Patent Application
20140144666
This application claims priority to German application number 10 2012 111 491.9 filed on Nov. 27, 2012, the contents of which are hereby incorporated by reference.
The disclosure relates to an electronic device, in particular an inverter, especially a modular inverter. The electronic device comprises housing parts which in an assembled state are electrically connected to one another.
Electronic devices are often accommodated in conductive housing parts and these are connected to a reference potential such as earth potential. This ensures the elimination of risks caused by contact of the housing, arising as a result of electric potentials that are built up inside the housing during operation, being transferred to parts of the housing. In particular in the case of inverters for photovoltaics, dangerous voltages of several hundred volts may occur as a result of a connected solar generator, and so reliable earthing of all the housing parts that could be contacted is required.
It is known to screw the individual housing parts to one another, in order to achieve reliable fixing of the housing parts to one another and at the same time reliable electrical connection between the parts. In this respect it is required specifically in the case of painted or powder-coated housing parts additionally to place under each of the screws a contact plate, which penetrates the coating during screwing in order to ensure the electrical contact between the screw and the housing part. The effort that is involved in assembly is considerable in the case of this connection technique, and so there is a need for the associated costs to be saved by providing other connection techniques.
The document DE 10 2009 008 527 discloses a housing for sensor electronics in which a cover has web-shaped formations, which during assembly of the cover engage in corresponding formations of the housing and achieve mechanical securement of the cover by plastic-elastic deformation. The cover may subsequently be welded or adhesively bonded to the housing.
An electronic device according to the disclosure has a base as a first housing part and a cover as a second housing part. Both housing parts are formed completely or at least partially from conductive material or have a conductive coating and, in an assembled state of the electronic device, are electrically connected to one another by a fastening pair, which comprises a pin with at least three pressure edges and a recess with an opening cross section adapted to the pin. The pin belongs to one of the two housing parts and the recess belongs to the other. In the assembled state, the pin protrudes into the recess in such a way that a holding force between the two housing parts is exerted between the pressure edges of the pin and the walls of the recess.
In another configuration of the electronic device, the pin is a component part of the cover and is, in one embodiment, formed together with the cover as a one-piece housing part. Correspondingly, the recess may be formed together with the base as a one-piece housing part. Alternatively, however, the pin may likewise be a component part of the base and be formed with it as a one-piece housing part, with the recess as part of the cover. It is advantageous in one embodiment to produce the base and/or the cover of the electronic device by means of a diecasting process, in particular an aluminium diecasting process. In this way, it is conceivable in particular to produce the housing parts and the fastening elements in one step, without any further working being required.
In an embodiment according to the disclosure, the base and the cover are provided with an adhesive seal, in particular a silicone seal, in order to form together a sealed housing of the electronic device. It is optionally conceivable to additionally provide a connection plate, which is mounted between the base and the cover and is connected to the base and the cover by way of an adhesive seal. In an assembled state, the electronic device is in this case held together both by the holding force of the fastening pair and by the adhesive force of the adhesive seal.
The pressure edges of the pin in combination with the walls of the recess establish a reliable electrical connection between the two housing parts. A configuration that is advantageous in one embodiment is one in which the pin has a triangular cross section, and consequently precisely three pressure edges, even though for example cross-sectional forms with four, five or more pressure edges are not ruled out. The recess is formed in an opening cross section that is adapted to the assigned pin. The inner walls of the recess are formed in this case such that the distance between the inner wall regions, which in the assembled state are in contact with the pressure edges of the pin, have a slightly smaller inner distance from one another than the outer distance between the corresponding regions of the pressure edges of the pin. In this way, a high pressing force of the pressure edges on the inner walls of the recess is exerted in the assembled state, and at the same time canting of the pin on insertion into the recess is avoided. A sufficiently high pressing force of the pressure edges on the inner walls of the recess leads to local cold welding of the components, and consequently to a particularly reliable electrical and mechanical connection between the housing parts. This cold welding effect can be enhanced by suitable treatment of the surfaces of the pin and/or the recess. The recess may advantageously be round. Furthermore, the pin or the recess may be provided with surface structures such as steps, channels, undercuts or roughenings, which improve the electrical and mechanical properties of the connection between the housing parts after they have been joined together and for example perform an engaging function.
In one embodiment, the pin is provided with a conical form, in which the cross section of the pin decreases from its root to its tip continuously or in steps. In one embodiment, the angle of inclination of the conical form of the pin and the angle of inclination of the inner walls of the recess are in this case made to match one another, and so, after insertion of the pin into the recess, a uniform pressing force between the pressure edges of the pin and the inner wall of the recess is achieved over the length of the pressure edges.
Even if it is conceivable to connect the cover and the base to one another additionally by screws, in an embodiment according to the disclosure of the electronic device the cover and the base are electrically and mechanically connected to one another in the assembled state by a screw-less connection. In this way, the assembly of the electronic device can be performed in a particularly simple and low-cost manner.
The electronic device may advantageously be an inverter, in particular an inverter for photovoltaics. The assembly technique can bring its special advantages to bear in particular when it is used inside a modular inverter, since these inverters have a small structural form and a low weight and are produced in large numbers.
Advantageous developments of the disclosure are provided by the patent claims, the description and the drawings. The advantages mentioned in the present description of features or of combinations of multiple features are only examples and may come into effect alternatively or cumulatively without the advantages of the embodiments according to the disclosure necessarily having to be achieved. The embodiments that are disclosed in the description serve a person skilled in the art as options for the implementation of the disclosure, though the disclosure is not restricted to these example embodiments. A person skilled in the art will regard these example embodiments as suggestions for deriving other refinements of the disclosure—including with variants of the implementation of the features thereof that are not specifically disclosed here—on the basis of the actual need of the individual case.
The features mentioned in the patent claims and the description should be understood with respect to their number such that precisely this number or a greater number than the number mentioned is present, without explicit use of the adverb “at least” being required. If, on the other hand, only the precise number of a feature is to be specified, the adjective “precisely” is used before the respective feature. These features may be supplemented by other features or be the only features of the respective product.
The disclosure is explained in more detail and described below on the basis of example embodiments with reference to the appended drawings.
The disclosure addresses the problem of providing an electronic device in which the cover and the base can be assembled in a particularly simple and low-cost manner in such a way that, after assembly, there is an electrical connection permanently between them.
It is conceivable to distribute any number of pins over the housing part, in this case the cover 2. In one embodiment, however, at least two pins are provided, to achieve a reliable electrical connection and a reliable holding force of the cover after assembly.
In a one-piece version, the pins 7 are configured as part of the cover 2 and are produced together with the cover while it is being formed. Although it is conceivable to insert the pins 7 into recesses of the cover 2 only after production of the cover 2, as independent components, this would mean that production involves increased effort due to an additional assembly step. The cover 2 could be produced for example in an aluminium diecasting process, whereby the pins can be produced together with the cover without any additional effort and without subsequent working. It goes without saying, however, that subsequent working of the pins may be provided, for example in order to improve further the electrical properties or the holding properties of the pin inserted into a recess.
As an alternative to the described production of the cover and the base by means of a diecasting process, in particular an aluminium diecasting process, a plastics injection-moulding process may also be used. After they have been produced, the parts of plastic are partially—for example on the surfaces facing the inside of the device—or completely coated in an electrically conducting manner, for example by painting or vapour deposition. They can consequently be regarded in the sense of the present disclosure as produced from conductive material. The electrically conducting connection between the parts is performed in the same way as described further above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2012 111 491.9 | Nov 2012 | DE | national |
