EP3525291B1

EP3525291B1 - Electrical terminal assembly

Info

Publication number: EP3525291B1
Application number: EP18155754.7A
Authority: EP
Inventors: Dariuz PALUCH; Konrad T KLOCH; Przemyslaw CIEPKA; Dominik KAWALEC
Original assignee: Aptiv Technologies Ltd
Current assignee: Aptiv Technologies Ltd
Priority date: 2018-02-08
Filing date: 2018-02-08
Publication date: 2023-04-05
Anticipated expiration: 2038-02-08
Also published as: EP3525291A1

Description

TECHNICAL FIELD OF INVENTION

The invention relates to an electrical terminal assembly for use in electrical junction boxes distributing high currents in vehicles.

BACKGROUND OF INVENTION

The number of Advanced Driver Assistance Systems used in vehicles increases continuously. This ADAS require support devices that use high currents while perform their functions controlled by the ADAS controller. The high current is distributed injunction boxes. The junction boxes comprise also high current fuses to protect the wire harness and the electrical devices in case of malfunction. The fuses have blade shaped contacts adapted to be connected to fork shaped electrical contacts. In the past the junction boxes have been equipped with bus bars that had electrical terminals made of a part of and protruding from the bus bar. This design works fine for currents up to 18 Ampere. For higher currents up to 32 Ampere, the contact resistance limits the usability. To overcome this problem the bus bar and the electrical terminals are oversized in known junction boxes. To provide a second electrical terminal parallel to a first one, that additional contacts the blade shaped contact of the fuse is a further solution. But this solutions increase costs, weight and size of the junction boxes.
US 3,748,633 A discloses an electric terminal assembly in accordance with the preamble of claim 1. Fork-shaped electrical contacts are further disclosed in JP S50 49682 U , JP H04 46369 U , FR 1310684 A and GB 1 501 255 A .
Thus, there is the need in the art to provide an electrical terminal assembly for a junction box that provides low electrical resistance as well as good thermal conductivity, thereby only requiring usual insertion forces while connecting the terminal assembly.

SUMMARY OF THE INVENTION

An electrical terminal assembly according to claim 1 solves this object, which becomes apparent upon reading the following description.
The disclosed invention provides an electrical terminal assembly having a fork shaped electrical contact. The fork shaped electrical contact has three flat surfaces for making contact to a blade shaped mating electrical contact that is hold in between the prongs. The flat main contact surface, the flat first support surface and the flat second support surface contact the surfaces of the blade shaped mating electrical contact at the opposite corresponding surfaces. The surfaces are arranged flat on the surface of the blade shaped mating electrical contact, proving a large contact surface. The large contact surface provides low electrical resistance as well as good thermal conductivity, thereby not increasing the insertion force of the electrical terminal assembly.
The flat main contact surface extends a longer distance, along the first prong, than the total distance the flat first support surface and second flat support surface extend along the second prong. This provides a huge, flat contact surface, contacting the flat blade shaped mating electrical contact, while not increasing insertion force of the electrical terminal assembly.
According to a preferred embodiment, the first flat mating contact surface is in contact with the flat main contact surface and the second flat mating contact surface is in contact with the flat first support surface and the flat second support surface, when fully mated. The surfaces are arranged and formed to provide as much contact surface as possible, while not increasing insertion force of the electrical terminal assembly.
Advantageously, the flat main contact surface extends at least half the length of the first prong this provides a huge, flat contact surface, contacting the flat blade shaped mating electrical contact.
Preferably, the width of the first prong is constant along the extension of the flat main contact surface. This design provides constant electrical resistance along the first prong. That prevents hot spots caused by portions with higher electrical resistance.
According to the invention, the second prong comprises a narrowing defined by a cut out located in between the flat first support surface and the flat second support surface, narrowing the width of the second prong perpendicular to the mating axis. The narrowing weakens the second prong on the position. This makes the second prong more flexible using the weaker portion as a flexible hinge, thereby decreasing insertion force of the electrical terminal assembly.
Preferably, the width of the second prong decreases starting from the second flat support surface along the mating axis, towards the base. The decreasing of the width of the second prong goes along with increasing of flexibility of the second prong. This provides decreasing of insertion force of the electrical terminal assembly and flexible support for the flat first support surface and the flat second support surface towards the blade shaped mating electrical contact.
Preferably, the flat main contact surface is parallel to the flat first support surface and is parallel to the flat second support surface, when fully mated to the blade shaped mating electrical contact. The contact surface is at its maximum and the electrical resistance is at its minimum, when the contact surface is parallel to the flat first support surface and is parallel to the flat second support surface, thereby contacting the parallel surfaces of the blade shaped mating electrical contact.
In a preferred embodiment, the flat main contact surface is not parallel to the flat first support surface or/and not parallel to the flat second support surface, when not mated to the blade shaped mating electrical contact. Preferably, the flat first support surface or/and the flat second support surface are sloped towards the first prong, when not mated to the blade shaped mating electrical contact. At least one of the first prong and a second prong is formed inwards the gap, thereby limiting the space between the flat main contact surface and the flat first support surface and the flat second support surface to an amount les the width of the blade shaped mating electrical contact. That enables to provide a pre tension to the flat main contact surface and the flat first support surface and the flat second support surface that pushes the surfaces toward the blade shaped mating electrical contact when mated, thereby having the surfaces parallel.
Advantageously, the blade shaped mating electrical contact comprises a rectangular cross-section. The rectangular cross-section of the blade shaped mating electrical contact provides straight, flat and parallel surfaces to make with the flat main contact surface and the flat first support surface and the flat second support surface.
Preferably, the blade shaped mating electrical contact and the fork shaped electrical contact are made of sheet metal. The blade shaped mating electrical contact and the fork shaped electrical contact can be easy stamped out of a sheet metal that keeps production costs low. The fork shaped electrical contact can be made of the same sheet metal as the bus bar. The bus bar and the fork shaped electrical contact can be made as one part out of a sheet metal. Alternatively, the base of the fork shaped electrical contact can be adapted to be attached to a printed circuit board or to the end of an electrical wire.
In a preferred embodiment, the total area of the main contact surface is at least double the size than the total area of the flat first support surface and the second flat support surface in total. The sizes of the main contact surface and the size of the flat first support surface and size of the second flat support surface are balanced to reach a combination of required electrical resistance and required insertion force.
Advantageously, the first prong is more rigid than the second prong. A more rigid first prong provides a robust support for the main contact surface.
Preferred is an electrical junction box comprising the inventive electrical terminal assembly, wherein the fork shaped electrical contact is defined of a part of an electrical bus bar and wherein the blade shaped mating electrical contact is defined by a contact of a high current fuse. In state of the art, electrical junction boxes electrical contacts defined of a part of an electrical bus bar are widely used. The new designed fork shaped electrical contact can replace the currently used electrical contacts without changes on the housings of the electrical junction boxes.

Description of the preferred embodiments

In the following, the invention is described exemplarily with reference to the enclosed figures, in which

Fig. 1: shows a plane, view to an electrical terminal assembly known in prior art;
Fig. 2: shows a plane, view to an electrical terminal assembly;
Fig. 3: shows a plane, view to a fork shaped electrical contact;
Fig. 4: shows a perspective, view to a fork shaped electrical contact;

Figure 1 shows a plane, view to an electrical terminal assembly 10 known in prior art. The electrical terminal assembly 10 comprises a fork shaped electrical contact 12 having a base 22. A first prong 13 and a second prong 16 extend from a base 22 along a mating axis X. A blade shaped mating electrical contact 20 is arranged in a gap 24 between the first prong 13 and a second prong 16. A first contacting nub 17a and a second contacting nub 17b, spaced from the first contacting nub 17a along the mating axis, protrude from the first prong 13 towards the blade shaped mating electrical contact 20. A third contacting nub 17c protrudes from the second prong 16 towards the blade shaped mating electrical contact 20. The three contacting nubs 17a,b,c contact the blade shaped mating electrical contact 20 with a the ends of the contacting nubs what result in a small contact surface between the blade shaped mating electrical contact 20 and the fork shaped electrical contact 12.
Figure 2 shows a plane, view to an electrical terminal assembly 100. The electrical terminal assembly 100 comprising a fork shaped electrical contact 120 having a first prong 130 and a second prong 160, extending along a mating axis X, from a base 122 of the fork shaped electrical contact 120. The first prong 130 and a second prong 160 are spaced apart by a gap 124 disposed there between. The gap 124 is configured to receive a blade shaped mating electrical contact 200 that mechanically and electrically communicates with the first prong 130 and the second prong 160. The blade shaped mating electrical contact 200 comprises a first flat mating contact surface 220 arranged along the mating axis X and a second flat mating contact surface 230 arranged, parallel to the first flat mating contact surface 220. The first prong 130 comprises a flat main contact surface 132 extending along the mating axis X and arranged opposite to the second prong 160 and wherein the second prong 160 comprises a flat first support surface 162 and a flat second support surface 164 arranged opposite to the first prong 130. The blade shaped mating electrical contact 200 is clamped between the flat main contact surface 132 and the flat first support surface 162 and the flat second support surface 164. The first flat mating contact surface 220 is in contact with the flat main contact surface 132 and the second flat mating contact surface 230 is in contact with the flat first support surface 162 and the flat second support surface 164. The flat main contact surface 132 is parallel to the flat first support surface 162 and is also parallel to the flat second support surface 164.
Figure 3 shows a plane, view to a fork shaped electrical contact 120. The flat main contact surface 132 extends a longer distance, along the first prong 130, than the total distance, the flat first support surface 162 and second flat support surface 164 extend along the second prong 160. The flat main contact surface 132 extends at least half the length of the first prong 130. The width of the first prong 130 is constant along the extension of the flat main contact surface 132. The second prong 160 comprises a narrowing defined by a cut out 166 located in between the flat first support surface 162 and flat second support surface 164, narrowing the width of the second prong 160 perpendicular to the mating axis X. The width of the second prong 160 decreases starting from the second flat support surface 164 along the mating axis, towards the base 122. The flat main contact surface 132 is not parallel to the flat first support surface 162 and also not parallel to the flat second support surface 164. The flat first support surface 162 and the flat second support surface 164 are sloped towards the first prong 130.
Figure 4 shows a perspective, view to a fork shaped electrical contact 120. The total area of the main contact surface 132 is at least double the size than the total area of the flat first support surface 162 and the second flat support surface 164 in total.

Claims

An electrical terminal assembly (100) comprising a blade shaped electrical contact (200) and a fork shaped electrical contact (120) having a first prong (130) and a second prong (160) extending along a mating axis (X) from a base (122) of the fork shaped electrical contact (120), spaced apart by a gap (124) disposed there between, wherein the gap (124) is configured to receive the blade shaped mating electrical contact (200) that mechanically and electrically communicates with the first prong (130) and the second prong (160), when the blade shaped mating electrical contact (200) is fully mated, wherein the blade shaped mating electrical contact (200) comprises a first flat mating contact surface (220) arranged along the mating axis (X) and a second flat mating contact surface (230) arranged parallel to the first flat mating contact surface (220), wherein the first prong (130) comprises a flat main contact surface (132) extending along the mating axis (X) and arranged opposite to the second prong (160) and wherein the second prong (160) comprises a flat first support surface (162) and a flat second support surface (164) arranged opposite to the first prong (130), wherein the blade shaped mating electrical contact (200) is clamped between the flat main contact surface (132) and the flat first support surface (162) and the flat second support surface (164)), when fully mated thereby providing electrical connection,
wherein the second prong (160) comprises a narrowing defined by a cut out (166) located in between the flat first support surface (162) and the flat second support surface (164), narrowing the width of the second prong (160) perpendicular to the mating axis (X),

characterized in that

the flat main contact surface (132) extends a longer distance along the first prong (130) than the total distance the flat first support surface (162) and second flat support surface (164) extend along the second prong (160).
An electrical terminal assembly (100) according to claim 1, wherein the first flat mating contact surface (220) is in contact with the flat main contact surface (132) and the second flat mating contact surface (230) is in contact with the flat first support surface (162) and the flat second support surface (164)), when fully mated.
An electrical terminal assembly (100) according to any preceding claim, wherein the flat main contact surface (132) extents at least half the length of the first prong (130).
An electrical terminal assembly (100) according to any preceding claim, wherein the width of the first prong ( 130) is constant along the extension of the flat main contact surface (132).
An electrical terminal assembly (100) according to any preceding claim, wherein the width of the second prong (160) decreases starting from the second flat support surface (164) along the mating axis, towards the base (122).
An electrical terminal assembly (100) according to any preceding claim, wherein the flat main contact surface (132) is parallel to the flat first support surface (162) and is parallel to the flat second support surface (164), when fully mated to the blade shaped mating electrical contact (200).
An electrical terminal assembly (100) according to any preceding claim, wherein the flat main contact surface (132) is not parallel to the flat first support surface (162) or/and not parallel to the flat second support surface (164), when not mated to the blade shaped mating electrical contact (200).
An electrical terminal assembly (100) according to the preceding claim, wherein the flat first support surface (162) or/and the flat second support surface (164) are sloped towards the first prong (130), when not mated to the blade shaped mating electrical contact (200).
An electrical terminal assembly (100) according to any preceding claim, wherein the blade shaped mating electrical contact (200) comprises a rectangular cross-section.
An electrical terminal assembly (100) according to any preceding claim, wherein the blade shaped mating electrical contact (200) and the fork shaped electrical contact (120) are made of sheet metal.
An electrical terminal assembly (100) according to any preceding claim, wherein the total area of the main contact surface (132) is at least double the size than the total area of the flat first support surface (162) and the second flat support surface (164) in total.
An electrical terminal assembly (100) according to any preceding claim, wherein the first prong (130) is more rigid than the second prong (160).
An electrical junction box comprising an electrical terminal assembly (100) according to any preceding claim, wherein the fork shaped electrical contact (120) is defined of a part of an electrical bus bar and wherein the blade shaped mating electrical contact (200) is defined by a contact of a high current fuse.