Electrical connection device

Abstract

The invention relates to an electrical connection device comprising at least one terminal block and a lug, said terminal block being configured to receive said lug, said lug is connected to an electric cable (3) having one end. Said terminal block comprises a terminal block body (11) having a hollow cylindrical part, a cap (12) closing one side of the hollow cylindrical part, a conductive connection bar connected to the end of said lug by a fixing element. Said lug comprises a circular cylindrical part configured to enter the hollow cylindrical part of the terminal block. Figure for abstract: Fig. 1

Description

Title of the invention: Electrical connection device Technical field of the invention

[0001] The present invention relates to an electrical connection device. It applies, in particular, in the field of aeronautics linked to the increase in electrical power. Prior art

[0002] The use of standard connectors presents reliability risks: unlocking under vibration, greater heating, etc.

[0003] Conventional lugs and terminals have several defects: lack of sealing, lack of shielding if the cable is shielded, electrical insulation not suitable for high voltage (electrical breakdown in the air or by surface tracking of the insulators), often need for electrical insulation and environmental protection (pollution, humidity, corrosion, etc.).

[0004] Current terminal blocks are composed of insulating blocks comprising several channels formed by studs and nuts.

[0005] Each channel is insulated by a partition made of insulating material to ensure electrical insulation. It is possible to add a cover to each channel, where terminals can be connected. However, this configuration does not guarantee adequate protection of the terminals against environmental elements such as corrosion.

[0006] The conventional terminal provides the electrical connection between a cable and another terminal, a structure or a bus bar. However, this approach has the disadvantage of not providing electrical insulation. To overcome this, it is possible to add an insulating sleeve over the terminal, thus providing electrical insulation and protection against environmental elements such as corrosion.

[0007] These solutions include various drawbacks: - no possibility of (electromagnetic) shielding or shielding recovery on the cables; - no waterproofing, no protection against the environment (risk of corrosion, etc.); - No protection of people; - not very suitable for high voltage due to the risk of electrical arcing between the different tracks by bypassing the insulating partitions. Presentation of the invention

[0008] The present invention aims to remedy these drawbacks with a completely innovative approach.

[0009] More specifically, the invention aims to provide a connection technique to avoid torsional stresses in the electrical cable.

[0010] In particular, an objective of the invention is to provide such a technique allowing electrical continuity.

[0011] These objectives, as well as others which will appear subsequently, are achieved, according to a first aspect, using an electrical connection device comprising at least one terminal block and one lug, said terminal block being configured to receive said lug, said lug is connected to an electrical cable comprising one end and remarkable in that: - said terminal block comprises a terminal block body having a hollow cylindrical part, a cap closing one side of the hollow cylindrical part, a conductive connection bar connected to the end of said terminal by a fixing element; - said terminal comprises a circular cylindrical part configured to enter the hollow cylindrical part of the terminal block.

[0012] The present invention makes it possible to combine the advantages of a terminal block and the advantages of a connector: secure screw connection, no risk of unlocking under vibration, less heating than a connector thanks to the good electrical contact provided by the terminal, addition of sealing, electrical insulation making it possible to increase the voltage resistance (partial discharges, creepage lines and distances in the air).

[0013] Thanks to these provisions, the device consisting of a terminal block and a lug allows electrical continuity between the cable (connected to the lug) and another element (cable, bus bar) connected to a connection bar present in the terminal block.

[0014] The device allows for a terminal to be orientable 360° around its axis, in order to avoid torsional stresses in the cable.

[0015] The device allowing electrical insulation between a terminal and a connection bar, having specific shapes on the insulating elements in order to allow the installation of a tightening torque between a screw and the terminal.

[0016] The invention is advantageously implemented according to the embodiments and variants set out below, which are to be considered individually or according to any technically effective combination.

[0017] In one embodiment, the fastening element is a screw configured to be screwed into the end of the terminal in a thread, or the terminal has a thread at its end and said fastening element is a nut configured to screw onto the thread of said terminal.

[0018] In one embodiment the fastening element is a quick-fastening device, said quick-fastening device is a quick-tightening lever or a quarter-turn fastening.

[0019] In one embodiment, the terminal body, the cap and the terminal body comprise a metal layer.

[0020] The metal layer is produced selectively on the surfaces of the parts, with the aim of maintaining the electrical insulation function thereof and maintaining sufficient insulation distances between the live elements and the metal layers.

[0021] In one embodiment, a ground ring is compressed between the metal layer of the plug body and the metal layer of the receptacle body configured to provide electrical continuity between each metal layer.

[0022] In one embodiment, the terminal comprises a terminal body and a contact, said contact is inserted into the terminal body and is held in position by a rotation locking element.

[0023] In one embodiment, the rotation locking element comprises a terminal imprint at one end of the terminal body and an imprint of complementary shape to the terminal imprint, said complementary shape imprint belonging to said contact.

[0024] The device has a metallized terminal body and plug body and allows electromagnetic shielding of the assembly, with shielding recovery on the cable, and protection against electrical breakdown and partial discharge phenomena.

[0025] The device provides sealing between the cable and the terminal body, between the terminal body and the terminal body, between the terminal body and the structure or partition.

[0026] In one embodiment, the electrical cable comprises a conductor made of a copper or aluminum alloy which is crimped into a crimping barrel of the terminal body.

[0027] In one embodiment, on the outside of the lug body are flats.

[0028] The flats allow the rotation of the terminal body to be blocked using a flat spanner.

[0029] In one embodiment, said cap is screwed or clipped to the body of the terminal block.

[0030] In one embodiment, the terminal block body is comprised of two or more channels allowing two or more pods to be accommodated.

[0031] According to one embodiment, the terminal block is configured to receive several lugs. Brief description of the figures

[0032] Other advantages, aims and characteristics of the present invention emerge from the following description given, for explanatory and in no way limiting purposes, with reference to the appended drawings, in which:

[0033] [Fig.l] represents a perspective view before the connection of a terminal with a terminal block;

[0034] [Fig.2] shows an exploded view of the terminal;

[0035] [Fig.3] represents a sectional view of the terminal block;

[0036] [Fig.4] represents a sectional view of the lug;

[0037] [Fig.5] represents a section of the interior of the assembly between the terminal block and the pod.

[0038] In the description and the claims, to clarify the elements, the terminology longitudinal, transverse and vertical will be adopted without limitation with reference to the trihedron X, Y, Z indicated in the figures. Description of the embodiments

[0039] [Fig.l] shows a perspective view before connecting a terminal to a terminal block.

[0040] This figure is divided into a first part and a second part.

[0041] The first part includes a terminal block.

[0042] A terminal block is a device used to connect electrical wires to each other or to connect them to electrical equipment.

[0043] According to an exemplary embodiment, the terminal block comprises a body 11 having a hollow cylindrical part, a plug closing one side of the hollow cylindrical part, and a conductive connection bar.

[0044] The body 11 comprises a support structure positioned below the hollow cylindrical part. This is a structure or partition comprising holes 1a to be fixed by screws. The holes 1a may be circular or oblong for a bolted or tapped assembly.

[0045] The second part corresponds to a pod.

[0046] A terminal 2 is an electrical connection device used to join an electrical cable 3, an electrical wire to a device, a component or another wire.

[0047] The terminal facilitates the connection of the electrical cables 3 by creating a secure and reliable interface.

[0048] According to one example, the terminal comprises a circular cylindrical part configured to enter the hollow cylindrical part of the terminal block.

[0049] The conductive connecting bar is connected to the end of said terminal by a fixing element.

[0050] To assist in assembly, the terminal 2 has flats around the perimeter of the terminal 2.

[0051] The fastening element is a screw configured to be screwed into the end of the terminal in a thread.

[0052] Tapping is the process of creating threads inside a previously drilled hole. This allows a screw, bolt, or other threaded element to be screwed into the hole.

[0053] According to a variant, the terminal has a thread at its end and said fixing element is a nut configured to screw onto the thread of said terminal.

[0054] The terminal comprises a connection with an electric cable 3 which has one end.

[0055] According to an exemplary embodiment, the lug comprises a harness making it possible to avoid torsional stresses in the cable during installation.

[0056] The connection between the terminal block and the lug provides resistance to vibrations, better electrical contact, and avoids the phenomenon of “fretting-corrosion” (for contact corrosion in French).

[0057] The phenomenon of "fretting corrosion" is a type of corrosion that occurs under conditions of oscillating friction or micro-movements between two surfaces in contact. This phenomenon generally occurs when slight vibrations, oscillations or repetitive movements are present between the surfaces, even on a microscopic scale.

[0058] The main characteristics of the assembly of the terminal 2 in the terminal block 1 are an adaptation of the connection means to high power (voltage or current), good resistance to vibrations and improvement of the electrical contact. This assembly avoids contact corrosion phenomena and is waterproof with 360° electromagnetic shielding and shielding recovery on the cable.

[0059] The harness is 360° rotatable to avoid torsional stresses in the cable during installation.

[0060] Naturally, the invention is described in the above by way of example. It is understood that a person skilled in the art is able to carry out different variant embodiments of the invention without departing from the scope of the invention.

[0061] [Fig.2] shows an exploded view of the terminal.

[0062] When connecting between the terminal block and the lug, the screw 15 allows tightening between the contact 22 and the connecting bar. To allow the tightening torque to be installed, rotation between contact 22 and the terminal body 21 must be blocked. To do this, flats 22a are present on contact 22.

[0063] An imprint 21b, of a shape complementary to that of the flats 22a, is present in the terminal body 21. This makes it possible to block the rotation of the contact 22 once that it is installed in the terminal body. In other words: the terminal body 21 has at its end a terminal imprint 21b and the contact 22 has an imprint having flats 22a, said imprint is of a shape complementary to the terminal imprint 21b.

[0064] Flats 21c are present on the terminal body at the exterior level. These are used to block the rotation of the terminal body 21 by using a flat wrench.

[0065] In one embodiment, the flats and indentations are replaced by hexagonal shapes, or by keys.

[0066] When the wiring is completed and the contact is installed in the terminal body 21, an O-ring 26 is added in the O-ring groove 22b of the contact 22. This seal ensures the retention of the contact 22 in the terminal body 21.

[0067] In one embodiment, the seal is replaced by an axial retention element (example: elastic ring, snap ring).

[0068] [Fig.3] shows a sectional view of the terminal block.

[0069] The terminal block 1 is constructed from an electrically insulating material. This electrically insulating material allows electrical insulation, protection of components, positioning of components, fixing to a structure or a partition.

[0070] The terminal block body 1 is metallized by a metal layer 12a and provides 360° shielding while ensuring electrical insulation and avoiding electrical breakdown between the metal layer and the electrical conductors.

[0071] A contact surface between the metal layer of the plug 12a and that of the terminal body 11a allows the electrical continuity of the shielding. The plug has a groove in which a seal 18 is mounted. This seal ensures sealing and also allows the leakage lines between the electrical conductors and the metallization to be cut in order to avoid electrical breakdown.

[0072] The metal layers 11a of the terminal body, 12a of the cap and 21a of the plug body provide protection against the phenomenon of partial discharges.

[0073] The connecting bar 13 allows an electrical connection with the terminal thanks to the screw 15.

[0074] The connecting bar 13 is conductive according to one example it is made of copper, brass, etc. and possibly with surface treatment: gold, silver, nickel, etc.) which allows the electrical connection to the terminal

[0075] The connecting bar 13 is made integral with the body of the terminal block 11 by means of a stop segment 19. This connecting bar 13 is connected to a cable (crimped onto a terminal) or a bus bar at its external part by means of the smooth hole 13a.

[0076] This smooth hole can be replaced by a brazed or welded section, or by a crimp barrel for direct connection to the cable.

[0077] In addition, a seal 18 provides sealing between the connecting bar 13 and the body of the terminal block 11. The seal 18 is an O-ring.

[0078] Once the screw is installed on the terminal, an elastic washer 16 brakes the screw to prevent it from loosening. According to another example, a system other than an elastic washer is used. The aim is to prevent loosening due to vibrations, for example.

[0079] A support washer 17 is placed between the screw 15 and the support surface of the connecting bar 13.

[0080] When the base is fixed to a partition, the use of a partition seal 14 made of elastomeric material makes it possible to obtain a seal. The compression is made between the base and the partition, the partition seal is compressed.

[0081] The partition joint 14 facilitates the extension of the electrical path distances (creepage lines) between the connection bar 13 and the structure or the partition.

[0082] To allow the installation of the screw, a cap 12 is unscrewed and screwed back on once the screw 15 is installed.

[0083] According to one embodiment, electromagnetic shielding is not required, so the metal layer on cap 12 and terminal body 11 is not necessary.

[0084] In one embodiment, the metallization layer(s) are replaced by a metal cover.

[0085] In one embodiment, the screw is attached to the cap.

[0086] [Fig.4] shows a sectional view of the lug.

[0087] The terminal body 21 made of insulating materials allows positioning of the contact 22. The terminal body 21 allows a tightening torque while maintaining electrical insulation using the external metal layer 21a, shown in bold in the figure. The 360° shielding prevents breakdown between the conductor and the metal layer.

[0088] Contact 22 is conductive (copper, brass, nickel, etc. with possible surface treatment), and has at its end a threaded hole for the installation of the screw and a crimping barrel for connection to the cable, to ensure electrical continuity.

[0089] A grommet 23 is used to cut the creepage lines and prevent electrical breakdown between the conductors and the shielding. According to one example, the grommet 23 is made of elastomeric material. The grommet 23 provides a seal between the cable and the terminal body.

[0090] A ground ring 24 is put in place to achieve electrical continuity of shielding between the metal layer of the terminal body 21a and that of the terminal body 11a.

[0091] To ensure sealing between the terminal body 21 and the terminal body, an O-ring 25 is installed.

[0092] The cable is made up of different elements presented below:

[0093] The conductor 31 is made of a copper or aluminum alloy which is crimped into the crimping barrel of the body of the terminal 21.

[0094] An electrical insulator 32 is used to ensure the electrical insulation of the cable. This electrical insulator 32 ensures sealing by compressing the lips of the grommet 23.

[0095] A copper shielding braid 33 is electrically connected to the metal layer of the plug body by means of a clamp 34 in order to ensure the electrical continuity of the shielding.

[0096] According to one embodiment, a sleeve made of an elastomer part is added to make the shielding braid watertight. According to another embodiment, it is a heat-shrinkable sheath 35.

[0097] In a groove of the contact 22, an O-ring 26 is added to the terminal end of the wiring. The retention of the contact in the terminal body 21 is ensured by this retention O-ring 26.

[0098] According to one embodiment, the ground ring and the O-ring 26 are not present in the terminal body, but in the terminal body.

[0099] [Fig.5] shows a section of the interior of the assembly between the terminal block and the lug.

[0100] Regarding sealing, an O-ring 18 is positioned in the terminal body 11 and ensures sealing between the terminal body 11 and the connecting bar 13.

[0101] Another O-ring 18 is positioned in the plug 12 and ensures the sealing of the assembly once the plug 12 is completely screwed into the terminal body 11.

[0102] Another O-ring 18 is positioned in the terminal body 11 and ensures sealing between the terminal body 11 and the terminal body 21, once the harness (terminal 2 and electrical cable 3) is connected.

[0103] An O-ring 25 is positioned on the terminal body 11 and ensures sealing between the terminal body 11 and the terminal body 25. This sealing is done in addition to the sealing made by the O-ring 18 positioned in the terminal body 11, and makes it possible to protect the ground ring 24.

[0104] A partition seal 14 is installed in the terminal block body 11 and allows, when the terminal block is fixed to a structure or a partition, to seal the structure or the partition.

[0105] A grommet 23 provides sealing between the electric cable 3 and the terminal body 21 by means of lips compressing, on the inside, on the insulation of the cable 32, on the outside in a bore present in the terminal body 21.

[0106] Concerning the safety of users, once the harness (terminal 2 and electric cable 3) is connected in the terminal block body 11 and the cap 12 screwed, and the assembly fixed to a partition, it is impossible to insert your finger inside the assembly and touch live conductors.

[0107] Regarding the transmission of electrical power, the use of the screw 15 allows a plane-plane contact between the connecting bar 13 and the contact 22 with a high clamping force and contact pressure.

[0108] This ensures reliable electrical contact with low electrical contact resistance (low heating). This helps to avoid the phenomenon of fretting-corrosion (wear of the contact surface by repeated micro-movements) by preventing any relative movement between the contacting surfaces.

[0109] One of the disadvantages of conventional lugs is that when they are connected (by bolted assembly for example), the rotation of the cable is imposed and this can generate mechanical stresses in the cable.

[0110] In the present invention, the harness (lug 2 and electric cable 3) can be freely rotated around the longitudinal axis X before tightening the screw 15. This makes it possible to avoid generating mechanical stresses in the cable during installation.

[0111] The electrical conductor 31 of the electrical cable 3 is connected to the contact 22 by crimping. In one embodiment: it is possible to have brazing, welding.

[0112] On the lower side, a cable or a bus bar can be connected to the connection bar 13, by bolted assembly (thanks to the flat and the smooth hole), alternatively by crimping, brazing or welding.

[0113] This assembly allows 360° electromagnetic shielding and shielding recovery on the cable.

[0114] The shielding braid 33 of the electric cable 3 is clamped over the metal layer of the plug body 21a by means of a clamp 34. This guarantees electrical continuity between the shielding braid 33 and the plug body 21.

[0115] A ground ring 24 is compressed between the metal layer of the plug body 21a and that of the base body 11a in order to ensure electrical continuity between the two metal layers.

[0116] When the terminal body 11 is fixed to a structure or a partition, its metal layer 11a is in contact with the structure or the partition, which allows the continuity of shielding between the two.

[0117] When the plug 12 is screwed into the base body 11, the metal layer of the plug 12a and that of the base body 11a are in contact in order to ensure the continuity of shielding between the two.

[0118] This terminal and terminal assembly is suitable for high voltage. There is a reduction in the risk of electrical breakdown in the air or by surface tracking of the insulators.

[0119] On the upper side, all the leakage lines are cut by elastomeric parts. The O-ring 18 in the plug 12 allows the leakage lines between the live conductors and the metal layers 11a, 12a of the terminal body 11 and the cap 12.

[0120] The O-ring 18 in the terminal body 11 makes it possible to cut the leakage lines between the live conductors and the metal layer 21a of the plug body 21.

[0121] The grommet (23) makes it possible to cut the leakage lines between the live conductors and the shielding braid 33 of the electric cable 3 and the metal layer 21a of the plug body 21.

[0122] On the lower side, the creepage lines and the distances in the air between the conductors and the structure are lengthened by the presence of the partition joint 14.

[0123] Thanks to the surface metallization of the insulators and the metal layers 11a, 12a, 21a, the voltage at which partial discharges of the assembly occur is increased.

[0124] Indeed, in a “classic” design, a metal casing is added over the insulation. Layers of air are therefore added between the metal casing and the insulation; these areas are at risk of partial discharges.

[0125] In the present invention, metallization directly on the insulators makes it possible to avoid the appearance of air layers and therefore to reduce the risk of the appearance of partial discharges.

[0126] It is emphasized that all features, as they emerge for a person skilled in the art from the present description, the drawings and the attached features, even if concretely they have only been described in relation to other determined features, both individually and in any combinations, can be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless. List of reference signs

[0127] [Tableauxl] References Designations 1 terminal block 1a holes 11 terminal block body 11a metal layer of the terminal block body 12 cap 12a metal layer of the cap 13 connection bar 13a smooth hole 14 bulkhead gasket 15 screw 16 spring washer 17 thrust washer 18 gasket 19 snap ring 2 terminal 21 terminal body 21a terminal metal layer 21b indentation 21c terminal body flats 22 contact 22a contact flats 23 grommet 24 ground ring 25 O-ring 26 retention O-ring 3 electrical cable 31 conductor 32 electrical insulation 33 shielding braid 34 cable tie 35 heat shrink tubing

Claims

Claims

1. Electrical connection device comprising at least one terminal block and one lug, said terminal block being configured to receive said lug, said lug is connected to an electric cable (3) having one end and characterized in that: - said terminal block comprises a terminal block body (11) having a hollow cylindrical part, a cap (12) closing one side of the hollow cylindrical part, a conductive connection bar connected to the end of said lug by a fixing element; - said lug comprises a circular cylindrical part configured to enter the hollow cylindrical part of the terminal block.

2. Device according to claim 1, in which the fixing element is a screw (15) configured to be screwed into the end of the terminal in a thread, or the terminal has a thread at its end and said fixing element is a nut configured to screw onto the thread of said terminal.

3. A device according to claim 1, wherein the fastening element is a quick-release device, said quick-release device is a quick-release lever or a quarter-turn fastener.

4. A device according to claim 1, wherein the terminal body (11), the cap (12) and the terminal body (21) comprise a metal layer.

5. Device according to claim 4, wherein a ground ring (24) is compressed between the metal layer (21a) of the plug body (21) and the metal layer (11a) of the base body (11) configured to ensure electrical continuity between each metal layer.

6. A device according to claim 1, wherein the terminal comprises a terminal body (21) and a contact (22), said contact (22) is inserted into the terminal body and is held in position by a rotation locking element.

7. A device according to claim 6, wherein the rotation locking element comprises a terminal imprint (21b) at one end of the terminal body (21) and an imprint (22a) of complementary shape to the terminal imprint (21b), said complementary shape imprint (22a) belonging to said contact (22).

8. Device according to claim 1, in which the electric cable (3) comprises a conductor (31) made of a copper or aluminum alloy which is crimped in a crimping barrel of the body of the terminal (21).

9. A device according to claim 1, wherein on the outside of the terminal body (21) there are flats (21c).

10. Device according to claim 1, wherein said cap (12) is screwed or clipped to the body of the terminal block (11).

Images