Method for manufacturing an apparatus for measuring current intensity and apparatus for measuring current intensity

Abstract

To provide a device for measuring current intensity and a manufacturing method therefor that are simpler and more inexpensive.SOLUTION: A method includes the steps of: providing a resistance assembly 2 comprising two connection elements 3 and one resistance element 4 disposed between the connection elements; molding one contact element 5 having an edge face apart from the resistance assembly and a hollow space 53 opening on there from material of one connection element or material of the resistance element; providing a conductor board 8 comprising one open hole having an inner surface 91 on which a conductive material 92 is provided; positioning the conductor board on the resistance assembly so that the contact element protrudes in the open hole; and expanding the contact element in a radial direction using expansion means 14. The expansion means is inserted into the hollow space of the contact element, which creates conductive connection between the contact element and the conductive material on the inner surface of the open hole.SELECTED DRAWING: Figure 6

Description

[[Technical Field]]

[0001] The present invention relates to a method of manufacturing an apparatus for measuring current intensity, and to such an apparatus. [[Background Art]]

[0002] For current measurement in electronic circuits, a measuring resistor connected in series with the component to be monitored is used. In this case, the current intensity is determined from the voltage dropped across the measuring resistor, which is referred to as a shunt resistor. Accurate and reliable measurement of current intensity is particularly important, for example, in battery management systems for electric vehicles or hybrid vehicles. A resistor assembly comprising a low-ohmic measuring resistor of about 10 to 50 μOhm and connecting elements for connecting the resistor assembly to an electric circuit can be manufactured from a longitudinally seam-welded composite material. This is known, for example, from Patent Document 1. The composite material is fabricated from three metal strips, wherein the individual metal strips are each connected to each other via a longitudinal seam by electron beam welding or laser welding.

[0003] The voltage dropped across the measuring resistor is tapped off via contact pins or similar elements arranged on both sides of the measuring resistor on the connecting elements. Such contact pins can be soldered, crimped or welded to the connecting elements of the resistor assembly. The voltage is detected and further processed by measuring and evaluation electronics. For this purpose, electronic components that can be arranged on a conductor substrate are provided. In this case, the conductor substrate can be arranged in the immediate vicinity of the resistor assembly.

[0004] Patent Document 2 discloses a resistor assembly having a low-ohmic current measuring resistor. In this resistor assembly, connecting contacts formed by embossing and thread forming on a plate-shaped member used for connecting the resistor assembly to an external electric circuit are provided for tapping off voltage. The connection of the measuring line for voltage measurement to the connecting contacts is effected by means of a cable shoe and a fixing screw.

[0005] Furthermore, Patent Document 3 provides a resistor assembly having two plate-shaped elements and one strip-shaped resistor element for connecting the resistor assembly to an external electrical circuit. One hole is provided in each of the two connecting elements on either side of the resistor element, and one contact pin is inserted into each of these holes. The contact pin is a separate component that needs to be manufactured and added to the resistor assembly for this purpose.

[0006] Conventional devices require the use of additional components to extract the voltage drop across the measuring resistor. This adds extra effort and cost. Furthermore, contact voltages can be generated at the contact points of individual components, potentially distorting the voltage signal. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] European Patent Application Publication No. 0605800 [Patent Document 2] German Patent Application Publication No. 102009031408 Specification [Patent Document 3] U.S. Patent No. 10163553 [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention is based on the problem of providing an improved, in particular simpler and less expensive method for manufacturing an apparatus for measuring electric current intensity, and providing such an apparatus. [Means for solving the problem]

[0009] Book The invention relates to a method for manufacturing an apparatus for measuring current intensity by a resistor assembly, the method being: a) A step of providing a resistor assembly comprising at least two connecting elements that determine the direction of current, and at least one resistive element positioned between the connecting elements in the direction of current, wherein at least one resistive element and the connecting elements are made of different conductive materials. b) A step of forming at least one contact element from the material of at least one connecting element or from the material of a resistive element, wherein the contact element has a longitudinal axis defining an axial direction and a radial direction perpendicular thereto, and the contact element is formed to have an end face away from the resistive assembly and a hollow space opened at the end face of the contact element away from the resistive assembly. c) Providing a conductive substrate having at least one through hole having an inner surface provided with a conductive material, d) The step of positioning the conductor substrate on the resistor assembly such that the conductor substrate has an upper surface that is separated from the resistor assembly and at least one contact element protrudes into the through hole, e) A step of radially expanding a contact element by an expanding means (Aufweitmittel), wherein the expanding means is inserted axially into the hollow space of the contact element, thereby creating a conductive connection between the contact element and a conductive material on the inner surface of the through hole, comprising the steps of 。 [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of a resistor assembly. [Figure 2] This is a side view of the resistor assembly. [Figure 3] This is a partial cross-sectional view of the resistor assembly upon completion of step b) of the method. [Figure 4] This is a partial cross-sectional view of a resistor assembly with a molded contact element. [Figure 5] This is a partial cross-sectional view of a resistor assembly with a conductor substrate positioned. [Figure 6] This is a partial cross-sectional view of the resistor assembly during step e) of the method. [Figure 7]It is a partial cross-sectional view of a resistor assembly with a conductor substrate fixed thereto. [Figure 8] It is a partial cross-sectional view of a resistor assembly with a conductor substrate fixed thereto and a contact element having a stepped portion. [Figure 9] It is a partial cross-sectional view of a resistor assembly with a conductor substrate fixed thereto and a contact element having a conical section. Description of Embodiments

[0011] The measurement of current intensity can also be understood as the measurement of the intensity of a current that may change temporarily. The above-described resistor assembly can be equipped with shunt resistors with resistances of 10 to 50 μOhm as resistive elements. The resistive elements and connecting elements are made of conductive materials. In this case, the specific resistivity of the material of the resistive element is significantly larger than that of the material of the connecting element, typically by a factor of at least 10. On the other hand, the value of the temperature coefficient of resistance of the material of the connecting element is much larger than that of the material of the resistive element, typically by a factor of at least 80. Typically, the temperature coefficient of resistance of the material of the resistive element is ±5·10 -5 While the resistance temperature coefficient is less than 1 / K, the resistance temperature coefficient of the connecting element material is approximately ±4·10. -3 The ratio is 1 / K. The connecting elements of the resistive assembly may consist of copper, preferably a low-alloy copper alloy, aluminum, or preferably a low-alloy aluminum alloy, or may include at least one of these materials. The resistive elements may consist of copper alloys commonly used as resistive alloys.

[0012] The connecting element may be one at the end of the resistor assembly. However, at least one connecting element may also be positioned between two resistors in a possible current path. The resistor assembly can be formed in a planar arrangement. In this case, the connecting element and at least one resistor are formed as plate- or strip-shaped elements and arranged side by side on a plane, preferably in a row. In this case, the thickness of one or more resistors can be arbitrary, however they are usually less than or equal to the thickness of the connecting element.

[0013] A contact element is understood to be a material projection rising from the otherwise undeformed surface of a connecting element or resistive element. The contact element is formed by moving the material of the connecting element or resistive element in a direction substantially perpendicular to the surface of the connecting element or resistive element. The direction of material movement defines an axial direction parallel to the longitudinal axis of the contact element and a radial direction perpendicular thereto. The contact element is formed to have an end face away from the resistive assembly and a hollow space opened at the end face of the contact element away from the resistive assembly. That is, the contact element is at least partially hollow, and the hollow space extends axially into the contact element from the end face of the contact element. The hollow space is radially defined by a surrounding closed wall made of the moved material of the connecting element or resistive element. That is, the contact element has the shape of a sleeve in this region, with at least one side open. Preferably, the hollow space closes on the opposite side in diameter, so that the contact element has a cup-like shape in this region. The height of the contact element is at least 0.5 mm, preferably at least 1 mm.

[0014] The external shape of the contact element can be arbitrary, preferably circular, rectangular, square, or hexagonal. It is preferable that the contact element has an annular cross-section in the hollow space region. The cross-sectional shape and / or size of the contact element may be constant or may change steadily or transiently along the longitudinal axis of the contact element. For example, the contact element may have a slightly conical profile, i.e., a profile in which the interface is slightly inclined with respect to the surface of the connecting or resistive element. Furthermore, the contact element may be molded to have a stepped portion. A stepped portion is understood as a transient, i.e., leaping change in the cross-sectional shape and / or cross-sectional size of the contact element. The stepped portion can be used as an auflage for the conductive substrate.

[0015] A contact element can preferably be used as a voltage tap for measuring the voltage drop across a resistive element, in conjunction with another contact element. If the contact element is molded from the material of the resistive element, it can be used as a voltage tap for measuring the voltage drop across a portion of the resistive element. Alternatively, the contact element can be used to ground the resistive assembly. It is preferable that one or more such contact elements be molded onto all connecting elements of the resistive assembly. In this case, the contact element used for voltage measurement is positioned as close as possible to the resistive element from which the voltage drop is to be detected.

[0016] Within the scope of this invention, a conductive substrate is understood to be a flat, plate-like or strip-like component suitable for conducting electrical signals in a conductive material. A flat component is plate-like or strip-like if two faces of the component that are opposite each other are plan-parallel. The distance between these two faces defines the thickness of the component. A conductive substrate may be, for example, a metal strip or a plate made of a non-conductive material on which conductive paths are provided. Such a plate is known by the term "printed circuit board". A conductive substrate has at least one through-hole having an inner surface provided with conductive material. This includes cases where the conductive substrate is a metal strip or metal plate, thereby inherently providing conductive material on the inner surface of the through-hole. If the conductive substrate is a plate made of a non-conductive material on which conductive paths are provided on its surface, the conductive material can be connected to the inner surface of the through-hole and preferably to the conductive paths located on the side of the conductive substrate away from the resistance assembly. Furthermore, electrical components used for measuring and evaluating electrical signals can be placed on such a conductive substrate. In a conductive substrate, a cavity extending across the entire thickness of the substrate is referred to as a through-hole. Through-holes can have a cylindrical shape, or conical shape.

[0017] The conductive substrate is positioned on the resistor assembly such that at least one contact element protrudes at least within the through-hole. In this case, the conductive substrate is positioned substantially parallel to the resistor assembly, so that it has an upper surface away from the resistor assembly and a lower surface facing the resistor assembly. A distance may exist between the conductive substrate and the resistor assembly. However, it is also possible for the conductive substrate to rest directly on the resistor assembly. The contact element must protrude into the through-hole of the conductive substrate to at least half the thickness of the conductive substrate, preferably at least 70% of the thickness of the conductive substrate.

[0018] Next, the contact element is expanded radially by a suitable expanding means. For this purpose, the expanding means is inserted axially into the hollow space of the contact element from above the conductive substrate. The expanding means is shaped to expand the contact element radially within the region of the hollow space. To this end, the material of the contact element defining the hollow space radially is moved radially outward until it contacts the inner surface of the through-hole in the conductive substrate. In this way, a conductive connection is created between the contact element and the conductive material on the inner surface of the through-hole. The expansion resulting in an increase in the outer dimensions of the contact element is preferably 2% to 15% of the outer dimensions before expansion. Further expansion reduces the thickness of the contact element. A reduction of at least 20% of the original thickness is advantageous. The expanding means may be a suitable tool that is removed again from the hollow space of the contact element after expansion.

[0019] The advantage of the above method is that no additional parts and / or materials are required to create a connection between the resistor assembly and the conductor substrate. Since the contact elements are formed directly from the material of the connecting or resistive elements, there is no need to separately mount the contact elements to the resistor assembly or conductor substrate. This eliminates the necessary work steps and materials, such as solder. Multiple contact elements can be formed simultaneously.

[0020] Monolithic connections between contact elements and connecting elements, or between contact elements and resistive elements, avoid undesirable contact voltages that could distort measurements.

[0021] A particularly advantageous aspect of the proposed method is the radial expansion of the contact element by a suitable expanding means. Since the expanding means is inserted into the hollow space of the contact element, the connection between the contact element and the conductive substrate is made substantially within the region of the through-hole. This eliminates the need for the contact element to protrude onto the conductive substrate, i.e., to have a projection on the upper surface of the conductive substrate. Therefore, to form the contact element, only slight deformation of the material of the connecting or resistive element is required. The required force is minimal. This is advantageous in terms of tool life and process speed. The proposed method is particularly advantageous when one or more contact elements need to be formed from a resistive element. The material of the resistive element is usually more difficult to deform than the material of the connecting element. The process becomes simpler the less deformation is required.

[0022] The expansion means may be an object that remains permanently within the hollow space of the contact element. Such an object may be, for example, a plug or a rivet. Such an object creates a particularly reliable and permanent contact between the contact element and the inner surface of the through-hole in the conductive substrate.

[0023] When a resistor assembly is manufactured by cutting from a band-shaped composite material that has been longitudinally seam-welded, it is preferable that the contact elements be formed simultaneously with the cutting of the composite material. That is, in this case, steps a) and b) of the method are performed simultaneously. Therefore, there is no need for a separate and additional work process to form the contact elements. Thus, this method is faster and less expensive than when the contact elements are formed only after the composite material has been cut. Furthermore, high positional accuracy of the contact elements is achieved in this way.

[0024] Within the scope of one embodiment of the present invention, the expanding means may be formed such that the contact element is expanded by inserting the expanding means. That is, the contact element is already radially expanded during the insertion of the expanding means into the hollow space. For this purpose, the expanding means has at least a partially conical outer contour. This outer contour causes radial movement of the material of the contact element when the expanding means is inserted into the hollow space. This enables a shorter processing time.

[0025] In an alternative embodiment of the present invention, the expanding means may be formed such that the contact element is expanded after the expanding means is inserted. That is, the contact element is expanded radially only after the expanding means is substantially inserted into the hollow space. For this purpose, the expanding means has a section with an outer diameter smaller than the inner diameter of the hollow space. In this case, the insertion of this section of the expanding means into the hollow space is performed with little resistance and therefore without unintentional deformation of the contact element. After the insertion of the expanding means, the contact element is expanded radially by a suitable mechanism. If the expanding means is a tool, this can be done, for example, by expanding the tool, by eccentrically rotating the tool, or by electromagnetic force.

[0026] Within the scope of a preferred embodiment of the present invention, the expansion in step e) can simultaneously create a force-coupled connection between the inner surface of the through-hole in the conductor substrate and the contact element. For this purpose, the expansion of the contact element is carried out to such an extent that the material is pressed firmly against the inner surface of the through-hole in the conductor substrate, thereby forming a press fit. In this case, the thickness of the contact element is preferably reduced by at least 40%. By forming a press fit, it is possible to avoid using any other means for mechanically fixing the conductor substrate onto the resistor assembly.

[0027] Within the scope of a particular embodiment of this invention, the expansion in step e) can also simultaneously create a shape-coupled connection between the inner surface of the through-hole in the conductive substrate and the contact element. For example, the through-hole in the conductive substrate may have a conical shape and may be formed such that its inner diameter expands from the bottom surface to the top surface of the conductive substrate. When an expanding means having a fitted conical outer contour is used, the expansion of the contact element results in a shape-coupled connection. Such a connection is a particularly reliable type of connection.

[0028] Within the scope of a preferred embodiment of the present invention, the contact element may have a height selected such that, after positioning the conductor substrate, the end face of the contact element away from the resistance assembly is either within the through-hole of the conductor substrate or terminates flush with the top surface of the conductor substrate. In this case, the height indicates the extension of the contact element measured axially from the undeformed surface of the connecting or resistive element. That is, the height is dimensional such that the penetration depth of the contact element into the through-hole of the conductor substrate is as close as possible to the thickness of the conductor substrate. In other words, in this embodiment, the contact element does not have any protrusions above the top surface of the conductor substrate. Contact elements of such small height can be molded to a particular advantage. Within the scope of a special form of this embodiment of the present invention, the penetration depth of the contact element into the through-hole of the conductor substrate may be 80-100% of the thickness of the conductor substrate. This is the optimal balance between the effort required during the molding of the contact element and the quality of the contact between the contact element and the conductor substrate.

[0029] Within the scope of another embodiment of the present invention, the shaping of the contact element in step b) can be carried out by an embossing step or fluid press forming. Embossing and fluid press forming are particularly suitable for shaping a contact element that extends substantially perpendicular to the surface of the connecting or resistive element and is monolithically connected to the material of the connecting or resistive element. In this case, the shaping of the material is carried out using a punch and a suitable negative die.

[0030] Within the scope of a particular embodiment of this invention, a negative mold can be used to shape a contact element, having at least one cavity corresponding to the outer contour of the contact element and at least one internal tool positioned in the cavity for shaping the hollow space, during step b) the internal tool is moved relative to the cavity in the direction of the longitudinal axis of the contact element. This proves to be a particularly advantageous procedure from a deformation molding technical standpoint, thereby enabling the production of contact elements with greater height.

[0031] Within the scope of another specific embodiment of the present invention, the expansion of the contact element in step e) can be assisted by heating the contact element material with ultrasound or a laser. The contact element material hardens as a result of the deformation in step b). This hinders the deformation in the subsequent step e). The contact element material can be heated by heat input with a laser or ultrasound until it is at least partially softened, i.e., becomes pliable. In this case, deformation in step e) becomes easier.

[0032] Other technical features and advantages of the method according to the present invention are explicitly referenced in the following description of the apparatus for measuring current intensity, as well as in the figures and their descriptions.

[0033] Another aspect of the present invention relates to an apparatus for measuring current intensity. This can also be interpreted as measuring the intensity of a current that may change temporarily. The apparatus comprises a resistor assembly and a conductive substrate mechanically and electrically connected to the resistor assembly. The resistor assembly comprises at least two connecting elements defining the direction of current and at least one resistive element positioned between the connecting elements in the direction of current, wherein the at least one resistive element and the connecting elements are made of different conductive materials. The conductive substrate has at least one through-hole having an inner surface provided with a conductive material. The resistor assembly comprises at least one contact element having a longitudinal axis, monolithically connected to one of the connecting elements and made from the material of the connecting element, or monolithically connected to a resistive element and made from the material of the resistive element. The contact element conductively and mechanically connects the resistor assembly to the conductive substrate by at least the contact element protruding into the through-hole of the conductive substrate and being forcefully connected to the conductive material on the inner surface of the through-hole. For this purpose, the contact element has an end face away from the resistor assembly and a hollow space opened at the end face of the contact element away from the resistor assembly. The contact element has a conical contour at the transition from its end face to the hollow space.

[0034] With regard to the terminology used to describe the apparatus, the explanation of the method for manufacturing the apparatus for measuring current intensity and the explanation of the above-mentioned terms related thereto are explicitly referenced.

[0035] A special advantage of the above apparatus is that the monolithic connection between the contact element and the connecting or resistive element avoids undesirable contact voltages that could distort measurements. Furthermore, the apparatus can be manufactured inexpensively and with high precision because the contact element is formed directly from the material of the connecting or resistive element. A particularly advantageous embodiment of the above apparatus is a force-coupled connection between a conductive substrate and a resistive assembly. This connection is created by a contact element that is brought into electrical and mechanical contact with the inner surface of a through-hole in the conductive substrate by an expansion process. To perform this expansion process, the contact element has an end face that is separated from the resistive assembly and a hollow space opened at the end face of the contact element separated from the resistive assembly. The contact element has a conical contour at the transition from its end face to the hollow space. This conical contour is a result of the expansion process and can be used to more easily insert the expansion means into the hollow space of the contact element.

[0036] Within the scope of one embodiment of the present invention, the contact element may have a height selected such that the end face of the contact element away from the resistive assembly is within the through-hole of the conductive substrate or terminates flush with the upper surface of the conductive substrate. In this case, the height indicates the extension of the contact element in the direction of its longitudinal axis, measured from the undeformed surface of the connecting or resistive element. That is, the height is dimensional such that the penetration depth of the contact element into the through-hole of the conductive substrate is as close as possible to the thickness of the conductive substrate. In other words, the contact element does not have any protrusions above the upper surface of the conductive substrate. This small-height contact element can be molded to a particular advantage. Within the scope of a special embodiment of this embodiment of the present invention, the penetration depth of the contact element into the through-hole of the conductive substrate may be 80-100% of the thickness of the conductive substrate. This is an optimal balance between the effort required during the molding of the contact element and the quality of the contact between the contact element and the conductive substrate.

[0037] Within the scope of alternative embodiments of the present invention, the contact element may have a projection on the conductive substrate on the side of the conductive substrate away from the resistor assembly, and in the region of this projection, it may be laterally widened, preferably conically, to secure the conductive substrate. By laterally widening, preferably conically, the contact element in the region of this projection on the conductive substrate, the conductive substrate is shape-coupled to be secured in at least one direction, i.e., in the axial direction of the contact element, i.e., in the direction of the connecting element of the resistor assembly. The contact element may be laterally widened by other modifications other than conically widening. Examples include crimping with a spherical, cylindrical, or ball-shaped tool, flanged, partially bent, and widened.

[0038] Within the scope of a particular embodiment of this alternative embodiment of the present invention, the contact element comprises a section having a conical outer contour between the connecting element and the conductive substrate. In this case, the conical section is selected such that the cross-sectional area of ​​the contact element expands toward the connecting element. The section with the conical contour is directly adjacent to the conductive substrate. The conical outer contour causes the cross-sectional area of ​​the contact element to expand steadily, until it is at least larger than the cross-sectional area of ​​the through-hole in the conductive substrate. Thus, along with the conical expansion of the contact element in the region of the protrusion, shape-coupled and force-coupled fixing of the conductive substrate can be achieved in the axial direction of the contact element and in the direction perpendicular thereto. The conductive substrate is clamped by the contact element in a double conical manner. This embodiment of the present invention is particularly resistant to mechanical loads such as vibration.

[0039] Within the scope of another advantageous embodiment of the device, at least one contact element may have a stepped portion on which the conductor substrate rests, such that the conductor substrate is separated from the connecting element, and therefore from the resistor assembly. The distance between the conductor substrate and the resistor assembly better thermally isolates the conductor substrate from the resistor assembly. In this case, the heat generated when current flows through the resistor element is not directly transferred from the resistor or connecting element to the conductor substrate, but is forced to flow through the contact element. The contact element exhibits high thermal resistance due to its relatively small cross-section. Therefore, the heat flow from the resistor assembly to the conductor substrate is reduced, and the conductor substrate remains at a lower temperature level than when the conductor substrate rests directly on the connecting element. This embodiment is particularly advantageous when the thickness of the resistor element is not less than the thickness of each of the connecting elements.

[0040] Furthermore, within the scope of one particularly advantageous embodiment of the device, the first contact element may have a conical section between the connecting element and the conductor substrate, while the second contact element may have a stepped section between the connecting element and the conductor substrate on which the conductor substrate rests. In particular, in this case, the two contact elements may each have a projection on the conductor substrate on the side of the conductor substrate away from the resistor assembly, and the region of the projection may be extended laterally. A special advantage of combining contact elements of different shapes and functions in this way is that, when loads due to vibration and temperature changes are superimposed, the first contact element provides lateral fixation of the conductor substrate, while the second contact element allows for fixation of the conductor substrate perpendicular to the conductor substrate without additionally restricting the lateral degrees of freedom of motion. Thus, the different expansion of the conductor substrate and the resistor assembly reduces the stress that may occur when the temperature changes. Therefore, the device is particularly robust.

[0041] In an advantageous embodiment of the present invention, the surface of at least one contact element may have a metallic coating, particularly a tin-containing, silver-containing, or nickel-containing coating. Such a coating prevents corrosion and thus ensures high-quality electrical contact between the contact element and the conductive material on the inner surface of the through-hole throughout the life of the device. In this case, the coating may be applied before the formation of the contact element in step b), or the contact element may be coated in a separate step between steps b) and c).

[0042] Regarding other technical features and advantages of the apparatus according to the present invention, the above-mentioned description of the method according to the present invention, as well as the figures and their descriptions, are expressly referenced.

[0043] Embodiments of the present invention will be described in detail based on schematic drawings.

[0044] Corresponding parts are given the same reference numeral in all the figures.

[0045] Figure 1 shows a perspective view of a resistor assembly 2 without contact elements. The resistor assembly 2 has two terminal connectors 3, 3' and one resistor 4 positioned between the two connectors 3, 3'. The connectors 3, 3' and the resistor 4 are each plate-shaped. The thickness of the resistor 4 is somewhat less than the thickness of each of the two connectors 3, 3'. The resistor assembly 2 can be connected to an electrical circuit by the two connectors 3, 3'. For this purpose, the two connectors 3, 3' may have connecting devices, such as holes, which are not shown. These connecting devices are each located in a region of the connectors 3, 3' away from the resistor 4. The resistor 4 is positioned between the connectors 3, 3' in the direction of current flow. When current flows, a voltage drops across the resistor 4, and this voltage can be used to detect the current strength flowing through the resistor assembly 2.

[0046] Figure 2 shows a side view of the resistor assembly 2 according to Figure 1. The resistor assembly 2 shown in Figures 1 and 2 can be fabricated, as is known, by longitudinally seam welding three strip-shaped bodies to form a composite material, and then cutting the welded composite material.

[0047] Figure 3 shows an enlarged partial cross-sectional view of the resistor assembly 2 according to Figures 1 and 2 at the completion of step b) of the method. A negative mold 12 having a cavity 121 and an internal tool 122 positioned within the cavity 121 is positioned on the upper surface of the connector element 3. Below the connector element 3, a punch 11 penetrates the material of the connector element 3, as indicated by the upward arrow. The punch 11 is positioned so that it is located opposite the cavity 121 of the negative mold 12. By penetrating with the punch 11, the material of the connector element 3 is deformed substantially perpendicular to the surface of the connector element 3 and transferred into the open space of the negative mold 12 defined by the cavity 121 and the internal tool 122. In this way, the material protrusions forming the contact element 5 are formed. The internal tool 122 results in the contact element 5 having a hollow space that is open on one side after the removal of the internal tool 122.

[0048] Figure 4 shows an enlarged partial cross-sectional view of the resistor assembly 2 in which the contact element 5 has been formed in method step b). The punch 11 and negative die 12 have been removed. To facilitate the removal of the punch 11 and negative die 12, the punch 11, the cavity 121, and the internal tool 122 in the negative die 12 can each have a beveled contour for demolding. Accordingly, the formed contact element 5 can also have a beveled contour. The angle that the demolding bevel makes with the normal to the surface of the contact element 3 is typically about 2°. Because the deviation from the normal is small, the bevel is not clearly shown in the figure.

[0049] The contact element 5 has a longitudinal axis A oriented perpendicular to the surface of the connecting element 3. Furthermore, the contact element 5 has an end face 52 that is separated from the connecting element 3 and therefore from the resistor assembly 2. The hollow space 53 extends from this end face 52 along the longitudinal axis A of the contact element 5. In the illustrated example, this hollow space 53 extends to about the undeformable surface of the connecting element 3. However, for manufacturing reasons, it may be advantageous to mold the contact element 5 such that the hollow space 53 extends relatively little into the contact element 5, or alternatively, that the hollow space 53 reaches into the material of the connecting element 3. Due to the hollow space 53, the contact element 5 has the shape of a sleeve with one side closed and the other side open. The height of the contact element 5 is indicated by the symbol H. The height H is measured from the undeformable surface of the connecting element 3 to the end face 52 of the contact element 5.

[0050] The contact element 5 is provided to extract the voltage drop across the resistive element 4. To minimize distortion of the measured values, the contact element 5 is molded from the connecting element 3 so that it is positioned close to the connection point between the connecting element 3 and the resistive element 4.

[0051] Figure 5 shows an enlarged partial cross-sectional view of the resistor assembly 2 according to Figure 4, with a conductor substrate 8 of thickness D added and positioned on the resistor assembly 2. Thus, Figure 5 shows the resistor assembly 2 and conductor substrate 8 according to method step d). The conductor substrate 8 has a through hole 9. The inner surface 91 of the through hole 9 of the conductor substrate 8 is provided with a conductive material 92, which is not shown in detail for reasons of clarity. The conductor substrate 8 is positioned such that the contact element 5 protrudes into the through hole 9 to an intrusion depth T. In the illustrated example, the intrusion depth T is somewhat less than the thickness D of the conductor substrate 8, so that the end face 52 of the contact element 5 does not terminate flush with the upper surface 81 of the conductor substrate 8, but is still inside the through hole 9. The intrusion depth T is about 90% of the thickness D of the conductor substrate 8. The inner width of the through hole 9 is slightly larger than the outer dimensions of the contact element 5. In the illustrated embodiment, the conductor substrate 8 does not rest directly on the connecting element 3, which can be achieved, for example, by a spacer not shown. A large distance between the conductive substrate 8 and the resistive element 4 is advantageous because it allows for rapid dissipation of heat generated in the resistive element. Electronic components that may be present on the conductive substrate 8 are not shown for clarity.

[0052] Figure 6 is an enlarged partial cross-sectional view of the resistance assembly 2 during step e) of the method. An expanding means 14 having a conical shape is inserted in the direction of the arrow into the hollow space 53 of the contact element 5. The outer dimensions of the expanding means 14 are selected so that the material of the contact element 5 is moved radially outward, i.e., toward the inner surface 91 of the through hole 9, due to the conical shape of the expanding means 14. This causes the contact element 5 to make contact with the conductive material 92 on the inner surface 91 of the through hole 9, forming a conductive connection. The expanding means 14 shown in Figure 6 may be an object that remains in the hollow space 53 of the contact element 5, or it may be an operating area (Arbeitsbereich) of a tool that is removed again from the hollow space 53 of the contact element 5 after expanding.

[0053] Figure 7 shows an enlarged partial cross-sectional view of the resistor assembly 2 according to Figure 6 after the tool used to enlarge it has been removed. Thus, Figure 7 is a partial cross-sectional view of the apparatus 1 for measuring current intensity by the resistor assembly 2.

[0054] Figure 8 shows a partial cross-sectional view of a device 1 for measuring current intensity, as another embodiment, which includes a resistor assembly 2 and a conductor substrate 8 positioned on the resistor assembly 2. The contact element 5 has a circumferential step 51 on which the conductor substrate 8 rests. For this purpose, in the portion of the contact element 5 directly adjacent to the connecting element 3, the outer dimensions of the contact element 5 are formed to be larger than the inner width of the through-hole 9 in the conductor substrate 8. Therefore, the conductor substrate 8 does not rest on either the connecting element 3 or the resistor element 4 without additional spacers. The height of the step 51 was already taken into consideration when molding the contact element 5 from the material of the connecting element 3. Contact between the contact element 5 and the conductor substrate 8 is made in the same manner as in the embodiment shown and described in connection with Figure 6.

[0055] Figure 9 shows a partial cross-sectional view of an apparatus 1 for measuring current intensity, as another embodiment, comprising a resistor assembly 2 and a conductor substrate 8 positioned on the resistor assembly 2. The contact element 5 has a section 55 with a conical outer contour directly adjacent to the conductor substrate 8 between the connecting element 3 and the conductor substrate 8. Furthermore, the contact element 5 has a projection 56 on the conductor substrate 8. In the region of the projection 56, the contact element 5 expands conically. As a result, the contact element 5 protrudes laterally onto the upper surface 81 of the conductor substrate 8. The conical expansion of the contact element 5 in the region of its projection 56 moves the conductor substrate 8 toward the connecting element 3, thereby pressing it against the conical section 55 of the contact element 5 between the conductor substrate 8 and the connecting element 3. In this way, the conductor substrate 8 is forcefully fixed in the direction of the longitudinal axis A of the contact element.

[0056] For better expressiveness, the present invention has been described using, as exemplary in Figures 1 to 9, a resistor assembly 2 comprising only one resistor element 4 and two terminal connector elements 3, 3'. The above method can also be applied to a resistor assembly having two or more resistor elements and at least one additional connector element positioned between the two resistor elements in a possible current path. In this case, the resistor assembly can be configured such that the same current flows through at least two resistor elements, thereby enabling duplicated current measurement, or so that different currents flow through at least two resistor elements, thereby enabling partial current measurement. In these cases, the method for forming the contact elements 5 and creating electrical connections with the conductive substrate 8 described above, based on the description, Figures 1 to 9, and embodiments, can also be used to form one or more contact elements 5 from the material of the connector element positioned between the two resistor elements. [Explanation of Symbols]

[0057] 1 device 2 Resistor Assembly 3, 3' connecting element 4 Resistor elements 5 Contact elements 51 Step part 52 End face 53 Hollow space 55 categories 56 Protrusion 8 Conductor substrate 81 Top surface 9 Through hole 91 Inner surface 92 Conductive materials 11 punches 12 negative type 121 Cavity 122 Internal tools 14. Expanding means A Long axis H Height T Penetration depth D Thickness

Claims

1. A method for manufacturing a device for measuring current intensity using a resistor assembly, the method being: a) Providing a resistor assembly comprising at least two connecting elements and at least one resistive element disposed between the connecting elements in the direction of current, wherein the at least one resistive element is made of a first conductive material and the connecting elements are made of a second conductive material different from the first conductive material, b) A step of forming at least one contact element from the second conductive material of at least one of the at least two connecting elements, or from the first conductive material of the resistive element, wherein the contact element has a longitudinal axis defining an axial direction and a radial direction perpendicular thereto, and the contact element is formed to have an end face away from the resistive assembly and a hollow space opened at the end face of the contact element away from the resistive assembly, c) Providing a conductive substrate having at least one through hole having an inner surface provided with a third conductive material, d) The step of positioning the conductor substrate on the resistor assembly such that the conductor substrate has an upper surface separated from the resistor assembly and at least one contact element protrudes at least into the through hole, e) A method comprising the step of radially expanding the contact element with an expanding means, wherein the expanding means is inserted axially into the hollow space of the contact element, thereby creating a conductive connection between the contact element and the third conductive material on the inner surface of the through hole.

2. The method according to claim 1, characterized in that the expanding means is formed such that the expansion of the contact element is performed by inserting the expanding means.

3. The method according to claim 1, characterized in that the expanding means is formed such that the expansion of the contact element occurs after the expanding means is inserted.

4. The method according to claim 1, characterized in that the expansion in step e) creates a force-coupled connection between the inner surface of the through hole in the conductor substrate and the contact element.

5. The method according to claim 1, characterized in that the contact element has a height selected such that, after positioning the conductor substrate, the end face of the contact element that is separated from the resistor assembly is located within the through hole of the conductor substrate or terminates flush with the upper surface of the conductor substrate.

6. The method according to claim 1, characterized in that the molding of the contact element in step b) is carried out by an embossing step or fluid press molding.

7. The method according to claim 6, characterized in that, in order to shape the contact element, a negative mold is used having at least one cavity corresponding to the outer contour of the contact element and at least one internal tool positioned in the cavity for shaping the hollow space, and during step b), the internal tool is moved relative to the cavity in the direction of the longitudinal axis of the contact element.

8. The method according to claim 1, characterized in that the expansion of the contact element in step e) is assisted by heating the material of the contact element with ultrasound or a laser.

9. An apparatus for measuring current intensity comprising a resistor assembly and a conductive substrate mechanically and electrically connected to the resistor assembly, wherein the resistor assembly comprises at least two connecting elements and at least one resistive element disposed between the connecting elements in the direction of the current, the at least one resistive element being made of a first conductive material, and the connecting elements being made of a second conductive material different from the first conductive material. In an apparatus in which the conductive substrate comprises an upper surface separated from the resistor assembly and at least one through-hole having an inner surface provided with a third conductive material, The resistor assembly has at least one contact element having a longitudinal axis, which is monolithically connected to one of the connecting elements and made from the second conductive material of the connecting element, or monolithically connected to the resistor element and made from the first conductive material of the resistor element, wherein the resistor assembly is electrically and mechanically connected to the conductor substrate by the contact element, which at least protrudes into the through hole of the conductor substrate and is forcefully connected to the third conductive material on the inner surface of the through hole. The apparatus is characterized in that the contact element has an end face separated from the resistor assembly and a hollow space opened at the end face of the contact element separated from the resistor assembly, and the contact element has a conical contour at the transition portion from its end face to the hollow space.

10. The apparatus according to claim 9, characterized in that the contact element has a height selected such that the end face of the contact element, separated from the resistor assembly, is located within the through hole of the conductor substrate or terminates flush with the upper surface of the conductor substrate.

11. The apparatus according to claim 9, characterized in that the contact element has a protrusion on the conductor substrate on the side of the conductor substrate away from the resistor assembly, and in the region of this protrusion, it is spread laterally to fix the conductor substrate.

12. The apparatus according to claim 11, characterized in that the contact element comprises a section having a conical outer contour between the connecting element and the conductive substrate, thereby increasing the cross-sectional area of ​​the contact element toward the connecting element.

13. The apparatus according to claim 9, characterized in that the at least one contact element has a stepped portion on which the conductor substrate rests, such that the conductor substrate is separated from the resistor assembly.

14. The apparatus according to claim 9, characterized in that the at least one contact element has a surface having a metal coating, particularly a tin-containing, silver-containing, or nickel-containing coating.

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