EP4636957A1

EP4636957A1 - Cable assembly and kit to manufacture such cable assembly

Info

Publication number: EP4636957A1
Application number: EP24170535.9A
Authority: EP
Inventors: Gildas DONFACK; ShobanKumar BASKARAN; Laurent Morin; Francois Lavertu
Original assignee: Aptiv Technologies AG
Current assignee: Aptiv Technologies AG
Priority date: 2024-04-16
Filing date: 2024-04-16
Publication date: 2025-10-22

Abstract

The cable assembly comprises :
- an electrical connector (6) having an inner housing (36) with a cavity (40) in which is receive a cable (4) tip,
- an outer ferrule (72) comprising a distal end (76) that extends beyond an aperture (46) of the cavity and that comes in direct mechanical and electrical contact with an outer electromagnetic shield (38),
- an outer annular seal (100) interposed between an outward face of the outer ferrule and an inward face of the inner housing to ensure water-tightness between the outer ferrule and the inner housing, and
- an inner annular seal (102) interposed between an inward face of the outer ferrule and an outer insulative sheath (12) of the cable (4) to ensure water-tightness between the outer ferrule and the cable.

Description

The invention relates to a cable assembly and to a kit to manufacture such a cable assembly.
A cable assembly comprises :

an electrical cable having a bread and an outer insulative sheath that surrounds the braid, and
an electrical connector fixed at a tip of the cable.

Such a cable assembly is used in the field of vehicle connectivity, and in particular but not exclusively, to the field of high-power connectivity.
When cable assemblies are used in high voltage/intensity applications, it is desirable to maintain, through such cable assemblies, the shielding continuity that is provided at the cable level. In addition, it is required to prevent humidity, salt spray, dust, etc. from entering into the electrical connector. However, combining both shielding continuity and water-tightness raises difficulties in terms of feasibility, manufacturing, mounting, costs, etc.
In order to achieve both shielding continuity and water-tightness, the electrical connector typically comprises:

an outer housing made of electrically insulating material,
an inner housing made of electrically insulating material,
an outer electromagnetic shield that is disposed between the outer housing and the inner housing, and
an outer ferrule to electrically connect the cable braid to the outer electromagnetic shield, the outer ferrule being accommodated within the inner housing.

The outer ferrule has one proximal end which is in direct mechanical and electrical contact with the cable braid and an opposite distal end. In the prior art known by the applicant, the distal end of the outer ferrule is electrically connected to the outer shield by the way of an electrically conductive seal. This electrically conductive seal ensures, in addition, water-tightness between the outer ferrule and the outer shield so that no dust or water can enter the inner housing to reach the electrical connection between the outer ferrule and the cable bread.
The use of an electrically conductive seal is an interesting solution because it reduces the number of pieces of the cable assembly. However, the applicant has noted that the electrical connection through the electrically conductive seal is unstable.
Accordingly, the invention aims at proposing a cable assembly with a more stable electrical connection between the outer ferrule and the outer electromagnetic shield.
The invention is exposed in the enclosed set of claims.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of a cable assembly,
Figure 2 is a perspective view of the tip of a cable of the cable assembly of figure 1,
Figure 3 is a perspective view of an electrical connector of the cable assembly of figure 1,
Figure 4 is a longitudinal and vertical cut of the connector of figure 3,
Figure 5 is a longitudinal cut of an outer ferrule of the cable assembly of figure 1,
Figure 6 is a cross sectional view of a region of the connector of figure 3,
Figure 7 is a transversal cut of the connector of figure 3 showing the outer ferrule of figure 5.

In this specification, the terminology, conventions and definitions of the terms used in this text are introduced in Chapter I. Then, detailed examples of embodiments are described in Chapter II with reference to the figures. In Chapter III, variants of these embodiments are presented. Finally, the advantages of the various embodiments are described in Chapter IV.

Chapter I : Definitions terminologies and conventions :

In the figures, the same reference is used to designate the same element in each figure.
The figures are oriented with respect to an orthogonal XYZ coordinate system, where the X and Y directions are horizontal and the Z direction is vertical. Terms such as "above", "below", "top", "bottom", "upper", "lower" are defined in relation to the Z direction. Terms "right" and "left" are defined relative to direction X.
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without all of these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.
An electrically conductive material is a material whose electrical conductivity at 20°C is greater than 10⁴ S/m or 10⁶ S/m.
An electrically insulating material is one whose electrical conductivity, at 20°C, is less than 10^-10 S/m or 10^-14 S/m.
A high DC voltage is a DC voltage greater than 100 Vdc or 500 Vdc. Generally, a high DC voltage is a voltage that is smaller than 5000 Vdc or 2000 Vdc.
A high DC current is a DC current greater than 10 A or 20 A. Generally, a high DC current is smaller than 500 A or 100 A.
The expression "an element made of material A" or the expression "an element in material A" means that material A represents 90% or 95% of the mass of this element.
In this document, the term "counter-connector" generally and broadly designates any element intended to be electrically connected to a connector. It can therefore be another connector, a housing on which connection components are assembled, a wall through which an electrical connection must be made, etc.
High power electrical connector, such as those used in electrical vehicles, may be required to conduct 90 kilowatts or more of electrical power.

Chapter II : Examples of embodiments

Figure 1 shows a cable assembly 2. Cable assembly 2 comprises an electrical cable 4 and an electrical connector 6 fixed on a tip of cable 4. Connector 6 is design to be plugged into a counter-connector 8.
Here, cable assembly 2 is a high-voltage cable assembly intended, for example, to electrically connect a battery pack of an electric vehicle to a DC/DC converter or to an on-board charger (OBC). An onboard charger (OBC) is a power electronics device in electric vehicles that converts AC power from external sources, such as residential outlets, to DC power to charge the vehicle's battery pack. Accordingly, cable 4 and connector 6 are designed to support, without any damage, a high DC current and a high DC voltage.
Figure 2 shows a tip 10 of cable 4 that extends in direction X. Cable 4 comprises, from the exterior to the interior of the cable, an outer insulative sheath 12, a braid 14, an inner insulative sheath 16 and an electrical conductor 18. The insulative sheath 12 and 16 are made in electrically insulating material. Braid 14 and conductor 18 are made in a electrically conductive material. Braid 14 forms, in use, an electromagnetic shield. Conductor 18 is for example made of copper.
Figures 3 to 7 shows in more detail connector 6 and parts of the cable assembly 2 used to connect cable 4 to connector 6.
As shown in Figure 3, connector 6 comprises two female power contact 20, 22, an outer housing 24, a gear cams 26 of a mate assist system 28, a slider 30 of the mate assist system 28 and a retainer 32.
In this embodiment, power contact 20 is electrically connected to cable 4 and power contact 22 is electrically connected to an additional cable 5 of cable assembly 2. Cable 5 is typically identical to cable 4. Power contact 20 extends along an axis 34 parallel to direction X.
Outer housing 24 is made of an electrically insulating material like a dielectric material. For example, outer housing 24 is made of molded plastics.
The mate assist system 28 is for example similar to the one disclosed in application WO2013093546A1 . The mate assist system 28 is mounted on outer housing 24. In particular, slider 30 is sliding along outer housing 24 in direction X.
Retainer 32 is, among other things, used to retain the tips of the cables 4 and 5 fixed inside connector 6. Retainer 32 is made of an electrically insulating material like a dielectric material. For example, retainer 32 is made of molded plastics.
Figure 4 shows a longitudinal cut of connector 6 in a vertical plan containing axis 34. As shown in Figure 4, connector 6 further comprises an inner housing 36 and an outer electromagnetic shield 38.
Inner housing 36 is made of an electrically insulating material like a dielectric material. For example, inner housing 24 is made of molded plastics. Inner housing 36 mainly extends, in direction X, from retainer 32 to power contact 20. Inner housing 36 is fixed inside the outer housing 24. On one side, inner housing 36 receives power contact 20 and, on the opposite side, inner housing 36 receive the tip 10 of cable 4. For each cable tip to receive, inner housing 36 comprises a corresponding cavity. Accordingly, in this example, inner housing 36 comprises two cavities. The cavity in which is accommodated tip 10 is marked 40 in figure 4. Cavity 40 extends along axis 34. Therefore, inner housing 36 comprises an inward face 42 that delimits cavity 40. For example, inward face 42 is a surface of revolution whose axis of revolution coincides with axis 34. On the side opposite to face 42, inner housing 36 comprises an outward face 44 which is turned toward outer housing 24. When connector 6 is assembled with cable 4, tip 10 is accommodated inside cavity 40.
Inner housing 36 also comprises an aperture 46 through which is inserted tip 10 to enter inside cavity 40. Aperture 46 is located within a vertical plan P₄₆ which is perpendicular to axis 34 and that is flush with the right end of inner housing 34. Aperture 46 is for example a cyrcular aperture centered on axis 34.
Outer shield 38 is disposed between outer housing 24 and inner housing 36. Outer shield 38 surrounds inner housing 36. Accordingly, outer shield 38 also surrounds all the cavities of inner housing 36. Typically, outer shield 38 is formed as a single annular band. Outer shield 36 is made of an electrically conductive material, like a metal. For example, it is a deep drawn piece, i.e. it is formed by a deep-drawing process. Such a deep drawn piece as the advantage of providing seamless inward and outward faces.
Outer shield 38 has a right free end 50 that extends beyond vertical plan P₄₆ in a direction opposite to direction X. In this embodiment, free end 50 comprises flexible strips 51 (Figure 7) integrally formed with the remaining part of outer shield 38. Figure 7 is a cross section in a vertical plan P₃₂ shown in figure 3.
As shown if Figure 4, retainer 32 forms a cap that is fixed on a right end of outer housing 24. More precisely, in this embodiment, retainer 32 is configured to prevent water splash to directly reach the aperture 46 of inner housing 36. For example, to this end, retainer 32 comprises a border 60 that surrounds and covers the left end of outer housing 24.
In addition, for each cable to connect to connector 6, retainer 32 comprises a respective duct that allows the cable to pass though retainer 32. Cable 4 is inserted in a duct 62 of retainer 32. Duct 62 continuously extends along axis 34, in direction X, from a right extremity 64 to a left extremity 66. Extremity 66 is close to plan P₄₆. Extremity 66 has in inward face turned toward cable 4 and, on the opposite side, an outward face.
To electrically connect bread 14 to outer shield 38, cable assembly 2 comprises an inner ferrule 70 and an outer ferrule 72. Inner ferrule 70 and outer ferrule 72 are made of electrically conductive material like a metal.
Inner ferrule 70 is a revolution cylinder that is inserted between sheath 16 and bread 14. For this reason, sheath 12 is removed from the place where inner ferrule 70 is located, in use, till the end of tip 10.
As shown in Figure 5, outer ferrule 72 extends from a proximal end 74 to a distal end 76. Ferrule 72 is a revolution part, revolution axis of which coincides with axis 34. Ferrule 72 has an outward face 78 facing the inward face 42 of inner housing 36 and an inward face 80 facing tip 10.
Proximal end 74 is directly mechanically and electrically connected to bread 14. More precisely, proximal end 74 comprises a revolution cylinder clamped on inner ferrule 70 so as to sandwich bread 14 between inner ferrule 70 and proximal end 74. To this end, the inner diameter of proximal end 74 is closed to the outer diameter of ferrule 70.
In this embodiment, distal end 76 is directly mechanically and electrically connected to the free end 50 of outer shield 38 as shown in figure 6. Figure 6 is a partial cut of connector 6 in an horizontal plan containing axis 34. The contact between distal end 76 and outer shield 38 take place only on the side of distal end 76 which is the closest of the free end 50. This side is located on the left of cable 4 in Figure 7. To this end, in use, distal end 76 is located outside cavity 40. Here, distal end 76 is a revolution cylinder, outer diameter of which is great enough to come in mechanical contact with free end 50 of shield 38. The outer diameter of distal end 76 is greater than the diameter of the aperture 46 of inner housing 36.
Ferrule 72 has also two successive intermediate portions 82 and 84 located between ends 74 and 76. Intermediate portion 82 is closer to proximal end 74 and further away from distal end 76. Reversely, intermediate portion 84 is closer to distal end 76 and further away from proximal end 74. Both portions 82 and 84 are revolution cylinders. The outer diameters of the revolution cylinders corresponding to end 76, portions 82, 84 and end 74 are decreasing when going in direction X. In use, portions 82, 84 are accommodated inside cavity 40.
To further increase the stability of the electrical connection between free end 50 and distal end 76, in this embodiment, the cable assembly further comprises a pusher 90 (Figure 7) that constantly urges distal end 76 against free end 50 of outer shield 38.
In this embodiment, pusher 90 comprises several ribs 92 arranged on the outward face of the extremity 66 of duct 62 to constantly urge distal end 76 against free end 50 when retainer 32 is fixed on outer housing 24. Ribs 92 are made of an insulating material. Here, ribs 92 are integrally formed with retainer 32.
Each rib 92 mainly extends in a direction parallel to direction X. They are evenly distributed around the periphery of duct 62. Here, pusher 90 comprises four ribs 92. As shown in Figure 7, in use, only two of them comes into mechanical contact with the inward face of distal end 76 to urge it against strips 51 of free end 50. In Figure 7, the two ribs 92 that come in mechanical contact with free end 50 are circled by dotted lines.
More precisely, the high of each rib 92 progressively ramps from an initial high to a final high when going from extremity 66 toward extremity 64. A high of rib 92 is measured along a radial axis that cuts axis 34 and belongs to an plan perpendicular to axis 34. The initial high is small enough to allow the introduction of rib 92 inside distal end 76 without initially touching the inward face of ferrule 72. The final high is great enough to engage the inward face of distal end 76 when retainer 32 is fixed on outer housing 24 and to push it away. Thus, when retainer 32 is displaced along the axis 34 in the direction X to assemble it on outer housing 24, two ribs 92 come in mechanical contact with the inward face of distal end 76 to push it against strips 51 of free end 50. In the final position of retainer 32, shown in figure 4, two ribs 92 constantly urge distal end 76 against free end 50 to establish an electrical connection stable even in presence of vibrations.
To ensure the water-tightness of cavity 40, the cable assembly also comprises an outer annular seal 100 and an inner annular seal 102. Both seals 100 and 102 are made of electrically insulating material.
Seal 100 ensures water-tightness between outer ferrule 72 and inner housing 36. To this end, seal 100 is in direct mechanical contact on one side with the outward face 78 of outer ferrule 72 and, on a opposite side, with the inward face 42 of inner housing 36. Here, seal 100 is directly interposed between intermediate portion 82 and inward face 42 of inner housing 36. Seal 100 prevents introduction of water or dust in cavity 40 by a path shown in dotted line in figure 4 and marked by arrows 104. Such a path is passing between border 60 and the outer housing 24 and then between inner housing 36 and outer ferrule 72.
Seal 102 ensures water-tightness between outer ferrule 72 and cable 4. To this end, seal 102 is in direct mechanical contact on one side with the inward face 80 of outer ferrule 72 and, on a opposite side, with insulative sheath 12 of cable 4. Here, seal 102 is directly interposed between intermediate portion 84 and cable 4. Seal 102 prevents introduction of water or dust in cavity 40 by a path shown in dotted line in figure 4 and marked by arrow 106. This path is passing between duct 62 and cable 4.
In this embodiment, cable assembly 2 also comprise a cable seal 108. Seal 108 is interposed between the inward face 42 of inner housing 36 and insulative sheath 16 of tip 10. Compare to seals 100 and 102, seal 108 is located further away into cavity 40 in direction X. Seal 108 ensures water-tightness between inner housing 36 and insulative sheath 16. This is useful in case insulative sheath 12 is damage so that humidity can propagate between the insulative sheaths 12 and 16 to reach cavity 40. In such a case, seal 108 prevents water from reaching the electrical connection between conductor 18 and power contact 20.

Chapter III : Variants of the previous embodiments :

Connector 6 may comprise more than two female power contacts. In a simplified embodiment, connector 6 comprises only one female power contact.
A female power contact may be replaced by a male power contact.
The mate assist system 28 may be omitted.
Connector 6 may also comprise additional component like a CPA device, where "CPA" stands for "Connector Position Assurance".
Other embodiment are possible for retainer 32. For example, in a simplified embodiment, retainer 32 is not designed to prevent water splash from directly reaching aperture 46 of inner housing 36 but only to maintain pusher 90 in the right position when retainer 32 is fixed on outer housing 24.
In a simplified embodiment, free end 50 does not comprise strips 51.
Other embodiments of pusher 90 are possible. For example, pusher 90 does not need to be integrally form with retainer 32. Pusher 90 may be manufactured in a material different from the material of retainer 32. In a simplified embodiment, pusher 90 comprises only one rib 92. Pusher 90 may also comprise more than four ribs 92. In another embodiment, pusher 90 is mechanically independent from retainer 32. For example, pusher 90 comprises a ring that surrounds cable 4 and the ribs 92 are arranged on the periphery of this ring. In use, the ring is interposed between seal 102 and retainer 32.
In a very simplified embodiment, pusher 90 is omitted.
Even if it not necessary, seals 100 and 102 can be made of electrically conductive material.
Several of the above disclosed variants may be combined together in a the same embodiment of the busbar and of the connector.

Chapter IV : Advantages of the disclosed embodiments :

The disclosed cable assembly has a more stable electrical connection between outer ferrule 72 and outer shield 38 because the free end 50 of the outer ferrule 72 comes in direct mechanical and electrical contact with outer shield 38. This improvement in the electrical connection between outer ferrule 72 and outer shield 38 is achieved while preserving a water-tightness as good as in the previously known cable assembly and without complexifying the structure of the assembly 2. For example, the disclosed assembly uses the same number of seals as in the previously known cable assembly.
The use of pusher 90 improves the stability of the electrical connection between outer ferrule 72 and outer shield 38 in presence of vibrations.
Having pusher 90 integrally formed with retainer 32 simplifies assembly 2 and makes it easier to manufacture.
Using ribs 92 arranged on the outward face of duct 62 of retainer 32 to urge distal end 76 of outer ferrule 72 against outer shield 38 is a simple and robust way to manufacture the pusher.
Using outer ferrule 72 with intermediate portions 82 and 84 that form annular sits to receive seals 100 and 102 improves the water-tightness.
Using seals 100 and 102 made of electrically insulating material simplifies the manufacturing of assembly 2.
If insulative sheath 12 of cable 4 is damage, water may reach cavity 40. Cable seal 108 avoids that, in case of such a damage, the water reaches the bare end of the electrical cable, i.e conductor 18. Thus, even is such a damage exists, the electrical connection between connector 18 and power contact 20 is not affected.

Claims

A cable assembly comprising :
- an electrical cable (4) having a bread (14) and an outer insulative sheath (12) that surrounds the braid,

- an electrical connector (6) fixed at a tip of the cable, wherein the electrical connector comprises:
- an outer housing (24) made of electrically insulating material,

- an inner housing (36) made of electrically insulating material accommodated inside the outer housing, the inner housing having :
- an outward face (44) turned toward the outer housing and, on the opposite side, an inward face (42),

- a cavity (40) delimited by the inward face, the cable tip being received inside the cavity,

- an aperture (46) through which is inserted the cable tip to enter the cavity,

- an outer electromagnetic shield (38) that is disposed between the outer housing and the inner housing, the electromagnetic shield surrounding the inner housing,

- an outer ferrule (72) to electrically connect the cable braid to the outer electromagnetic shield, the outer ferrule being at least partially housed within the cavity of the inner housing and comprising :
- an inward face (80) that surrounds the cable tip received in the cavity of the inner housing, and

- an outward face (78) turned toward the inner housing,

characterized in that :
- the outer ferrule (72) comprises a distal end (76) that extends beyond the aperture (46) of the cavity and that comes in direct mechanical and electrical contact with the outer electromagnetic shield (38), and

- the cable assembly comprises :
- an outer annular seal (100) interposed between the outward face of the outer ferrule and the inward face of the inner housing to ensure water-tightness between the outer ferrule and the inner housing, and

- an inner annular seal (102) interposed between the inward face of the outer ferrule and the outer insulative sheath of the cable to ensure water-tightness between the outer ferrule and the cable.
The cable assembly of Claim 1, wherein the cable assembly further comprises a pusher (90) that constantly urges the distal end of the outer ferrule against the outer electromagnetic shield.
The cable assembly of Claim 2, wherein :
- the cable assembly further comprises a retainer (32) configured to close the aperture of the inner housing and to be fixed on the outer housing, the retainer comprising a duct (62) which received the cable, and

- the pusher is integrally formed with the retainer.
The cable assembly of Claim 3, wherein :
- the duct (62) comprises an inward face turned toward the cable, and an outward face on the opposite side, and

- the pusher comprises at least a rib (92) arranged on the outward face of the duct to constantly urge the distal end of the outer ferrule against the outer electromagnetic shield when the retainer is fixed on the outer housing.
The cable assembly according to anyone of the preceding claims, wherein :
- the outer ferrule comprises a proximal end (74) in direct mechanical and electrical contact with the bread and a first and a second intermediate portions (82, 84) both situated between the proximal end and the distal end, each intermediate portion comprising a revolution cylinder and the diameter of the revolution cylinder of the first and second intermediate portions being differents, and

- the outer annular seal (100) is interposed between the revolution cylinder of the first intermediate portion and the inner housing and the inner annular seal (102) is interposed between the revolution cylinder of the second intermediate portion and the outer insulative sheath.
The cable assembly according to anyone of the preceding claims, wherein both outer and inner annular seals (100, 102) are made of electrically insulating material.
The cable assembly according to anyone of the preceding claims, wherein :
- the cable comprises, from the exterior to the interior of the cable, the outer insulative sheath (12), the braid (14), an inner insulative sheath (16) and an electrical conductor (18), and

- the cable assembly comprises an annular cable seal (108) directly interposed between the inner insulative sheath and the inward face of the inner housing to ensure water-tightness between the inner insulative sheath and the inner housing.
A kit to manufacture a cable assembly according to anyone of the preceding claims, the kit comprising :
- an electrical connector (6) intended to be fixed at a tip of an electrical cable having a bread and an outer insulative sheath that surrounds the braid, wherein the electrical connector comprises:
- an outer housing (24) made of electrically insulating material,

- an inner housing (36) made of electrically insulating material accommodated inside the outer housing, the inner housing having :
- an outward face turned toward the outer housing and, on the opposite side, an inward face

- a cavity (40) delimited by the inward face, the cable tip being intended to be received inside this cavity,

- an aperture (42) through which the cable tip has to be inserted to enter the cavity,

- an outer electromagnetic shield (38) that is disposed between the outer housing and the inner housing, the electromagnetic shield surrounding the inner housing,

- an outer ferrule (72to electrically connect the cable braid to the outer electromagnetic shield, the outer ferrule being configured to be at least partially housed within the cavity of the inner housing and comprising :
- an inward face that surrounds, in use, the cable tip received in the cavity of the inner housing, and

- an outward face turned, in use, toward the inner housing,

characterized in that :
- the outer ferrule (72) comprises a distal end (76) that extends beyond the aperture (46) of the cavity and that comes in direct mechanical and electrical contact with the outer electromagnetic shield (38), and

- the kit comprises :
- an outer annular seal (100) to be interposed between the outward face of the outer ferrule and the inward face of the inner housing to ensure water-tightness between the outer ferrule and the inner housing, and

- an inner annular seal (102) to be interposed between the inward face of the outer ferrule and the outer insulative sheath of the cable to ensure water-tightness between the outer ferrule and the cable.