Insert molded electrical contact

A sensor arrangement has a sensor element. A contact element is in electrical contact on the one hand with the sensor element and on the other with contact pins. The contact element is insert moulded with a plastic body. Affixing positions to which the contact element has been affixed, and on which the contact element is exposed respectively have one collar made of plastic material which runs around the exposed areas of the contact element. A sensor arrangement results for which the cost of manufacture is lower than that of the prior art, while the same security against unwanted electrostatic discharging or against the formation of an unwanted short circuit remains.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase application of PCT International Application No. PCT/DE2008/000189, filed Feb. 2, 2008, which claims priority to German Patent Application No. DE 10 2007 014 279.1, filed Mar. 19, 2007, the contents of such applications being incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a sensor arrangement.

2. Description of the Related Art

Sensor arrangements are used in particular in the automobile industry. The installation site of such sensor arrangements is in particular a gearbox or engine compartment of a motor vehicle. The sensor elements of a sensor arrangement of this type are used for example to determine an engine speed or assembly path. The sensor elements are electrically contacted to external read-out or control devices via the contact pins. Contact elements are here surrounded by a plastic body.

SUMMARY OF THE INVENTION

An object of the present invention is to further develop a sensor arrangement of the type described in the introduction in such a manner that the cost of manufacturing it is reduced while maintaining the same level of security against unwanted electrostatic discharge, or against the formation of an unwanted short circuit.

According to aspects of the invention, it has been recognised that no dual-stage injection method for surrounding the contact element with the plastic body is necessary when collars made of synthetic material are provided which run around the affixing positions. As a result, the distance between a surface of the plastic body which is adjacent to the affixing position on the one hand and an exposed area of the contact element on said affixing position on the other is enlarged to such a size that during the mounting of the sensor arrangement or the remaining motor vehicle, and during the use of the motor vehicle, neither an electric discharge nor a short circuit can occur. In particular, due to the collar, a distance between the exposed areas of adjacent affixing positions is enlarged in such a manner that no short circuits, for example as a result of metal shavings, in particular when the sensor arrangement is used in a gearbox, can occur.

An embodiment of a collar can be produced at a low cost when for example the collar is also generated when the plastic body is insert moulded.

A lid according to at least one embodiment protects the sensor element. The lid can completely cover the sensor element. Alternatively, it is possible that the lid only covers the sensor element where protection against unwanted electrostatic discharge or a short circuit is required.

The advantages of the method according to aspects of the invention correspond to those which have already been discussed with reference to the sensor arrangement according to aspects of the invention.

A connecting body according to at least one embodiment makes it easier to mount the sensor arrangement. The connecting body also secures the contactability of the contact pins after the connecting body has been loosened if the connecting body is connected to the contact element via the free contact ends of the contact pins.

A connecting body according to one or more aspects of the invention also ensures a correct relative positioning of the contact paths of the contact element which are assigned to the contact pins.

A connection of the connecting body with the contact element via the contact pins also ensures that the connecting body can be removed during the course of manufacturing the sensor arrangement without leading to exposed areas, on which unwanted electrostatic discharges or short circuits may occur.

By means of caulking in accordance with one or more aspects of the invention, the exposed areas of the contact element can be completely closed. As a result, protection against shavings, or a seal against shavings is in particular guaranteed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A sensor arrangement1has a sensor element with the embodiment shown inFIG. 1which is covered by a shaving protection lid2and which is thus not visible. The arrangement of the sensor element of the embodiment shown inFIG. 1corresponds to that of a sensor element3of the further embodiment of a sensor arrangement shown inFIGS. 2 and 3.

In order to connect the signal of the sensor element with an external read-out and control device not shown in greater detail, contact pins4are used. The latter are arranged on one end of the plastic body5of the sensor arrangement1which lies opposite the sensor element. The plastic body5is also known as a sensor dome. The shaving protection lid2which is used to protect the sensor element3is in particular removably connected to the plastic body5, for example by latching with it or by being hot caulked to it. Overall, with the embodiment shown inFIG. 1, five contact pins4which have been drawn out of the plastic body5lie adjacent to each other.

A contact element6, also known as a punch scrap, is in electrical contact with the sensor element on the one hand and the contact pins4on the other. The contact element6is made of a copper alloy. The contact element6forms conducting or contact tracks which are respectively assigned to the contact pins, and which lead from the respective connection points of the sensor element3through to the contact pins4. The contact element6is insert moulded with the plastic body5. Here, a single-stage insert moulding method is used. With this single-stage insert moulding method, the contact element6is retained or held at affixing positions7in an injecting tool. Overall, fourteen affixing positions7of this type face the viewer from the perspective shown inFIG. 1. After the insert moulding, there is therefore no other injected plastic on the affixing positions7; the affixing positions7are therefore exposed.

Around the areas of the affixing positions7which are bare of the plastic material following the insert moulding, the affixing positions7respectively comprise one circumferential collar8which is made of the injected plastic material. Depending on the form of the retaining elements of the injecting tool, the collar8is here formed with a different diameter and different collar wall thicknesses. With the sensor arrangement1shown inFIG. 1, five collars8with a comparatively large diameter and a comparatively low wall thickness, and nine collars8with a comparatively small diameter and a comparatively large wall thickness are present. The collars8protrude over the remaining plastic body5by approximately 1 mm.

On the collars8with a smaller diameter, the punch scrap6is held, i.e. affixed. With the collars8with a larger collar diameter, the punch scrap6is retained and affixed. For this retention, the punch scrap6has a drill hole.

Since the collars8are produced during the insert moulding of the contact element6with the plastic material which creates the structure of the plastic body5, the collars8are formed as a single piece onto the plastic body5.

The collars8ensure that the areas of the affixing positions7which are bare of the plastic material do not form unwanted contacts with external components or with shavings.

While the sensor arrangement1is being manufactured, the ends of the contact pins4which are later free are connected with each other via a connecting web or connecting body9. The connecting web9is in general exposed, i.e. it is not insert moulded. The connecting web9thus lies completely outside the plastic body5.

The sensor arrangement1shown inFIG. 1is manufactured in the following manner: First, the contact element6is inserted into the injection moulding tool. Due to the fact that the individual conducting tracks are pre-positioned relative to each other via the connecting web9, this insertion is easier than inserting all conducting tracks of the contact element6individually. The contact element6is then insert moulded with the plastic body5. The sensor element3is then inserted into a retainer10(ref.FIG. 2) of the plastic body5, and contact pins11of the sensor element3are connected with the assigned conducting tracks of the contact element6(ref. here alsoFIG. 3). The shaving protection lid2is then placed onto the plastic body5and connected with it.

When insert moulding the contact element6in precisely one injection stage, the collars8are formed at the same time. Ultimately, the connecting web9is cut out of the contact pins4, so that the free ends of the contact pins4are exposed for connection to an external read-out and control device.

Additionally, the formed collars8can be caulked over the affixing positions7, so that the material from the collars8closes the exposed areas of the affixing positions. As a result, further security against unwanted electrical contact from outside is created.

FIGS. 2 and 3show a further embodiment of a sensor arrangement1. Components which correspond to those which are explained above with reference toFIG. 1are assigned the same reference numerals, and are not discussed in detail again.

The sensor arrangement1shown inFIGS. 2 and 3differs from that shown inFIG. 1due to the size and shape of the plastic body or sensor dome5, and due to the arrangement of the affixing positions7and the design of their collars8. With the sensor arrangement1shown inFIGS. 2 and 3, one sleeve in total with a comparatively large diameter is present, and furthermore, nine affixing positions7with collars8with a comparatively small diameter are also present.

It can be seen from the section shown inFIG. 3that on the affixing positions7, the contact element6is held by two opposite sides respectively in the injection tool.

In contrast to the embodiment shown inFIG. 1, the embodiment of the sensor arrangement1shown inFIGS. 2 and 3comprises a total of three contact pins4which are drawn out of the plastic body5.

The manufacture of the sensor arrangement1shown inFIGS. 2 and 3corresponds to that of the sensor arrangement1shown inFIG. 1.