IMPROVED CONDUCTIVE SLEEVE AND METHOD FOR CONNECTING A CONDUCTOR SECTION TO THE CONDUCTIVE SLEEVE

Description

[0001] The invention relates to an electrically conductive sleeve, in particular a sleeve designed as a crimp sleeve, comprising at least one connecting section and at least one receiving section for receiving at least one stripped conductor section of an electrically conductive conductor. The invention further relates to a method for connecting the electrically conductive sleeve to a stripped conductor section. State of the art

[0002] For electrically connecting cables and wires to fixed or portable appliances, generators, or for joining multiple cables together, connection elements such as cable lugs or ferrules are typically used. These are designed to form a plug or screw connection at their end. At the opposite end, these ferrules have a tubular receiving section. An exposed electrical conductor of the cable, or one of the exposed electrically conductive strands of the cable, is inserted into this receiving section. The conductor is secured in the ferrule either by screws or by a crimping action. This establishes contact between the conductor material and the electrically conductive material of the ferrule for current transmission.

[0003] In crimping processes used to create a connection between the end sleeve and the stripped conductor, crimping tools are typically employed. These tools require crimping dies that are appropriate for each conductor and sleeve cross-section. The correct crimping dies are specified by various standards and may be indicated by an imprint on the crimping point of the end sleeve. Additionally, the required crimping points are usually marked by thin, elongated lines.

[0004] For connecting aluminum conductors, terminal elements or end sleeves are used whose receiving sections are significantly longer than those for copper conductors. With aluminum conductors, the extended receiving section and multiple crimping steps ensure the required electrical safety. However, the extended receiving section requires more installation space, which is often unavailable in junction boxes or distribution boxes, as these are designed for copper conductors.

[0005] Furthermore, when crimping the receiving section of the end sleeve, the resulting shape of the crimped receiving section is determined by the geometry of the crimping tool. If the actual cross-section of the conductor used is smaller than the nominal cross-section due to manufacturing tolerances or material savings, this can result in the conductor not being sufficiently mechanically and electrically secured in the deformed receiving section. In extreme cases, such a connection can fail due to thermal overheating. Moreover, the crimping marks used to date cannot guarantee the correct alignment and positioning of the crimping tool relative to the end sleeve. Therefore, the crimping tool can be applied to the edge or end of the receiving section in such a way that the conductor or individual wires are sheared off.This impairs mechanical stability and reduces electrical conductivity.

[0006] New pressing methods for the plastic deformation of receiving sections are already known, eliminating the need for press dies. In these methods, a conical mandrel is hydraulically extended under force control and pressed into the receiving section of the end sleeve along with the conductor section it contains. The advantages of this pressing technique are very high mechanical and electrical quality, achieved without tool changes using a single tool for a wide range of conductor cross-sections. However, a disadvantage is the significant asymmetrical deformation of the receiving section that results from the pressing technique when more than one pressing operation is performed consecutively along the length of the end sleeve. In this case, the pressing sleeve deforms into a circular segment or banana shape. Furthermore, precise central alignment of the mandrel on the receiving section is difficult with this pressing method.

[0007] FR 3 050 579 A1 describes an end sleeve for electrical cables, which has two openings or through-holes. To connect the sleeve to the stripped end of the cable, a conical recess is drilled through the openings and into the cable. A conical element in the form of a metal foam plate is then inserted into the drilled recess and crimped to the sleeve and cable using an expanding insert.

[0008] From DE 195 23 514 A1, a method for producing an electrical connection between two plastic-insulated cables using a crimp sleeve is known. The stripped cable ends are inserted into the crimp sleeve from both sides. A tubular crimping die with several through-holes is positioned over the crimp sleeve to provide a guide for the corresponding crimping mandrels. The crimping die consists of two joined half-shells and can be removed from the crimp sleeve after crimping. Description of the invention: Problem, solution, advantages

[0009] The invention is based on the objective of creating a modified, electrically conductive sleeve and a method for technically simple and precise connection of crimp sleeves to conductors using a crimp mandrel.

[0010] This problem is solved by the features specified in claim 1. Further advantageous embodiments of the invention are described in the dependent claims.

[0011] According to one aspect of the invention, an electrically conductive sleeve, in particular a crimped sleeve, is provided. The sleeve can be designed as an end sleeve. The sleeve can be made of an electrically conductive material, such as copper, a copper alloy, aluminum, an aluminum alloy, and the like. The sleeve can have an externally arranged insulator or be provided with an external coating. The coating can provide insulation, corrosion protection, mechanical protection, and the like.

[0012] The sleeve has at least one connecting section and at least one receiving section for receiving at least one stripped conductor section of an electrically conductive conductor. The connecting section and the receiving section are electrically conductive to each other. The receiving section and the connecting section of the sleeve may be integrally formed.

[0013] According to the invention, the receiving section has at least one positioning aid for positioning a press mandrel of a press tool on the outside of the receiving section, wherein the at least one positioning aid is designed as at least one recess in the receiving section.

[0014] The positioning aid provides a starting point for the mandrel or press mandrel of the pressing tool. It enables precise control of the deformation by the press mandrel and prevents lateral displacement or "slipping" of the mandrel tip on the receiving section of the sleeve.

[0015] According to a further aspect of the invention, a method for connecting a conductor to an electrically conductive sleeve is provided. The sleeve according to the invention can preferably be used for this purpose.

[0016] In one step, a stripped conductor section is placed within the volume of a receiving section of the sleeve. The sleeve is then positioned with the conductor section arranged in the receiving section such that the tip of a mandrel of a crimping tool engages positively with a positioning aid located on the outside of the receiving section.

[0017] The tip of the press mandrel can interact with the positioning aid in the form of a recess in a form-fitting and / or force-fitting and / or friction-fitting manner.

[0018] In particular, the tip of the press mandrel may protrude into the positioning aid, collide with the positioning aid, or be slowed down or blocked by the positioning aid. Specifically, the positioning aid may prevent lateral movement and movement of the press mandrel towards the sleeve.

[0019] To create a connection between the conductor section and the receiving section, the mandrel is inserted into the receiving section using the positioning aid, deforming a portion of the receiving section. This movement of the mandrel can be force-controlled, for example. The receiving section is supported on the side opposite the positioning aid by a support of the pressing tool, so that the receiving section of the sleeve is compressed, at least partially, between the mandrel and the support. The positioning aid provides a precise point of application for the tip of the mandrel, allowing the entire deformation process to be carried out precisely and repeatably.

[0020] The positioning aid can be designed in the form of a recess into which the tip of the press mandrel can protrude. The positioning aid is preferably arranged or incorporated along the circumference of the receiving section of the sleeve. In particular, the positioning aid provides a knurled surface for the press mandrel.

[0021] Furthermore, the positioning aid allows the pressing operations to be carried out with such precision along the receiving section that multiple pressing operations acting in opposite directions can be performed consecutively along the longitudinal direction of the pressing sleeve, thus counteracting banana-like deformation of the sleeve. This makes the sleeve ideally suited for such force-controlled pressing processes using a mandrel, particularly because shearing of the mandrel towards an edge of the sleeve is prevented.

[0022] The sleeve can preferably be designed to be connected to aluminum pipes. In particular, the possibility of precisely centering the crimp point eliminates the need for a second crimp or connection point in the longitudinal direction of the receiving section, allowing the sleeve to be shorter in the longitudinal direction and thus requiring less installation space.

[0023] The at least one positioning aid can be of a particularly simple design if it consists of at least one recess with a square, circular, or triangular cross-section, the cross-section tapering with increasing depth or remaining constant. The positioning aid can also be implemented as a local perforation or granulation that can frictionally and / or positively lock the tip of the press mandrel in place. The recess can have a conical, pyramidal, or conical shape, pointing towards the volume of the receiving section.

[0024] According to a further embodiment, the at least one positioning aid is designed as a single-stage or multi-stage recess. The corresponding stages of the recess have different depths, and the individual stages can be symmetrically, in particular coaxially, or asymmetrically shaped. This measure allows for a positioning aid that is particularly precisely adapted to the tip of the press mandrel. This simplifies the positioning of the press mandrel on the positioning aid and improves the guidance of the press mandrel by the positioning aid.

[0025] The at least one positioning aid can additionally be used as an inspection window or viewing window for the volume of the receiving section if the at least one positioning aid, designed as a recess, projects at least partially through a wall of the receiving section. The section projecting through the wall can be used to check whether the conductor section has been inserted sufficiently far into the volume to ensure an optimal connection through the pressing action. The section projecting through the wall can be designed as a through-hole arranged at least partially symmetrically or asymmetrically. Preferably, a pressing mandrel for this purpose can have a centering section or positioning section that projects into the through-hole and a pressing section that can act on the outer surface of the wall material.The positioning section is therefore spaced apart from at least one pressing section.

[0026] In another embodiment, the receiving section is tubular with a round, oval, asymmetrically shaped, or polygonal cross-section. Preferably, the receiving section has a volume for receiving the stripped conductor section, which is at least partially bounded by the wall. This allows the sleeve to be shaped in a particularly versatile manner. The connecting section of the sleeve can be configured to form a screw connection, a clamp connection, a plug connection, or the like.

[0027] Despite requiring multiple pressing operations, the sleeve can be subject to particularly low deformation if at least two positioning aids are arranged on opposite sides of the receiving section, with at least two positioning aids spaced apart from each other along an elongated extension of the receiving section. The at least two positioning aids can be arranged at an angle of 180° relative to each other. Alternatively, several positioning aids, pivoted relative to each other by, for example, 120°, 90°, or 60°, can be incorporated into the receiving section.

[0028] In particular, the receiving section can have a variety of possible positioning aids along a single position in the longitudinal direction or along several spaced-apart positions along the longitudinal direction, which can be used selectively. It is not necessary to use all positioning aids; for example, one positioning aid can be used to apply pressure.

[0029] Accordingly, in an advantageous embodiment, the connection or pressing between the conductor section and the receiving section can be formed at several positions along an elongated extension of the receiving section to create a particularly strong connection with optimized contact resistance.

[0030] According to a further embodiment, to form the connection between the conductor section and the receiving section, the tip of the crimping mandrel is successively positioned at several locations along the elongated length of the receiving section against multiple positioning aids arranged alternately on opposite sides along the elongated length of the receiving section, and then pushed through the positioning aid into the receiving section. This allows the crimps made by the crimping mandrel to be applied with particular precision and reduces the risk of crimping too far towards the open end of the receiving section.

[0031] The insertion of multiple crimps or connections can be implemented in a particularly versatile way if, in order to position the tip of the crimping mandrel against several positioning aids, the crimping tool and / or the conductor section connected to the receiving section of the sleeve are moved and / or rotated relative to each other.

[0032] According to a further embodiment, the connection between the conductor section and the receiving section is designed such that an uncrimped, edge-side minimum distance of 3 to 20 mm, including 3 mm and 20 mm, is established. This measure ensures that sufficient material is present at the edge and prevents shearing of parts of the conductor section. Brief description of the drawings

[0033] Several embodiments of the invention are explained in more detail below with reference to the drawings. The drawings show: Fig. 1 a schematic top view of a sleeve designed as a cable lug according to an embodiment of the invention, Fig. 2 a schematic top view of the sleeve made of Fig. 1 with an integrated connection between a conductor section and a receiving section of the sleeve, Fig. 3 a perspective view of a pressing tool with an inserted sleeve according to a further embodiment of the invention, Fig. 4 a perspective view of a pressing tool with a sleeve aligned by a positioning aid, and Figs. 5, 6 perspective views of a sleeve made of Fig. 3 with two connections inserted between a conductor section and a receiving section of the sleeve. Preferred embodiments of the invention

[0034] In the Fig. 1Figure 1 shows a schematic top view of a sleeve 10 designed as a cable lug according to an embodiment of the invention. The sleeve 10 is manufactured in one piece from an electrically conductive material, which in the illustrated embodiment is an aluminum alloy. Thus, the connecting section 11 and the receiving section 12 are electrically connected to each other.

[0035] In the illustrated embodiment, no insulation or insulating sheath is present; however, depending on the design of the sleeve, appropriate insulation (not shown) may be provided.

[0036] The sleeve 10 has a connecting section 11 and a receiving section 12 for receiving at least one stripped conductor section 21 of a Fig. 2 shown ladder 20 on.

[0037] The connecting section 11 is designed to form a screw connection. For this purpose, the connecting section 11 is designed in the form of a screw eye and has a through-hole 13 for inserting a screw or threaded rod (not shown).

[0038] The receiving section 12 is designed as a tubular section with a substantially circular cross-section. In particular, the receiving section 12 is elongated along a longitudinal direction L. A circumferential wall 14 of the receiving section 12 defines a volume 15 into which the conductor section 21 can be inserted at its end.

[0039] On the outer side of the receiving section 12, a positioning aid 30 is arranged in the wall 14 of the receiving section 12. The positioning aid 30 is designed as a recess and has two steps 31, 32 of different depths. In particular, a Fig. 3The press mandrel 110 of a press tool 100 shown protrudes positively into the positioning aid 30 at its end.

[0040] A first stage 31 of the positioning aid 30 has a shallower depth than a second stage 32. The first stage 31 is arranged coaxially with the second stage 32 and runs symmetrically around the second stage 32.

[0041] The Fig. 2 shows a schematic top view of the sleeve 10 made of Fig. 1with an inserted connection 40 between the stripped conductor section 21 and the receiving section 12 of the sleeve 10. The stripped conductor section 21 consists of a multitude of thin aluminum wires that are stranded or braided into a bundle. Alternatively, the conductor section 21 can be designed as a solid conductor, a multi-stranded round or sector conductor, and the like. Furthermore, the stripped conductor section 21 can consist of an electrically conductive material, such as copper, aluminum, or an electrically conductive alloy. The Figs. 2 to 6 to illustrate a method for connecting a conductor 20 to an electrically conductive sleeve 10.

[0042] Into the Fig. 2In the illustrated sleeve 10, a connection 40 was inserted into the receiving section 12. The connection 40 has a pattern of the press mandrel 110, which is conically shaped with a plurality of mandrel steps 111. In the illustrated embodiment, only one connection 40 is inserted into the receiving section 12. Due to the precisely centered insertion of the connection 40 by means of plastic deformation of the receiving section 12, this single connection 40 is sufficient to reliably connect the aluminum conductor section 21 to the sleeve 10 in an electrically conductive manner.

[0043] The Fig. 3 Figure 1 shows a perspective view of a pressing tool 100 with an inserted sleeve 10 according to a further embodiment of the invention. In contrast to the one in Fig. 1The electrically conductive sleeve 10 shown here has an extended receiving section 12 in which two connections 40, 41 can be inserted by plastic deformation. The inserted connections 40, 41 are in Fig. 5 and in Fig. 6 illustrated.

[0044] In particular, in Fig. 3 A pressing tool 100, designed as a manually operated pressing jaw, is shown, into which a sleeve 10 is inserted. The sleeve 10 is inserted in a tool section 120 provided for this purpose, which is located between a support 130 and the pressing mandrel 110. The receiving section 12 can thus be pressed between the support 130 and the pressing mandrel 110.

[0045] The sleeve 10 can be rotated and moved along the longitudinal direction L within the inserted tool section 120, making precise positioning of the connection 40 on the circumference of the receiving section 12 impossible. The integrated positioning aid 30 allows the intended position for plastic deformation by the press mandrel 110 to be precisely defined. In particular, the positioning aid 30 allows a tip 112 of the press mandrel 110 to engage in the corresponding recess of the positioning aid 30. This results in optimal alignment between the abutment 130, the sleeve 10, and the press mandrel 110. A correspondingly aligned sleeve 10 is in the Fig. 4 shown.

[0046] The Fig. 4The press tool 100 is illustrated in a perspective view with the sleeve 10 aligned by the positioning aid 30. The tip 112 of the press mandrel 110 protrudes into the positioning aid 30 and is positively locked.

[0047] To form a connection 40 between the conductor section 21 and the receiving section 12 of the sleeve 10, the press mandrel 110 is pushed through the positioning aid 30 or transversely to the longitudinal direction L into the receiving section 12.

[0048] The receiving section 12 is supported on one side opposite the positioning aid 30 by the abutment 130 of the pressing tool 100 during the pressing process.

[0049] After pressing the receiving section 12 into the positioning aid 30, the press mandrel 110 is spaced apart from the sleeve. A mechanical and electrically conductive connection 40 is already formed between the conductor section 21 and the sleeve 10.

[0050] In a further step, a second connection 41 can be introduced into the receiving section 12. For this purpose, a second positioning aid 33 can be provided to form the second connection 41 between the conductor section 21 and the receiving section 12 at a further or second position along the elongated extension of the receiving section 12.

[0051] The second positioning aid 33 is spaced longitudinally L apart from the first positioning aid 30. Furthermore, the first positioning aid 30 is offset by 180° along the longitudinal direction L relative to the second positioning aid 33, so that the press mandrel 110 can be positively engaged on opposite sides of the sleeve 10 to form electrically conductive connections 40, 41 by means of plastic deformation.

[0052] Thus, the tip 112 of the press mandrel 110 is successively placed on several positioning aids 30, 33 arranged alternately on opposite sides along the elongated extension of the receiving section 12 and pushed through the corresponding positioning aid 30, 33 into the receiving section 12 transversely to the longitudinal direction L.

[0053] In the Fig. 5 and the Fig. 6 are perspective views of a sleeve 10 made of Fig. 3The figure shows two connections 40, 41 inserted between a conductor section 21 and the receiving section 12 of the sleeve 10. These represent a result of the method according to the invention. The two connections 40, 41 are shown on two opposite sides 16, 17 of the receiving section 12.

[0054] In particular, a first connection 40 is inserted into a first side 16 and a second connection 41 into a second side 17 of the receiving section 12. Furthermore, deformation marks 50, 51 of the abutment 130 are visible in the receiving section 12. These corresponding deformation marks 50, 51 are formed on opposite sides 16, 17 of the inserted connections 40, 41 due to the manufacturing process. Reference symbol list

[0055] 100 Pressing tool / Pressing pliers 110 Pressing mandrel 111 Mandrel steps 112 Tip of the pressing mandrel 120 Tool section for holding sleeves 130 Abutment 10 Electrically conductive sleeve / end sleeve 11 Connection section 12 Receiving section 13 Through hole 14 Circumferential wall of the receiving section 15 Volume of the receiving section 16 First side of the receiving section 17 Second side of the receiving section 20 conductors / cable 21 stripped conductor section 30 First positioning aid 31 First stage of the positioning aid 32 Second stage of the positioning aid 33 Second positioning aid 40 first connection 41 second connection 50 Deformation marks of the first connection 51 Deformation marks of the second connection Longitudinal direction

Claims

1. Electrically conductive sleeve (10) designed as a press sleeve, having at least one connecting section (11) and at least one receiving section (12) for receiving at least one stripped conductor section (21) of an electrically conductive conductor (20), wherein the connecting section (11) and the receiving section (12) are electrically conductively formed with one another, characterized in that the receiving section (12) has at least one positioning aid (30) for positioning a mandrel (110) of a pressing tool (100) on the outside of the receiving section (12), wherein the at least one positioning aid (30) is designed as at least one recess in the receiving section (12).

2. Sleeve according to claim 1, wherein the at least one positioning aid (30) designed as at least one recess has a square, circular or triangular cross-section, wherein the cross-section tapers or is constant with increasing depth.

3. Sleeve according to claim 1 or 2, wherein the at least one positioning aid (30) is designed as a single-stage or multi-stage recess, wherein the stages (31, 32) of the recess have a different depth, wherein the respective stages (31, 32) are symmetrical, in particular coaxial, or asymmetrical in shape.

4. Sleeve according to one of claims 1 to 3, wherein the at least one positioning aid (30) designed as a recess projects at least in some areas through a wall (14) of the receiving section (12).

5. Sleeve according to one of claims 1 to 4, wherein the receiving section (12) is formed tubular with a round or oval or asymmetrically shaped or polygonal cross-section and has a volume (15) for receiving the stripped conductor section (21), which is limited at least in part by the wall (14).

6. Sleeve according to one of claims 1 to 5, wherein at least two positioning aids (30, 33) are arranged on opposite sides (16, 17) of the receiving section (12), wherein at least two positioning aids (30, 33) are spaced apart from each other along an elongated extension of the receiving section (12).

7. Method for connecting a conductor (20) to an electrically conductive sleeve (10) according to claim 1, wherein a stripped conductor section (21) of the conductor (20) is arranged in a volume (15) of a receiving section (12) of the sleeve (10), wherein the sleeve (10) is positioned with the conductor section (21) arranged in the receiving section (12) such that a tip (112) of a mandrel (110) of a pressing tool (100) interacts in a form-fitting manner with a positioning aid (30) arranged on the outside of the receiving section (12) in the form of a recess in the receiving section (12), wherein the mandrel (110) deforms a volume (15) of the receiving section (12) with the aid of the positioning aid (30) to form a connection (40) between the conductor section (21) and the receiving section (12), wherein the receiving section (12) is supported on a side (17) opposite the positioning aid (30) by an abutment (130) of the pressing tool (100).

8. Method according to claim 7, wherein the connection (40) between the conductor section (21) and the receiving section (12) is formed at several positions along an elongated extension of the receiving section (12).

9. Method according to claim 8, wherein, in order to form the connection (40) between the conductor section (21) and the receiving section (12) at several positions along the elongated extension of the receiving section (12), the tip (112) of the mandrel (110) is placed one after the other on positioning aids (30, 33) arranged at several positions along the elongated extension of the receiving section (12) alternately on opposite sides (16, 17) and is pushed through the positioning aid (30, 33) transversely to a longitudinal direction (L) into the receiving section (12).

10. Method according to claim 9, wherein, in order to place the tip (112) of the mandrel (110) on several positioning aids (30, 33), the pressing tool (100) and / or the conductor section (21) connected to the receiving section (12) of the sleeve (10) are moved and / or rotated relative to each other.

11. Method according to one of claims 7 to 10, wherein the connection (40, 41) between the conductor section (21) and the receiving section (12) is formed such that an unpressed minimum edge distance of 3 to 20 mm, including 3 mm and 20 mm, is set.