Abstract:
The invention relates to an electric connector with a shield contact. This connector comprises a sleeve with a cavity designed to receive the end of at least one cable provided with a first contact and a shielding ferule, and an outer surface. This connector also comprises a metal shield contact ring having at least one inner elastic tongue extending toward the inside of the cavity to establish an electric contact with the ferule, and at least one outer elastic tongue extending toward the outside of the outer surface to establish an electric contact with the shield of a counter-connector or a housing incorporating a counter-connector having a second contact connected to the first contact, when the connector and the counter-connector are coupled.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a national stage application under 35 U.S.C. §371 of PCT Application Number PCT/EP2014/073948 having an international filing date of Nov. 6, 2014, which designated the United States, said PCT application claiming the benefit of priority under Article 8 of the Patent Cooperation Treaty to French Patent Application No. 136108, having a filing date of Nov. 12, 2013, the entire disclosure of each of which are hereby incorporated herein by reference. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The invention relates to the field of electric connectors, for example electric power connectors, and notably electric power connectors for electric or hybrid motor vehicles. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electric power connectors are used in electric or hybrid motor vehicles, for example for interconnecting a set of batteries with an electric motor, with a power converter, or the like. 
         [0004]    In hybrid and electric vehicles, the electric currents transmitted by the cables and connectors of the electric power circuits are relatively high, and may be as much as 600 amperes, or even 1500 amperes at current peaks. Consequently, the electric power carried through the electric cables and connectors can generate electromagnetic interference. It is therefore important to limit this electromagnetic interference as much as possible. For this purpose, shielding is used on the cables, as well as on the connectors. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    One object of the invention is to provide shielding which is simple and economical to manufacture and to assemble in a connector. 
         [0006]    This object is at least partially achieved by means of a shield contact ring designed for a connector assembly comprising a connector, a counter-connector and a shield wall. The connector is designed to be fitted on the shield wall. The shield wall is, for example, an electrically conductive wall of a casing in which the counter-connector is fitted. The connector comprises a sleeve made of electrically insulating material. At least a first contact is housed in this sleeve. It is attached to the end of a cable, by clamping or soldering for example. This cable is also equipped with a shielding sheath, formed by a flexible conductive braid for example. The counter-connector comprises at least one second contact designed to be connected to the first contact. The shield contact ring then comprises an inner portion, located inside the sleeve and electrically linked to the shielding sheath of the cable, and an outer portion located on the outside of the sleeve, made in one piece with the inner portion, and electrically linked to the shield wall. 
         [0007]    Thus the shield contact ring is formed by a single element which provides electrical continuity, and therefore continuity of shielding, between the shielding sheath of the cable and the casing. By limiting the number of elements providing this continuity of shielding to one only, the efficiency of the shielding is increased and the manufacture and assembly of the device providing this function is simplified, thereby making the device more economical. 
         [0008]    At least one of the inner and outer portions of the shield contact ring may comprise at least one resilient tongue in order to optimize the electric conduction on the shielding sheath of the cable and/or on the shield wall. 
         [0009]    Additionally, in some environments, and notably outside the passenger compartments of vehicles, water tightness is required. 
         [0010]    The connector may then comprise a support made of electrically insulating material, extending radially around and outside the sleeve, for example substantially perpendicularly to the longitudinal axis of the sleeve. This support is attached to the shield wall and can thus be used to fasten the connector to the casing in which the counter-connector is fitted. An interface gasket is placed between the support and the shield wall, around the sleeve and the outer portion of the shield contact ring. A cable gasket is also placed around the cable, inside the sleeve and on the other side of the first contact from the inner portion of the shield contact ring. Thus a seal is provided between the connector and the casing, while keeping the shield contact ring in a sealed area. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0011]    The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
           [0012]      FIG. 1  shows schematically, in perspective, an exemplary embodiment of a connector assembly according to the invention; 
           [0013]      FIG. 2  shows schematically, in perspective and in longitudinal section, the connector assembly of  FIG. 1 , without its protective cover; 
           [0014]      FIG. 3  shows schematically, in perspective and in longitudinal section, a connector assembly according to the invention and a cable to be inserted into this set; and 
           [0015]      FIG. 4  shows schematically, in perspective and in longitudinal section, the connector assembly of  FIGS. 1 and 2 , with its protective cover. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    An example of a connector assembly is shown in  FIG. 1 . This example relates to a connector  100  fitted on the shield wall  200 . This shield wall  200  is a wall of a power device such as a power converter or an electric motor. A counter-connector  300 , in this case taking the form of a busbar which is partially illustrated, is fitted in the power device. It has one or more contacts  310 , which in the case described here are male contacts. 
         [0017]    As shown in greater detail in  FIG. 2 , the connector  100  comprises a support  110  in the form of a plate extending substantially perpendicularly to the longitudinal axis of a plurality of sleeves  120  (numbering three in this case) and radially around and outside these sleeves. The support  110  and the sleeves  120  form a single piece, molded in electrically insulating plastic material. The support  110  has through holes  112  (four in this case, for example) for the passage of screws  114  for fastening the connector  100  to the shield wall  200  (see  FIG. 3 ). These holes  112  are reinforced by cylindrical metal bushes. 
         [0018]    Each sleeve  120  has an inner surface  124  and an outer surface  125  (see  FIG. 2 ). It also has a portion intended for insertion into the power device on which the connector  100  is fitted, through the shield wall  200 , and a portion intended to remain outside this device. Each sleeve  120  receives an electric contact  122 . In the chosen example shown in  FIG. 3 , this electric contact  122  is a female contact. It is clamped onto the stripped end of the core  402  of a cable  400 , which also has an inner sheath  404  insulating the core  402  from a shielding sheath  406 , and an outer insulating sheath  408  which surrounds the shielding sheath  406 . The cable  400  is, for example, a shielded cable with a 16 mm 2  cross section. The shielding sheath  406  is itself stripped, in one portion, so that it can slide between an outer ferrule  410  and an inner ferrule  411  and can be clamped there, so that the shielding sheath  406  is pressed between two rigid elements, thereby providing optimal electrical conduction and continuity of shielding. Upstream of the area of clamping on the stripped core  402 , the shielding sheath  406  is itself stripped in a portion which receives an electrically conductive outer ferrule  410 . Further upstream from the outer ferrule  410 , the cable  400  receives a one-piece elastomeric cable gasket  412  comprising, on the one hand, an inner surface  414  forming a seal with the outer insulating sheath  408  of the cable  400  and, on the other hand, an outer surface  416  having lips designed to bear on and make contact with a section of the sleeve  120 , thus providing a seal with the inner surface of the sleeve  120  (see  FIG. 2 ). Further upstream from the one-piece cable gasket  412 , a retaining ring  500 , fitted on the cable  400 , is inserted and clipped into the opening of a sleeve  120  designed for the insertion of the cable  400 , in order to retain the one-piece cable gasket  412  in this sleeve  120 . 
         [0019]    Each sleeve  120  also receives a shield contact ring  600  made of electrically conductive material (see  FIG. 4 ). Each shield contact ring  600  is formed by a section of metal strip wound around a longitudinal axis parallel to that of the sleeve  120  in which it is fitted. It is a single component having an inner portion  602  and an outer portion  604  made in one piece with the inner portion  602 . The cutting of a section of strip from a sheet of metal and the shaping of this section by winding are therefore particularly simple and inexpensive, notably by comparison with pressing or deep drawing methods. 
         [0020]    The inner portion  602  of the shield contact ring  600  is located inside the sleeve  120 , in the part of the sleeve designed to remain outside the device on which the connector  100  is fitted. The inner portion  602  of the shield contact ring  600  bears on a section of the inner surface  124  of the sleeve  120 , separate from the section of the inner surface  124  of the sleeve  120  in contact with the one-piece cable gasket  412 . The inner portion  602  of the shield contact ring  600  is electrically connected to the shielding sheath  406 , by means of inner resilient tongues  606  extending toward the inside of the wound section of metal strip and bearing on the outer ferrule  410  to provide an electric contact with the latter. The outer portion  604  of the shield contact ring  600  is located outside the sleeve  120  and is electrically connected, by means of outer resilient tongues  608 , to the shield wall  200 . The inner resilient tongues  606  are oriented so as to facilitate the insertion of the electric contact  122  and the outer ferrule  410  through the shield contact ring  600 . For example, they extend between a fixed end located at the opening in the sleeve  120  designed for the insertion of the cable  400  and a free end located in the part of the sleeve  120  oriented toward the counter-connector  300 . The outer resilient tongues  608  are oriented so as to facilitate the insertion of the connector  100  equipped with these tongues through an opening in the shield wall  200 . For example, they extend between a fixed end located on the part of the sleeve  120  oriented toward the counter-connector  300  and a free end located at the opening of the sleeve  120  designed for the insertion of the cable  400 . 
         [0021]    The outer portion  604  of the shield contact ring  600  extends from one edge of the wound metal strip section, and passes through one or more openings  126  formed in the wall  128  of the sleeve  120 . 
         [0022]    An interface gasket  116  is placed in a channel of the support  110 , and projects outside the latter, between the support  110  and the shield wall  200 , around one or more sleeves and the outer portion  604  of the shield contact ring  600 . This interface gasket  116  therefore provides a seal between the connector  100  and the shield wall  200 . This interface gasket  116  may, for example, provide a seal at an excess pressure of one bar, in salt spray tests for 1600 hours. Additionally, since the one-piece cable gasket  412  is placed around the cable  400 , inside the sleeve  120  and on the other side of the electric contact  122  from the inner portion  602  of the shield contact ring  600 , the shield contact ring  600  is located in a sealed area located between the one-piece cable gasket  412  and the interface gasket  116 . 
         [0023]    A cover  700  is also clipped onto the support  110  in order to guide the cables  400  at the exit from the connector  100  and prevent direct exposure of the one-piece cable gaskets  412  to liquid projection. 
         [0024]    The connector assembly described above has numerous advantages, including:
       direct connection to a busbar through the shield wall  200  without the need for access to the inside of the casing containing this busbar, thus facilitating maintenance;   electrical connection provided without clamping the cables  400  with screws; and   a connector  100  which can be fitted at the ends of cables  400  so as to be supplied to a customer ready for fitting.       
 
         [0028]    In the example described above, the shield wall  200  is a wall of a device incorporating the counter-connector  300 , but in a variant the shield wall  200  could be a wall of the counter-connector  300  itself, or, even more directly, a shield of this counter-connector  300  in the form of sheet metal or braid. In this case, it is possible to omit a shield wall  200  between the connector  100  and the counter-connector  300 . 
         [0029]    In yet another variant of the invention, the connector  100  can be used as a cable feed-through, the cable passing through the shield wall  200  with which the shield contact ring  600  forms an electric contact, but the connector  100 , when used as a cable feed-through, does not necessarily comprise an electric contact  122 , and the end of the cable  400  can be directly clamped or soldered onto a busbar or other device.