Abstract
A method for producing a device for measuring current intensities, including: providing a resistor arrangement having connection elements and a resistor element arranged therebetween in a current flow direction. The resistor element and the connection elements consist of different electrically conductive materials; forming a contact pin from the material of at least one connection element; positioning a printed circuit board with a conductor track and a passage bore on the resistor arrangement such that the contact pin projects through the passage bore and has on the side of the printed circuit board facing away from the resistor arrangement a protrusion; laterally widening the contact pin in the region of the protrusion by deforming the material such that the printed circuit board is mechanically fixed to the resistor arrangement; and producing an electrically conductive connection between the contact pin and the conductor track of the printed circuit board.
Claims
1. A method for producing a device for measuring current intensities by a resistor arrangement, wherein the method comprises the following steps: a) providing a resistor arrangement comprising at least two connection elements and at least one resistor element arranged between the connection elements in relation to the direction of the flow of current, wherein the at least one resistor element on the one hand and the connection elements on the other hand consist of different electrically conductive materials, b) forming at least one contact pin from the material of at least one connection element, c) positioning a printed circuit board, which has at least one conductor track and at least one passage bore, on the resistor arrangement in such a way that the at least one contact pin projects through the passage bore and has on the side of the printed circuit board facing away from the resistor arrangement a protrusion beyond the printed circuit board, d) laterally widening the contact pin at least in the region of the protrusion thereof by deforming the material such that the printed circuit board is mechanically fixed to the resistor arrangement, e) producing an electrically conductive connection between the contact pin and at least one conductor track of the printed circuit board.
2. The method according to claim 1, wherein the contact pin is formed in method step b) by an embossing step or by extrusion.
3. The method according to claim 2, wherein a negative form with at least one recess corresponding to the contour of the contact pin is used to shape the contact pin.
4. The method according to claim 1, wherein the contact pin is widened laterally in method step d) by an upsetting process, by embossing, by caulking or by flanging.
5. The method according to claim 1, wherein the lateral widening of the contact pin in method step d) is supported by heating the material by ultrasound or by a laser.
6. The method according to claim 1, wherein the electrically conductive connection is produced in method step e) by laterally widening the contact pin in the region of the protrusion thereof in method step d).
7. The method according to claim 1, wherein the electrically conductive connection is produced in method step e) by virtue of the contact pin being deformed in such a way that it makes contact with the inner surface of the passage bore of the printed circuit board.
8. A device for measuring current intensities comprising a resistor arrangement and a printed circuit board mechanically and electrically connected to the resistor arrangement, wherein the resistor arrangement comprises at least two connection elements and at least one resistor element arranged between the connection elements, wherein the at least one resistor element on the one hand and the connection elements on the other hand consist of different electrically conductive materials, and wherein the printed circuit board has at least one conductor track and at least one passage bore, wherein the resistor arrangement has at least one contact pin monolithically connected to one of the connection elements and formed out of the material of the connection element, by way of which contact pin the resistor arrangement is connected to the printed circuit board by virtue of the contact pin extending through the passage bore of the printed circuit board and having on the side of the printed circuit board facing away from the resistor arrangement a lateral widening, by way of which the printed circuit board is mechanically fixed to the resistor arrangement.
9. The device according to claim 8, wherein the at least one contact pin is in electrical contact with at least one conductor track of the printed circuit board by the lateral widening of said contact pin.
10. The device according to claim 8, wherein the at least one contact pin is in electrical contact with the inner surface of the passage bore of the printed circuit board.
11. The device according to claim 8, wherein the at least one contact pin has a projection, on which the printed circuit board rests in such a way that the printed circuit board is spaced apart from the connection element.
12. The device according to claim 8, wherein the surface of the at least one contact pin has a metallic coating, in particular a coating containing tin, silver or nickel.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Exemplary embodiments of the invention are explained in more detail on the basis of the schematic drawings, in which:
[0041] FIG. 1 shows an oblique view of a resistor arrangement,
[0042] FIG. 2 shows a side view of a resistor arrangement,
[0043] FIG. 3 shows a resistor arrangement upon conclusion of method step b),
[0044] FIG. 4 shows a resistor arrangement with formed contact pins,
[0045] FIG. 5 shows a resistor arrangement with printed circuit board positioned thereon,
[0046] FIG. 6 shows a resistor arrangement with printed circuit board fixed thereto,
[0047] FIG. 7 shows a device with contact pins with projection,
[0048] FIG. 8 shows a device with hollow contact pins.
[0049] Parts corresponding to one another are provided with the same reference symbols throughout the figures.
DETAILED DESCRIPTION
[0050] FIG. 1 shows an oblique view of a resistor arrangement 2 without a contact pin. The resistor arrangement 2 has two terminal connection elements 3 and a resistor element 4, which is positioned between the two connection elements 3. The connection elements 3 and the resistor element 4 each have a plate-like shape. The thickness of the resistor element 4 is somewhat lower than the thickness of the two connection elements 3. The resistor arrangement 2 can be connected to a circuit at the two connection elements 3. For this purpose, the two connection elements 3 can have connecting devices (not illustrated), for example bores. Said connecting devices are each mounted in the region of the connection elements 3 that is remote from the resistor element 4. The resistor element 4 is located between the connection elements 3 in relation to the direction of current flow. When current flows, a voltage drops across the resistor element 4, based on which the intensity of the current flowing through the resistor arrangement 2 can be determined.
[0051] FIG. 2 shows a side view of a resistor arrangement 2 according to FIG. 1. A resistor arrangement 2 as illustrated in FIGS. 1 and 2 can be produced in a known way by longitudinal seam-welding three ribbons to form a composite material and subsequently cutting the welded composite material to length.
[0052] FIG. 3 shows the resistor arrangement 2 according to FIGS. 1 and 2 upon completion of method step b). A negative form 12 with two recesses 13 has been positioned on the top side of the resistor arrangement 2. Two stamps 11 have been pressed into the material of the two connection elements 3 on the underside of the resistor arrangement 2. The stamps 11 are positioned so that they lie opposite the recesses 13 of the negative shape 12. By pressing in the stamps 11, material of the connection elements 3 has been dislodged perpendicularly to the surface of the connection elements 3 and displaced into the recesses 13 of the negative form 12. In this way, two material projections have been formed, which form contact pins 5. The contact pins 5 are embodied as solid in the case illustrated.
[0053] FIG. 4 shows the resistor arrangement 2 with two formed contact pins 5 according to method step b). The stamps 11 and the negative form 12 have been removed. To facilitate the removal of stamps 11 and negative form 12, the stamps 11 and the recesses 13 in the negative form 12 can each have a contour with bevels for demolding. Accordingly, the formed contact pins 5 can likewise have a contour with bevels. The angle that the bevels for demolding enclose with the normals on the surface of the connection elements 3 is typically approximately 2°. On account of said low deviation from the normals, the bevels are not explicitly illustrated in the figures. The height of the contact pins 5 is denoted by the symbol H. The contact pins 5 are provided to tap the voltage dropped across the resistor element 4. To minimize distortions in the measured value, the contact pins 5 have been formed from the connection elements 3 in such a way that they are positioned close to the connecting point between the respective connection element 3 and the resistor element 4.
[0054] FIG. 5 shows the resistor arrangement 2 with two formed contact pins 5 and a printed circuit board 8 positioned on the resistor arrangement 2. FIG. 5 therefore illustrates the resistor arrangement 2 and the printed circuit board 8 after method step c). The printed circuit board 8 has two passage bores 9. The printed circuit board 8 has been positioned so that the contact pins 5 project through the passage bores 9. The height H of the contact pins 5 is greater than the thickness T of the printed circuit board 8 such that the contact pins 5 each have on the side of the printed circuit board 8 facing away from the resistor arrangement 2 a protrusion 6 beyond the printed circuit board 8. The clear width of the passage bores 9 is slightly larger than the external dimension of the contact pins 5.
[0055] FIG. 6 shows a device 1 for measuring current intensities with a resistor arrangement 2 and a printed circuit board 8 fixed to the resistor arrangement 2. FIG. 6 shows the device 1 after method step e). The two contact pins 5 of the resistor arrangement 2 have been deformed so that they mechanically fix the printed circuit board 8 to the resistor arrangement 2 and at the same time each establish an electrical contact with each conductor track of the printed circuit board 8. To this end, the contact pins 5 have been laterally widened both in the region of the protrusion 6 thereof beyond the printed circuit board 8 and in the region located within the passage bore 9 of the printed circuit board 8. In the region of the passage bore 9, the lateral widening is limited by the inner wall of the passage bore 9. The contact pins 5 fill the respective passage bore 9 in a form-fitting manner. In the region of the protrusion 6, the deformation is effected to the extent that a respective lateral widening 7 is produced, which extends further than the width of the respective passage bore 9. The contact pins 5 therefore obtain a shape with a T-shaped cross section in the axial direction. As a result, the printed circuit board 8 is fixed in a force-fitting manner to the resistor arrangement 2. At the same time, the lateral widening 7 of each contact pin 5 makes contact with in each case at least one conductor track on the side of the printed circuit board 8 facing away from the resistor arrangement 2. Electrical connections are therefore established between the resistor arrangement 2 and the printed circuit board 8. The conductor tracks are connected to electronic components (not illustrated), by means of which the voltage dropped across the resistor element 4 can be determined.
[0056] FIG. 7 shows a further exemplary embodiment of a device 1 for measuring current intensities with a resistor arrangement 2 and a printed circuit board 8 fixed to the resistor arrangement 2. In the exemplary embodiment illustrated in FIG. 7, the thickness of the resistor element 4 is approximately equal to the thickness of the connection elements 3. The contact pins 5 each have a projection 51, which surrounds the contact pin 5 and on which the printed circuit board 8 rests. For this purpose, the contact pins 5 are designed so that the external dimensions of the contact pins 5 in the subregion of the respective contact pin 5 directly adjoining a connection element 3 is in each case greater than the clear width of the respective passage bore 9 of the printed circuit board 8. The printed circuit board 8 therefore does not rest either directly on the connection elements 3 or on the resistor element 4 but instead has a spacing s from the connection elements 3, from the resistor element 4 and therefore from the entire resistor arrangement 2. The printed circuit board is thus better thermally decoupled from the resistor arrangement. When the contact pins 5 are formed from the material of the respective connection element 3, the height of the respective projection 51 has already been taken into account. The fixing and contact-connection of the printed circuit board 8 by way of the contact pins 5 is effected in a manner analogous to the exemplary embodiment illustrated in FIG. 6 and explained in connection with FIG. 6.
[0057] FIG. 8 shows as a further exemplary embodiment a device 1 for measuring current intensities with a resistor arrangement 2 and a printed circuit board 8 fixed to the resistor arrangement 2, wherein the contact pins 5 are each embodied to be hollow over their entire extent. In order to produce a respective lateral widening 7 to fix the printed circuit board 8, the contact pins 5 have been flanged in the region of the protrusion 6 thereof. The contact pins 5 have a shape similar to that of a hollow rivet. In the exemplary embodiment of the device 1 illustrated in FIG. 8, the printed circuit board 8 rests on the two connection elements 3. As an alternative, it would also be possible to embody the hollow contact pins 5 with a projection 51, similar to the contact pins 5 illustrated in FIG. 7, such that the printed circuit board 8 is spaced apart from the connection elements 3.
[0058] For reasons of better illustrability, the invention has been explained in FIGS. 1 to 8 in an exemplary manner on the basis of resistor arrangements 2 that each comprise only one resistor element 4 and two terminal connection elements 3. It is also possible to apply the method described above to resistor arrangements that have two or more resistor elements 4 and at least one further connection element 3 arranged between two resistor elements 4 in relation to a possible current path. The resistor arrangement can in this case be configured so that the same current flows through at least two resistor elements 4, which makes a redundant current measurement possible, or that different currents flow through at least two resistor elements 4, which makes the measurement of partial currents possible. The method for forming contact pins 5 and for producing a mechanical and electrical connection to a printed circuit board 8 explained based on the above description, based on FIGS. 1 to 8 and based on the exemplary embodiments can in these cases also be used to form one or more contact pins 5 from the material of a connection element 3 arranged between two resistor elements 4.
LIST OF REFERENCE SIGNS
[0059] 1 Device [0060] 2 Resistor arrangement [0061] 3 Connection element [0062] 4 Resistor element [0063] 5 Contact pin [0064] 51 Projection [0065] 6 Protrusion [0066] 7 Lateral widening [0067] 8 Printed circuit board [0068] 9 Passage bore [0069] 11 Stamp [0070] 12 Negative form [0071] 13 Recess [0072] H Height [0073] T Thickness [0074] S Spacing
