invention, subsequently positioned in a step B) in a transfer molding tool or thermoplastic tool (thermosetting tool). In the course of positioning, the carrier body 3 aligned and on the front side 3b fixed adjacent to the alignment or held positionally stable.

The carrier body supported in this way 3 is now partially with a thermoplastic (thermoset) 4 overmolded, wherein on the carrier body 3 a recording 5 for a magnetic field sensor 6 is formed in the form of a differential Hall sensor ICs, eg 1 . 2 . 4 , The shape of the picture 5 in this case corresponds to that of the magnetic field sensor 6 so that the magnetic field pickup 6 stable in position and can be recorded positively, s. 2 and 4 , Like that 1 to 4 can still be seen in the course of the encapsulation with thermoplastic (thermoset) 4 continue structures 4a on the carrier body 3 created, which in the definition of Ankontaktiermitteln 6a or conductor elements of the magnetic field sensor 6 support and secure against movement within the molded thermoset.

The magnetic field sensor 6 is in a step C) - after curing of the thermoplastic (thermoset) 4 - in the picture taken 5 introduced by inserting and is hereafter particularly gravitational support stable in position in the recording 5 added. In particular 1 can be seen here is the magnetic field sensor 6 directly on the front side 3a of the carrier body 3 in particular in such a way that its Hall elements or transversal Hall plates 6b parallel to the face 3a extend so that the carrier body 3 flux-conducting with the magnetic field sensor 6 can interact.

The diameter d of the carrier body 3 is chosen such that the diameter d is at least as large as the distance between two Hall elements 6b of the differential Hall sensor 6 added to the positioning tolerance of the carrier body 3 at the differential Hall sensor 6 ,

The peripheral components 6c of the magnetic field sensor 6 in the form of connection means 6a and a capacitor 6d are here outside the recording 5 arranged, wherein the connection means 6a on strands or connection means 7 the sensor assembly 1' respectively. 1 , which for connection to the connection means 6a provided on the one hand and external connection means on the other hand, are welded electrically contacting. The connection means 7 be after the insertion of the magnetic field sensor 6 in the recording 5 at the connection elements 6a of the magnetic field sensor 6 Ankontaktiert, ie after step C) or before step D), which will be explained below.

The 5 to 8th show the sensor assembly 1 , which by means of the sensor assembly described above 1' is formed. The sensor assembly 1 has a media-tight housing 8th on, which by means of a thermoset 9 is made. The housing 8th has integral fasteners 9a in the form of holes on which the fixing of the sensor assembly 1 at an intended installation site.

The thermoset 9 surrounds the molded in step B) thermoplastic (thermoset) 4 as well as in the recording 5 arranged magnetic field sensor 6 encapsulating and in particular advantageous media-tight. Next to the magnetic field sensor 6 Here are also its peripheral components 6c , ie the connection means 6a , as well as the capacitor 6d of molded thermoset 9 surrounded and so far on the sensor board 1 set in the intended position, the same by the thermoset 9 Moreover, they are advantageously protected against environmental influences.

For overmolding with duroplastic 9 becomes the carrier body 3 in a step D) of the manufacturing process in a thermoset tool positioned, ie aligned and fixed. For this purpose, in turn, the end portion of the carrier body 3 which is free of thermoplastic (thermoset) 4 is, adjacent to the front 3b held, in particular such that in the direction of the front side 3b showing a thermoset coating on the thermoplastic (thermoset) 4 can be done and the thermoplastic (thermoset) 4 thus can be overmoulded on all sides. After encapsulation with thermoset 9 protrude, in particular the 5 it can be seen only the ends of the connection means 6a and the end of the carrier body used for positioning 3 from the thermoset 9 or the housing formed by this 8th out. Thus, a dense and robust sensor arrangement 1 easily available.

9 shows an embodiment of the invention, in which the connection means 7 the sensor assembly 1 in step D) also with thermoset 9 were at least partially sprayed. This allows improved strain relief and increased resistance to breakage at connection points with connection means 6a of the magnetic field sensor 6 be guaranteed.

LIST OF REFERENCE NUMBERS

1

sensor assembly

1'

unhoused sensor assembly

2

Vorumspritzling

3

support body

3a, b

front sides

4

Thermoplastic (thermoset)

4a

structure 4

5

admission

6

magnetic field sensor

6a

connection means 6

6b

Hall plate

6c

peripherals

6d

capacitor

7

connection means 1

8th

casing

9

thermoset

9a

fastener

d

diameter

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007018238 A1 [0002]

Claims (15)

Method for producing a sensor assembly ( 1 . 1' ), in particular a speed sensor assembly, with a magnetic field sensor ( 6 ) and a flux guide element cooperating therewith ( 3 ), characterized by the steps: A) providing the flux-conducting element in the form of a magnetically flux-conductive, in particular pin-shaped, carrier body ( 3 ); B) forming a pre-molded part ( 2 ) with a recording ( 5 ) for the magnetic field sensor ( 6 ) adjacent to the carrier body ( 3 ) by positioning and at least partially encapsulating the carrier body ( 3 ) with a thermoplastic or thermoset ( 4 ); C) arranging the magnetic field sensor ( 6 ) in the recording ( 5 ). Method according to Claim 1, characterized by the further step: D) Positioning of the carrier body ( 3 ) and at least partially encapsulating the magnetic field sensor ( 6 ) and the pre-injection ( 2 ) with a thermoset ( 9 ). Method according to claim 1, characterized in that the receptacle ( 5 ) adjacent to an end face ( 3a ) of the carrier body ( 3 ) is formed. Method according to one of the preceding claims, characterized in that the magnetic field sensor ( 6 ) after arrangement in the receptacle ( 5 ) on the carrier body ( 3 ), in particular on a front side ( 3a ) of the same. Method according to one of the preceding claims, characterized in that Ankontaktiermittel ( 6a ) of the magnetic field sensor ( 6 ) after arranging the magnetic field sensor ( 6 ) in the recording ( 5 ) to Ankontaktiermittel ( 7 ) of the sensor assembly ( 1 ) are contacted. Method according to one of the preceding claims, characterized in that Ankontaktiermittel ( 7 ) of the sensor assembly ( 1 ) and / or the magnetic field sensor ( 6 ) in step B) and / or in step D) are at least partially encapsulated with. Method according to one of the preceding claims, characterized in that the magnetic field sensor ( 6 ) at least one Hall element ( 6b ), in particular a differential Hall sensor. Method according to one of the preceding claims, characterized in that the carrier body ( 3 ) during step B) and / or step D) at a non-sprayed end ( 3b ) is held. Sensor assembly ( 1 . 1' ), in particular a speed sensor module, with at least one magnetic field sensor ( 6 ), characterized in that the sensor assembly ( 1 . 1' ) a particular pin-shaped carrier body ( 3 ), on which a thermoplastic or thermoset ( 4 ) by means of which a receptacle ( 5 ) for the magnetic field sensor ( 6 ) adjacent to the carrier body ( 3 ) is formed, wherein the carrier body ( 3 ) flux-conducting with the magnetic field sensor ( 6 ) cooperates. Sensor assembly ( 1 . 1' ) according to claim 9, characterized in that the magnetic field sensor ( 6 ) on a front side ( 3a ) of the carrier body ( 3 ) is arranged. Sensor assembly ( 1 ) according to one of claims 9 or 10, characterized in that the magnetic field sensor ( 6 ) as well as the molded thermoplastic or thermoset ( 4 ) and / or the carrier body ( 3 ) at least partially with a thermoset ( 9 ) is / are encapsulated, in particular to form a housing ( 8th ). Sensor assembly ( 1 . 1' ) according to any one of claims 9 to 11, characterized in that the magnetic field sensor ( 6 ) is a differential Hall sensor. Sensor assembly ( 1 . 1' ) according to claim 10, characterized in that a plate-shaped Hall element ( 6b ), in particular all Hall elements ( 6b ) of the magnetic field sensor ( 6 ) substantially parallel to the end face ( 3a ) of the carrier body ( 3 ). Sensor assembly ( 1 . 1' ) according to claim 12 and 13, characterized in that the diameter of the carrier body ( 3 ) is selected such that the diameter is at least as large as the distance between two Hall elements ( 6b ) of the differential sensor ( 6 ) added to the positioning tolerance of the carrier body ( 3 ) on the differential sensor ( 6 ). Sensor assembly ( 1 . 1' ) according to one of claims 9 to 14, characterized in that Ankontaktiermittel ( 6a ) of the magnetic field sensor ( 6 ) and / or the sensor assembly ( 1 . 1' ) of the molded thermoplastic or thermoset ( 4 ) and / or the overmoulded thermoset ( 9 ) are at least partially encapsulated.

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