Contact sleeve for an electric plug connection construction

Abstract

The present invention relates to a contact sleeve (2) for an electric plug connection construction with a catch spring (24), which is designed to latch into a form-fit contour as a safeguard against removal of the contact sleeve (2) (following assembly of the latter by being plugged in) in a housing of the plug connection construction and which, in order to latch in place, protrudes laterally from the contact sleeve (2), characterised in that the cross-section of the catch spring (24) (transverse to the plugging direction of the contact sleeve), between its form-fit edge (28) pointing counter to the plugging direction and the front edge (30) of the contact sleeve (2) pointing in the plugging direction, at least over a region of its extent in the plugging direction of the contact sleeve (2), is assembled from at least three cross-section regions (34, 36, 38) each with two edges (40) substantially parallel to one another, which are connected to one another in transition regions, in which the regions change the direction of their parallel edges (40) by at least 60° or 70° or 80° or 90° or more than 90°, and, in this region of their extent, is connected to the contact sleeve (2).

Description

[0001] Contact sleeve for an electrical connector construction

[0002] The invention relates to an electrical contact sleeve, preferably a miniaturized contact sleeve, with a snap spring projecting from the contact for locking the contact sleeve in a form-fitting contour of a housing of a plug-in connection construction.

[0003] Such electrical contact sleeves are usually punched and bent from sheet metal and have a connection area for an electrical cable and a plug-in area with a tubular contact area with a rectangular or even square tube cross-section, which forms a receiving space for an electrical pin or pin contact. The tubular contact area usually has a rectangular or square cross-section with edges bent into a quarter-circle in cross-section and thus usually has a base wall with two side walls, of which an upper free edge of one of the side walls is bent over the base wall parallel to it and thus completes the rectangular cross-section with a top wall.When a pin contact is inserted into such a contact sleeve, specifically in its tubular contact area, the side walls, the bottom wall and the top wall of the contact area mechanically fix the pin contact in the sleeve. Electrical contact is preferably made via a contact spring located in the contact area, which is usually formed integrally with the contact sleeve. At the other end of the contact sleeve, opposite the contact area, the electrical line can be connected mechanically, preferably via a crimp connection, and electrically via a contact weld or a crimp connection - all of this also according to the invention.

[0004] By plugging together a pin contact with such a contact sleeve, which is also according to the invention, an electrical connection for a cable can be quickly established. And by assembling, i.e. plugging in, several such contact sleeves together in a "plug housing" (a housing of an electrical plug connection construction) with the same, i.e. parallel, plugging direction, it is well known that several electrical contacts can be established at the same time. Contact sleeves are used in straight and angled designs for different types of electrical plug connections. For example, there are flat plugs for detachable electrical contact between a printed circuit board and a cable. The contact sleeves in plug housings already mentioned are used to detachable electrical contact by means of single or multi-core cables between devices or between an electrical device and a power supply.Such contact sleeves combined in connector housings are also widely used, not least in automobile construction.

[0005] In order to lock the contact sleeves in a plug housing, contact sleeves have a detent spring that preferably protrudes from the top wall of the tubular contact area. Such contact sleeves are usually bent from a blank punched out of sheet metal, with a gap being created between the detent spring and one of the side walls or the top wall of the contact sleeve. This gap can cause the cable to repeatedly become threaded under the detent spring when the contact sleeve is being assembled with the electrical cable. This hinders the assembly of the electrical cable and can, under certain circumstances, lead to damage to the contact sleeve. Due to the aim of miniaturization, the contact sleeve is becoming ever smaller and hence its punched sheet thickness ever thinner and thus ever more sensitive.

[0006] Due to advancing technological developments, such electrical contacts are being miniaturized, as already mentioned above, raising new problems in the design and layout of the contacts. Increasingly, importance is being attached to ensuring stable locking of the contact despite its small size, preventing the locking spring from kicking out, and preventing the cable from becoming entangled under the locking spring during electrical cable assembly.

[0007] It is therefore an object of the invention to improve the mechanical and handling qualities of an electrical contact sleeve, particularly preferably for automotive engineering. In particular, it is an object of the invention to create an electrical contact that, despite its miniaturized size, locks even more reliably into a housing, particularly with regard to the buckling of its locking spring under tensile stress on the electrical cable—and, not least, with regard to cable threading under the locking spring.

[0008] The object of the invention is achieved by a contact sleeve according to claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

[0009] The object of the invention is achieved by means of a contact sleeve for an electrical plug with a snap spring adapted to engage in a positive-locking contour as a pull-out protection for the contact sleeve in a plug housing (namely, after its assembly by insertion into the plug housing). The snap spring protrudes laterally from the contact sleeve for engagement.

[0010] According to the invention, the cross section of the snap spring (transverse to the plug-in direction of the contact sleeve) between its form-fitting edge pointing against the plug-in direction and the front edge of the contact sleeve pointing in the plug-in direction is composed of three cross-sectional areas with two edges that are essentially parallel to one another, at least over a region of its extension in the plug-in direction of the contact sleeve, which are connected to one another in transition areas in which the areas change the direction of their parallel edges by at least 60° or 70° or 80° or 90° or more than 90°. In this region of its extension, the snap spring is also otherwise connected to the contact sleeve, in particular, particularly preferably as a sheet metal part, in one piece.

[0011] Finite element analysis surprisingly revealed that this design creates different areas where the stress is greatest: firstly, when the snap spring engages in the housing during assembly (and is subjected to bending stress in the process) and secondly, when it is compressed, for example under tension on the contact sleeve, particularly at its rear end on the cable, because it has to withstand being pulled out and the resulting unwanted, accidental dismantling. These different areas of greatest stress in these two stress situations have the advantage that the area of ​​greatest stress does not already experience the greatest stress when resisting pulling out and is not previously damaged.In particular, however, this design according to the invention, which comprises three cross-sectional areas which are oriented in different directions relative to one another according to the invention, i.e. are particularly bent, and specifically also in an area in which the snap spring merges into the remaining plug contact, also results in the required extraction force (the resistance to extraction) being increased.

[0012] These technical effects and advantages are particularly evident when the snap spring according to the invention has an interruption, particularly preferably in the region of the extension which is composed of at least three of the cross-sectional areas, in the wall whose cross-section is formed by the middle of the two cross-sectional areas - and very particularly preferably a slot oriented transversely to the extension of the snap spring. The slot is advantageously simple in terms of design and production technology. But other contours of the interruption are also according to the invention. Thus, in the plan view of the (preferably flat) side of the snap spring interrupted by the interruption, the interruption can be rectangular, circular, oval, parallel to edges, straight or even in a combination of, for example, these contour shapes.

[0013] Overall, the cross-section of the snap spring (transverse to the plug-in direction of the contact sleeve) is composed of two cross-sectional areas (with two essentially parallel edges) over essentially its entire extent (which are connected to one another in a transition area in which the direction of the parallel edges of the areas changes by at least 60°, 70°, 80°, 90°, or more than 90°). This structure provides an additionally stiffened, and therefore even more robust, snap spring.

[0014] The contact sleeve is particularly preferably an electrical conduction element (or has one, for example in addition to an insulating sheath, for example in the form of a paint finish) which is punched and bent from sheet metal. This then results in the cross-sectional shape of the regions with (essentially) parallel edges in this sheet metal construction form of the contact sleeve, namely the cross-sectional edges of the top and bottom of the sheet metal, i.e. the sheet thickness. This type of production of contact sleeves is widespread and proven, and also according to the invention, not least for miniaturized contact sleeves. In particular in this type of production which includes bending, it is advantageous in terms of stress mechanics (and the shape results) that the direction of the parallel edges of the regions - continuously bent - changes in the transition regions.But also a change of direction that is bent or otherwise discontinuous is in accordance with the invention.

[0015] The tubular contact region of the contact sleeve according to the invention has a rectangular or square cross-section with parallel edges that are particularly curved in a quarter-circle shape in cross-section, and thus has a bottom wall with two side walls, of which an upper free edge of one of the side walls runs parallel over the bottom wall and thus completes the rectangular cross-section with a top wall. The snap spring can now be formed on the upper free end of the other side wall with the cross-section continuing vertically upwards, so that the basic shape of the number "6" is then produced in the cross-section through the contact sleeve according to the invention.However, the basic cross-sectional shape of a treble clef (without its vertical stroke) is particularly preferred, in that the snap spring is formed on the upper free end of the other side wall with a further cross-sectional profile that is initially changed to the horizontal (so that a second - double - top wall can result) and only then continues further upwards with a cross-sectional profile that can again be bent to the side further up - so that overall, for example, a C-shaped cross-section of the snap spring results.

[0016] Further advantages, embodiments and details of the invention are described below in the description of exemplary embodiments with reference to the attached figures. They show:

[0017] Figures 1 to 3 show three different spatial views, the third of which is in section, of a first embodiment of a contact sleeve according to the invention with an interruption of the longitudinal extension of the snap spring walls,

[0018] Figures 4 and 5 show two different spatial views of a second embodiment of a contact sleeve according to the invention without such an interruption, Figures 6 and 7 show two different spatial views of a third embodiment of a contact sleeve according to the invention without such an interruption,

[0019] Figures 8 and 9 show two different spatial views of a fourth embodiment of a contact sleeve according to the invention without such an interruption,

[0020] Figure 10 shows a cross-sectional area through a fifth embodiment of a contact sleeve according to the invention,

[0021] Figure 11 shows a force-displacement diagram of a FE pull-out

[0022] Simulation of a contact sleeve according to the invention in comparison with a prior art contact sleeve with only two cross-sectional areas with different directions over the entire extension of the detent spring,

[0023] Figure 12 a force-displacement diagram of a FE-deflection

[0024] From a spring simulation of a contact sleeve according to the invention in comparison with a prior art contact sleeve with only two cross-sectional areas with different directions over the entire extension of the detent spring,

[0025] Figure 13 shows two FE stress distribution images, namely during an FE deflection simulation in comparison with an FE tear-out simulation of a contact sleeve according to the invention with an interruption of the longitudinal extension of the snap spring walls, and

[0026] Figures 1 to 10 show five different electrical contact sleeves 2. These contact sleeves are punched and bent from sheet metal and all have a connection area 4 for an electrical line and a plug-in area with a tubular contact area 6 with a square tube cross-section, which forms a receiving space for an electrical pin or pin contact (not shown). The tubular contact area 6 has a square cross-section with edges 8 bent in the shape of a quarter circle in cross-section and thus has a base wall 10 and two side walls 12, 14, of which an upper free edge of one of the side walls 12 is bent over the base wall 10 parallel to the latter and thus completes the rectangular cross-section with a top wall 16.When a pin contact (not shown) is inserted into such a contact sleeve 2, specifically into its tubular contact area 6, the side walls 12, 14, the bottom wall 10 and the top wall 16 of the contact area mechanically fix the pin contact in the sleeve 6. Electrical contact is made between a first contact spring 18 located in the interior of the contact area 6, which is formed integrally with the bottom wall 10 and projects inwards in an arc shape, and a spiral spring contact 20, which is formed integrally with one of the side walls 12 and the top wall 16 and runs inwards from these two walls 12, 16 in the plug-in direction P of a pin contact (not shown) into the contact sleeve 2.

[0027] At the other end of the contact sleeve 2, opposite the contact area 6, an electrical line (not shown) can be mechanically and electrically connected via a crimp connection 22.

[0028] By plugging a pin contact (not shown) together with the respective contact sleeve 2, an electrical connection for a cable (not shown) can be quickly established. And by assembling, namely by plugging, several of the contact sleeves 2 together in a "plug housing" (not shown - a housing of an electrical plug connection construction) with the same, namely parallel, plugging direction, several electrical contacts can be established simultaneously.

[0029] In order to lock the contact sleeves 2 in a plug housing (not shown), the contact sleeves all have a laterally projecting detent or snap spring 24 which is adapted to engage in a form-fitting contour (not shown) as a pull-out protection for the contact sleeve in a plug housing (not shown - namely after its assembly by plugging into the plug housing). As mentioned, the snap spring 24 protrudes laterally from the contact sleeve 2 for engagement.

[0030] The cross section 26 of the snap spring 24 (transverse to the plug-in direction of the contact sleeve) between the form-fitting edge 28 pointing against the plug-in direction K of the contact sleeve 2 and the front edge 30 of the contact sleeve 2 pointing in the plug-in direction K is composed, over a region 32 of its extension in the plug-in direction K of the contact sleeve, of three cross-sectional regions 34, 36, 38 with two essentially parallel edges 40, which are connected to one another in transition regions 42, in which the regions 34-39 change the direction of their parallel edges 40 by 90°. In this region 32 of its extension, the snap spring 24 is also otherwise connected to the contact sleeve 2 in a transition region 44, specifically as a single piece of sheet metal.

[0031] The snap spring of the contact sleeve 2 according to Figures 1-3 has in the region 32 of the extension, which is composed of the three cross-sectional regions 34-38, in the wall 46, the cross section 36 of which is formed by the middle of the three cross-sectional regions, an interruption 48 - namely a slot 48 oriented transversely to the extension of the snap spring 24.

[0032] The tubular contact area 6 of the contact sleeves 2 with its square cross-section consisting of the bottom wall 10 and the two side walls 12, 14 is then, as already mentioned above, completed with a top wall 16 which runs from the upper free edge of one of the side walls, the side wall 12, parallel over the bottom wall 10.

[0033] The snap spring 24 can now be formed according to Figure 10 at the upper free end of the other side wall 14 with a cross-sectional profile 34 that continues vertically upwards (into the first cross-sectional area 34, which then bends horizontally into the second cross-sectional area 36 and again downwards into the third cross-sectional area 38), so that the cross-section through the contact sleeve 2 according to Figure 10 then results in the basic shape of the number "6".

[0034] 1-7, however, show the basic cross-sectional shape of a treble clef (without its vertical stroke), in that the snap spring 24 is formed on the upper free end of the side wall 14, but now with a further cross-sectional profile that is initially changed to the horizontal (into the first cross-sectional area 34 - so that a second - double - top wall is produced - which then leads vertically upwards into the second cross-sectional area 36 and then bends back horizontally into the third cross-sectional area 38) - so that a C-shaped cross section 34-38 of the snap spring 24 is produced. The design according to Figures 6 and 7 even has a snap spring 24 made up of four cross-sectional areas 34-39, the fourth of which ultimately leads downwards again.

[0035] The cross section of the snap springs 24 (transverse to the plug-in direction K of the contact sleeves 2) is made up of the three cross-sectional areas 34-39 according to Figures 4, 5, 8 and 9 and of the four cross-sectional areas 34-39 according to Figures 6 and 7 (which are connected to one another in transition areas 42 in which the direction of the parallel edges 40 of the areas 34-39 changes by 90°) over essentially the entire extent of the snap spring 24. All of the embodiments according to Figures 1-9 have a short end area 50 made up of only one such cross-sectional area only at the latching end 28 of the snap spring 24, which represents ribbing for stiffening downward stresses when resisting withdrawal of the contact sleeve 2 from the latching (not shown). Only the embodiment according to Figures 1-3 has a partial extension area consisting of three of the cross-sectional areas 34-38, and the remaining extension area consists (with the exception of the end section 50) of two of them.

[0036] Finite element analyses have shown that, in particular, design 2 according to Figures 1-3 with the interruption 48 provides different areas 52, 54 of the snap spring 24 (see Figure 13) in which the load is greatest, firstly when the snap spring 24 engages during assembly in the housing (not shown) (and is subjected to bending stress in the process) and secondly when it is compressed, for example under tension on the contact sleeve, in particular at its rear end 4 on the cable (not shown), because it has to withstand being pulled out and the resulting unwanted, accidental disassembly. These different areas 52, 54 of greatest load in these two stress situations have the advantageous effect that the area of ​​greatest load 54 does not already experience the greatest load when resisting pulling out and is not previously damaged.Figure 13 shows two FE stress distribution images, namely during an FE deflection simulation in comparison with an FE tear-out simulation of the contact sleeve 2 according to Figures 1-3 with the interruption 48 of the longitudinal extension of the snap spring walls 46.

[0037] In particular, however, the design 2 according to Figures 4 and 5, comprising three cross-sectional areas 34-38 which, according to the invention, are oriented in different directions relative to one another, i.e. are particularly bent, and specifically also in an area 44 in which the snap spring 34 merges into the remaining plug contact, ensures that the required pull-out force (the resistance to pulling out the contact sleeve 2) 56 is greater than the required pull-out force 58 for a conventional snap spring with an L-shaped cross-section (not shown), i.e. with only two of the cross-sectional areas (Figure 11).

[0038] Figure 12 shows a force-displacement diagram of an FE compression-rebound simulation of the contact sleeve according to Figures 4 and 5 in comparison with one from the prior art (not shown) with only two cross-sectional areas with a different direction to each other over the entire extent of the detent spring - and makes it clear that the permanent deformation (the hysteresis 60 on the x-axis of the diagram) is advantageously lower in the contact sleeve according to the invention: the detent spring according to the invention springs back more strongly, i.e. deeper into the detent (not shown).

[0039] Figure 12 further shows, for the snap spring according to the invention, a lower maximum deformation force, thus a lower stress load, for the same deflection travel. The underlying FE simulation experiment also revealed less concentrated, more evenly distributed stresses (not shown) in the stress distribution across the entire surface of the snap spring in FE stress distribution diagrams (not shown) for the snap spring according to the invention. Since the contact sleeves 2 are made of thin sheet metal, thus with a certain degree of structural sensitivity, this lower load on the safety-relevant component of the snap spring 24 is a significant advantage of the invention. List of reference symbols

[0040] Contact sleeve 2

[0041] Electrical connection area 4

[0042] Tubular contact area 6

[0043] Quarter-circle shaped curved edges 8

[0044] Bottom wall 10

[0045] Side walls 12 , 14

[0046] Ceiling wall 16

[0047] Arched contact spring 18

[0048] Bending spring contact 20

[0049] Plugging direction P of a pin contact

[0050] Crimp connection 22

[0051] Snap spring 24

[0052] Cross section 26 of the snap spring 24

[0053] Plugging direction K of contact sleeve 2

[0054] Form-fitting edge 28 of the snap spring 24

[0055] Front edge 30 of the contact sleeve 2

[0056] Extension area 32 from three cross-sectional areas 34, 36, 38 Cross-sectional areas 34, 36, 38, 39 of the snap spring 24

[0057] Parallel edges 40 of the cross-sectional areas 34 , 36 , 38 , 39

[0058] Transition areas 42 between areas 34-39

[0059] Transition area 44 of the snap spring 24 to the contact sleeve 2

[0060] Wall 46 of the snap spring 24 with the middle of the three cross-sectional areas 34-38

[0061] Interruption, slot 48

[0062] End area 50 of the snap spring 24

[0063] Area 52 of greatest load on the snap spring 24 during compression and locking

[0064] Area 54 of greatest load on the snap spring 24 when tearing out, under tension at the cable end 4

[0065] Tensile force 56 in a contact sleeve according to the invention 2 )

[0066] Tensile force 58 for a conventional snap spring with L-shaped cross-section

[0067] Permanent deformation, hysteresis 60 during a FE compression-rebound simulation of a snap spring according to the invention compared to a conventional one with an L-shaped cross-section

[0068] Maximum deformation force 62 during a FE compression-rebound simulation for a snap spring according to the invention compared to a conventional one with an L-shaped cross-section

Claims

Claims 1. Contact sleeve (2) for an electrical connector assembly with a snap spring (24) which is adapted for engaging in a positive locking contour as a pull-out protection of the contact sleeve (2) in a housing of the connector assembly and which projects laterally from the contact sleeve (2) for engagement, characterized in that the cross-section (26) of the snap spring (24) between its positive locking edge (28) facing against the insertion direction and the front edge (30) of the contact sleeve (2) facing in the insertion direction is composed of at least three cross-sectional areas (34, 36, 38, 39) each with two substantially parallel edges (40) which are connected to each other in transition areas (42),in which the areas change the direction of their parallel edges (40) by at least 60° or 70° or 80° or 90° or more than 90° and in this area (44) of their extension is connected to the contact sleeve (2).

2. Contact sleeve (2) according to claim 1, characterized in that the snap spring (24) has an interruption (48) in the wall (46) in the area (32) of the extension which is composed of at least three of the cross-sectional areas (34, 36, 38, 39), the cross-section of which is formed by the middle of the two cross-sectional areas (36).

3. Contact sleeve (2) according to claim 2, characterized in that the interruption (48) is a slot (48) oriented transversely to the extension of the snap spring (24).

4. Contact sleeve (2) according to one of the preceding claims, characterized in that the cross-section (26) of the A snap spring (24) is composed, over substantially its entire extension in the insertion direction of the contact sleeve (2), of two cross-sectional areas with two substantially parallel edges (40) which are connected to each other in a transition area in which the direction of the parallel edges (40) of the areas changes by at least 60°, 70°, 80°, 90°, or more than 90°. A contact sleeve (2) according to one of the preceding claims, characterized in that the direction of the parallel edges (40) of the areas changes continuously in at least one of the transition areas (43). A contact sleeve (2) according to one of the preceding claims, characterized in that the contact sleeve (2) is or comprises an electrical conducting element (2) that is stamped and bent from sheet metal.

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