Contact element producible burr-free

Abstract

The invention relates to an electrical contact element (1), wherein the lead content of the contact element (1) is less than or equal to 0.1% by weight, which contact element (1) has at least one first region (KB) and at least one second region (AB) adjacent thereto, wherein at least a partially circumferential groove (2) is provided between the first region (KB) and the second region (AB). The contact element can thus be produced without burrs.

Description

Technical Field

[0001] The present invention relates to an electrical contact element according to the preamble of independent claim 1.

[0002] Contact elements engage with suitable mating contact elements to transmit current or electricity. These contact elements are used, for example, in mating connectors, but can also be mounted on so-called busbars. Particularly in industrial environments, these mating and mating connectors are used to establish electrical and mechanical connections between two electrical lines or between an electrical line and equipment. Background Technology

[0003] WO 2020 / 043231 A1 discloses a plug connector comprising a plug connector housing and at least one electrical contact element, wherein the lead content of the plug connector housing and / or the electrical contact element is less than 0.1% by weight.

[0004] WO 2020 / 043231 A1 also discloses a method for manufacturing so-called lead-free contact elements. This is done using a rotary machine tool with multiple workstations, which specifically perform cutting steps on the workpiece. In the following text, materials with a lead content of less than or equal to 0.1% by weight are referred to as lead-free materials.

[0005] The aforementioned contact element is made of lead-free material, thus conforming to popular environmental awareness. Machining steps are particularly used in the manufacturing of this contact element.

[0006] Typical machining processes include drilling, milling, turning, and sawing. Excess material generated during machining is removed as chips. Chips or non-acidic (sauer) removed material that remain on the workpiece after machining are called burrs.

[0007] It has been found that lead-free materials have a high burr formation rate compared to workpieces made of lead-containing materials, requiring an additional deburring step before use.

[0008] The German Patent and Trademark Office found the following prior art in the priority applications of this application: US 3,980,387 A, DE 10 2013 009 131 A1, US 2008 / 0107016 A1, DE 10 2016 217 673 A1, US 2010 / 0072923 A1 and WO 2020 / 043231 A1. Summary of the Invention

[0009] The purpose of this invention is to provide an environmentally friendly and easy-to-manufacture contact element.

[0010] This objective is achieved through the subject matter of the independent claims.

[0011] Advantageous embodiments of the invention are given in the dependent claims and in the following description.

[0012] The electrical contact element according to the invention has at least one first region and at least one second region. These two regions are adjacent to each other. Alternatively, these two regions are said to be adjacent to each other, although it is preferably an integral part herein.

[0013] The first region is preferably designed to be substantially cylindrical, while the second region is preferably designed to be substantially cubic.

[0014] The essentially cubic shape of the second region means that it can still have a partially cylindrical shape, with two flat, opposing side surfaces milled or machined into the original cylinder. The remaining two side surfaces correspond to the partial outer surfaces of the original cylinder, and are also referred to below as curved surfaces.

[0015] The first region of the contact element preferably includes an insertion region for making electrical contact with a mating contact element. The second region of the contact element preferably includes a connection region for making electrical contact with an electrical conductor or with a busbar.

[0016] According to the invention, the first region and the second region are separated from each other by a groove that at least partially surrounds each other. This groove at least partially surrounds the interface surface between the two regions. Without the groove, subsequent operations such as brushing, sandblasting, or vibratory grinding of the workpiece would be necessary, which would increase overall manufacturing costs and make the product more expensive.

[0017] According to the invention, the contact element may also have two or more regions and correspondingly have multiple grooves according to the invention. According to the invention, the first and second regions are separated from each other by grooves that at least partially surround each other. The third region may, for example, be adjacent to the second region and separated from it by a groove according to the invention. If the second region is substantially cubic in shape, then the third region is correspondingly cylindrical. In the invention, two adjacent regions have correspondingly different geometries and are separated from each other by grooves according to the invention.

[0018] The contact element is made of a material with a low lead content (less than or equal to 0.1% by weight). Advantageously, the contact element (1)

[0019] ---Made of a copper-zinc alloy (CuZn) with a zinc content of 35% to 42% by weight.

[0020] ---Or made of a copper-tin alloy (CuSn) with a tin content of 4% to 8% by weight.

[0021] ---Or made of a copper-nickel alloy (CuNi) with a nickel content of 0.5% to 30% by weight.

[0022] ---Or made of a copper-nickel-zinc alloy (CuNiZn) with a nickel content of 10% to 20% by weight and a zinc content of 20% to 30% by weight.

[0023] --- It may be made of copper, or of low-alloy copper with an additional component of up to 3% by weight.

[0024] Contact elements with the required mechanical and electrical properties can be manufactured from these materials. For these materials, machining is not the optimal method for producing contact elements. Burrs often occur and must be removed in additional processing steps.

[0025] The grooves according to the invention effectively prevent the formation of burrs, which are generated in the boundary region between the first and second regions during the manufacturing of the contact element. During the manufacturing process of the contact element, the grooves can be set in parallel with other work steps at the workstation, i.e., simultaneously with other work steps, thus without incurring significant additional work or cost.

[0026] Advantageously, the first and second regions are separated from each other by a fully encircling groove. The groove also visually separates these regions. However, a fully encircling groove is unnecessary for suppressing chip formation. The groove only needs to extend to where burrs occur. This is especially true when the surfaces of a part intersect at acute angles. Nevertheless, from a manufacturing perspective, an encircling groove is advantageous because the part is rotationally symmetrical, and an encircling groove is easier to implement than a partially encircling groove without removing the machining tool.

[0027] In a preferred embodiment of the invention, the surrounding groove has a V-shaped cross-section. Here, the legs of the V-shaped cross-section are configured to be isosceles or isosceles. Such a groove can be easily achieved with a simple tool and correspondingly simple working steps.

[0028] Advantageously, the legs of the V-shaped cross-section are arranged at an angle between 25° and 120°, preferably between 60° and 90°. It has been proven that no burrs are present on the workpiece or contact element at these angular positions.

[0029] Alternatively, the groove can have a cup-shaped cross-section. The cup shape here refers to a cross-section where the legs are curved in at least one area. This curvature is preferably achieved in the upper part or outer part of the groove. In this way, especially when the groove is deep, burrs can be prevented from forming on the workpiece overall, particularly along the groove.

[0030] In another alternative embodiment of the invention, the cross-section of the groove has two geometrically different legs: one leg is straight, resembling a V-shape, and the other leg is curved, resembling a cup shape. Depending on the depth of the groove, this geometry can effectively prevent the formation of burrs.

[0031] Preferably, the depth of the groove is equivalent to a maximum of 25% of the outer diameter of the first region of the contact element. Such a groove depth has proven to prevent burr formation and does not significantly affect the electrical performance of the contact elements of industrial plug connectors (also known as heavy-duty plug connectors).

[0032] However, it is preferable that the groove depth is selected to be a maximum of 10% of the outer diameter of the first region of the contact element. This also prevents the formation of burrs, and the electrical performance of the contact element (such as current carrying capacity) is not affected. Advantageously, the absolute depth of the groove is between 0.01 mm and a maximum of 10 mm, with the edge region also included within this depth range.

[0033] If the contact element is subsequently coated with a precious metal or a precious metal alloy to improve conductivity, especially current carrying capacity, then a very shallow groove has an advantage.

[0034] The contact element according to the invention is preferably a so-called pin element. In a preferred embodiment of the invention, the first region tapers at least partially towards the end of the contact element. This means that, viewed from the insertion direction, the diameter of the contact element gradually tapers towards the end. This allows the mating contact element (typically a socket contact) to easily engage.

[0035] Preferably, the first and second regions have a boundary region where they intersect. From a purely visual perspective, the two regions are adjacent in the boundary region. Here, the diameter of the first region corresponds to the edge length of the second region. In simpler terms, the two regions are constructed to be equally "strong" or "thick" in at least one plane within the boundary region, although these terms are not geometrically precise for a cubic shape. The transition between the two regions is uniform, with no gaps except for the groove according to the invention, which is advantageous for the current-carrying capacity of the contact element.

[0036] Advantageously, the grooves according to the invention, or these grooves, are so-called external grooves. These grooves have been machined onto the outer casing of the contact element.

[0037] Because the groove is introduced into the solid material through a cutting step, it is also called a spannut. For example, for contact elements produced by a stamping and bending process, such a spannut differs from a groove provided by a stamping technique.

[0038] Such grooves can be easily machined during the manufacturing process. However, the impact of the grooves on the current-carrying capacity must be considered. It is well known that the current-carrying capacity of contact elements is strongly affected by their surface, especially their surface geometry.

[0039] When manufacturing contact elements according to the present invention

[0040] - First, cut a workpiece of appropriate length from a wire spool.

[0041] - Subsequently, a groove, at least partially surrounding the workpiece, is provided on the workpiece, which separates the first region KB and the second region AB from each other.

[0042] - In parallel or shortly thereafter, a first region for contact with mating contact elements and a second region for electrical contact with conductors or busbars are formed.

[0043] Alternatively, the rod can be rotated and the workpiece shaped according to the invention. Multiple contact elements according to the invention can be manufactured from a single rod.

[0044] The workpiece is made of a copper-zinc alloy with a lead content of less than or equal to 0.1% by weight.

[0045] After the geometry of the contact element is completed, it is preferable to deposit a pure silver, silver alloy, pure gold, or gold alloy coating on its surface during the electroplating process. Attached Figure Description

[0046] Embodiments of the present invention are shown in the accompanying drawings and explained in more detail below. Wherein:

[0047] Figure 1 A perspective detail view of the contact element is shown;

[0048] Figure 2 A perspective detail view of the contact element according to the present invention is shown;

[0049] Figure 3 A perspective view of the contact element according to the present invention is shown;

[0050] Figure 4 Different cross-sections of the groove according to the invention are shown; and

[0051] Figure 5 An engineering drawing of an alternative contact element according to the present invention is shown.

[0052] These accompanying drawings contain partially simplified schematic diagrams. In some cases, the same reference numerals are used for the same, but may not be, the same element. Different views of the same element may be at different scales. Detailed Implementation

[0053] Figure 1and Figure 2 A perspective detail view of contact elements 1 and 1' is shown. These contact elements 1 and 1' consist of a first region KB and a second region AB. The first region KB is used for electrical contact with mating contact elements, and the second region AB is used for electrical contact with an electrical conductor or busbar. These two regions AB and KB can only be used in… Figure 3 You can see the complete version in the middle. Figure 1 and 2 The focus is on the adjacent portions of the two regions AB and KB of contact elements 1 and 1'. This region is also referred to as the boundary region below.

[0054] The first region KB is essentially cylindrical, tapering towards the insertion side (i.e., towards the contact tip). The second region AB is essentially cubic. The diameter D1 of the first region corresponds to the side length K1 of the second region (K1 = D1) in the boundary region. From the boundary region to the contact tip, the diameter D of the first region KB changes. The diameter D of the first region KB does not continuously decrease. This diameter D alternates at least once in this region, that is, the previous diameter D2 is smaller than the subsequent diameter D3.

[0055] The second region AB is formed from a cylinder, in which two flat side surfaces 3a are introduced. The remaining curved side surfaces 3b continue to correspond to part of the outer casing of the original cylinder. Therefore, the second region AB is essentially cubic. It has two opposing flat side surfaces 3a and two opposing curved or arcuate side surfaces 3b. The curvature of these arcuate side surfaces corresponds to the curvature of the cylindrical first region KB.

[0056] exist Figure 2 As can be seen, a groove 2, at least partially surrounding the first region KB and the second region AB, is provided in the boundary region. With the second region AB having its flat side surface 3a, the groove 2 extends only on one side. In this case, "one side" means that a ramp 4 exists on the first region KB. The geometry or design of this ramp 4 is the same as the cross-section of the associated leg of the groove 2. That is, the groove 2 continues to extend uniformly in the region of the ramp 4, and therefore can also be described as a completely surrounding groove 2, 4. This ramp 4 is a remnant of the completely surrounding groove provided on the workpiece before the formation of the flat side surface 3a.

[0057] exist Figure 3 As can be seen, the contact element 1 has a through opening 5 in the second region AB. The contact element 1 can be electrically fixed to the busbar (not shown). Alternatively, the electrical conductor can be provided with screw fixing or crimp connection in the second region.

[0058] exist Figure 4Different cross-sections of the grooves 2, 2', and 2" according to the present invention can be seen. In the first embodiment ( Figure 4 (Left side), the groove 2 has a V-shaped cross-section, wherein the two legs of the V-shape are isosceles and form a 90° angle. In the second embodiment ( Figure 4 In the middle), the groove 2' also has a V-shape, wherein the V-shaped legs are not isosceles. These legs are also arranged at a 90° angle. In the third embodiment ( Figure 4 On the right), groove 2” also has a cup-shaped cross-section, in which the legs are curved and symmetrical.

[0059] Figure 4 The legs of the groove cross-section shown can be arranged arbitrarily as needed. In any case, this inventive concept will continue to be realized. In this respect, all relevant groove types can prevent the formation of burrs on the contact element 1 as needed.

[0060] Figure 5 An alternative structural form of the contact element 1” according to the invention is shown. The contact element 1” is configured as a socket contact. Therefore, in the first region KB, i.e., in the so-called contact area, various axially projecting sheets 6 are formed, which surround the pin contact in their contact area. A surrounding groove 2 is provided between the first region KB and the second region AB to prevent burrs from forming at this location during manufacturing.

[0061] The first region KB of the contact element 1” is basically cylindrical, wherein the sheets 6 form a cylindrical outer cover, and the sheets 6 are separated only by axially extending gaps.

[0062] The second region AB can have the shape of a double cylinder (two stacked cylinders).

[0063] Alternatively, one element in the connection area of ​​the contact element can be designed as a cube, and the connected element as a cylinder. From a manufacturing perspective, it makes sense to further divide the connection area into a second region AB and a third region ZB, as in, for example, in... Figure 5 As shown by the dashed line. Therefore, a surrounding groove 2' is provided between the second region AB and the third region ZB. In this case, the contact element 1” will have two grooves 2, 2', which are configured to be completely or partially surrounding.

[0064] Even though aspects or features of the invention are shown in combination in the figures, it will be apparent to those skilled in the art that, unless otherwise stated, the combinations shown and discussed herein are not the only possible combinations. In particular, corresponding units or feature assemblies from different embodiments are interchangeable.

[0065] List of reference numerals

[0066] 1. Contact element

[0067] KB: Area 1

[0068] AB: Second Region

[0069] ZB: Third Region

[0070] D: Diameter

[0071] 2. Groove 3 a: Flat side surface of the second region AB

[0072] b: The rounded side surface of the second region AB

[0073] 4. Inclined surface of groove 2

[0074] 5. Through opening

[0075] 6 thin slices

Claims

1. An electrical contact element (1), wherein the contact element (1) has at least one first region (KB) and at least one second region (AB) adjacent thereto. The first region (KB) of the contact element (1) includes an insertion region for electrical contact with a mating contact element, and the second region (AB) of the contact element (1) includes a connection region for electrical contact with an electrical conductor or busbar. In the boundary region between the first region (KB) and the second region (AB), the first region (KB) is cylindrical, and the second region (AB) is cubic, having two opposing flat side surfaces (3a) and two opposing curved or arcuate side surfaces (3b). A circumferential groove (2) is provided between the first region (KB) and the second region (AB), wherein the groove (2) extends only on one side when the second region (AB) has its flat side surface (3a), wherein one side means that there is a slope (4) on the first region (KB).

2. The electrical contact element (1) according to claim 1, characterized in that, A completely surrounding groove (2, 4) is provided between the first region (KB) and the second region (AB).

3. The electrical contact element according to any one of the preceding claims, characterized in that, The surrounding groove (2) has a V-shaped cross-section.

4. The electrical contact element according to claim 3, characterized in that, The legs of the cross section are designed to be isosceles or isosceles.

5. The electrical contact element according to claim 4, characterized in that, The legs of the V-shaped cross section form an angle between 25° and 120°.

6. The electrical contact element according to claim 5, characterized in that, The legs of the V-shaped cross section form an angle between 60° and 90°.

7. The electrical contact element according to any one of claims 1 to 2, characterized in that, The groove has a cup-shaped cross-section.

8. The electrical contact element according to any one of claims 1 to 2, characterized in that, The groove has a cross-section with two legs, one of which is designed to be straight and the other is designed to be curved.

9. The electrical contact element according to any one of claims 1 to 2, characterized in that, The depth of the groove is equivalent to a maximum of 25% of the outer diameter of the first region of the contact element.

10. The electrical contact element according to claim 9, characterized in that, The depth of the groove is equivalent to a maximum of 10% of the outer diameter of the first region of the contact element.

11. The electrical contact element according to any one of claims 1 to 2, characterized in that, The depth of the groove is from 0.01 mm to 10 mm.

12. The electrical contact element according to any one of claims 1 to 2, characterized in that, The first region tapers at least partially toward the end of the contact element.

13. The electrical contact element according to any one of claims 1 to 2, characterized in that, In the boundary region, the diameter (D1) of the first region corresponds to the side length of the second region.

14. The electrical contact element according to any one of claims 1 to 2, characterized in that, The electrical contact element is designed as a single unit.

15. The electrical contact element according to any one of claims 1 to 2, characterized in that, The lead content of the electrical contact element is less than or equal to 0.1% by weight.

16. The electrical contact element according to any one of claims 1 to 2, characterized in that, The contact element (1) - Made of a copper-zinc alloy (CuZn) with a zinc content of 35% to 42% by weight. - Or made of a copper-tin alloy (CuSn) with a tin content of 4% to 8% by weight. - Or made of a copper-nickel alloy (CuNi) with a nickel content of 0.5% to 30% by weight. - Or made of a copper-nickel-zinc alloy (CuNiZn) with a nickel content of 10% to 20% by weight and a zinc content of 20% to 30% by weight. - It may be made of copper, or of low-alloy copper with an additional component of up to 3% by weight.

17. The electrical contact element according to any one of claims 1 to 2, characterized in that, The contact element (1) is divided into three regions, namely the first region (KB), the second region (AB) and the third region (ZB), and grooves (2, 2') are respectively provided between the regions (KB, AB, ZB).

18. The electrical contact element according to claim 17, characterized in that, The groove (2) or these grooves (2, 2') are all external grooves.

19. The electrical contact element according to claim 17, characterized in that, The groove (2) or these grooves (2, 2') are chip grooves introduced into the solid material during the cutting process.

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