Patent Publication Number: US-9431771-B1

Title: Electromagnetically shielded connector system

Description:
TECHNICAL FIELD OF THE INVENTION 
     The invention relates to an electrical connection system, particularly an electromagnetically shielded connector system. 
     BACKGROUND OF THE INVENTION 
     Electromagnetic compatibility (EMC) requires that electronic systems and equipment be able to tolerate a specified degree of interference and not generate more than a specified amount of electromagnetic interference (EMI). EMC is becoming more important because there are so many more opportunities today for EMC issues due to increased use of electronic devices e.g. in automotive, personal computing, entertainment, and communication applications. There is increased potential for EMI susceptibility in electronic devices due to lower supply voltages, higher clock frequencies that require faster slew rates, increased electronic packaging density. There is also an increased risk of generating EMI due to proximity of high voltage electrical systems, such as electric vehicle propulsion systems. 
     One approach to EMC is providing shielding against EMI. Options for electromagnetic shielding include forming a conductive enclosure around the electronic device, such as a metallic case or plastic case formed of a conductive plastic or coated with a conductive substance. The effectiveness of the electromagnetic shielding is typically limited by apertures and seams in the shield that may be required, examples of which are removable covers for access to the electronic device, ventilation holes, and openings required for control/display devices and electrical interconnection. Methods that may be employed to mitigate the shielding loss from apertures and seams include minimizing the size and number of apertures and seams, using conductive gaskets and/or flexible contacts to seal the interface between seams, maximizing the contact area at seams, and avoiding galvanic corrosion at seams. 
     High voltage cables in electrical vehicle propulsion system use shielded wire cables to mitigate emitted EMI. The continuity of the shielding must be preserved across interconnections of the cable, therefore the connectors for these shielded cables include shields surrounding the terminals of the connectors. In order for the connectors to be separable, the shields surrounding the terminals have at least two section which have a seam between them. The shields are typically interconnected by flexible contacts. The effectiveness of the shielding provided by the shields may depend on the normal spring force exerted by the flexible contacts of a first shield on a second mating shield, especially in a high vibration environment e.g., in an automobile. Such shields used in connectors are typically formed of sheet metal and the normal spring force exerted by the flexible contacts of a first shield be diminished by deformation of the sheet metal of the second shield caused by the flexible contacts, thus diminishing the electromagnetic shielding effectiveness of the connector system. Therefore, a connector system with improved electromagnetic shielding capability is desired. 
     The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with an embodiment of the invention, an electromagnetically shielded electromagnetically shielded connector system is provided. The electromagnetically shielded connector system, includes a first connector and a second connector. The first connector further includes a first electrical terminal and a first electromagnetic shield longitudinally surrounding the first electrical terminal. The first electromagnetic shield defines a flexible interface contact longitudinally projecting from an end of the first electromagnetic shield. The second connector further includes a second electrical terminal configured to mate with the first electrical terminal and a second electromagnetic shield longitudinally surrounding the second electrical terminal. The second electromagnetic shield is configured to be electrically connected with the first electromagnetic shield at least via the flexible interface contact. The second electromagnetic shield is surrounded by a supporting member. At least a portion of an outer surface of the second electromagnetic shield is in intimate contact with the supporting member. The second electromagnetic shield is configured to be disposed intermediate the flexible interface contact and the supporting member. The flexible interface contact is formed and configured to exert a normal spring force on the second electromagnetic shield. 
     An entire outer surface of the second electromagnetic shield may be in intimate contact with the supporting member. 
     According to one particular embodiment, he second electromagnetic shield defines a rigid interface contact longitudinally projecting from an end of the second electromagnetic shield configured to interface with the flexible interface contact. The supporting member defines an extension projecting from an end of the supporting member and wherein the outer surface of the rigid interface contact is in intimate contact with the extension. The first connector defines a groove configured to receive the rigid interface contact and the extension. 
     The supporting member may also be configured to retain a complaint seal longitudinally surrounding the second connector. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective exploded view of an electromagnetically shielded connector assembly according to one embodiment; 
         FIG. 2  is a cross sectional view of the electromagnetically shielded connector assembly of  FIG. 1  in an unmated condition according to one embodiment; 
         FIG. 2A  is a close up cross sectional view of the electromagnetically shielded connector assembly of  FIG. 1  in an unmated condition according to one embodiment; 
         FIG. 3  is a close up perspective cross sectional view of flexible interface contacts of the electromagnetically shielded connector assembly of  FIG. 1  in an unmated condition according to one embodiment; 
         FIG. 4  is a cross sectional view of the electromagnetically shielded connector assembly of  FIG. 1  in an unmated condition according to one embodiment; 
         FIG. 4A  is a close up cross sectional view of the electromagnetically shielded connector assembly of  FIG. 1  in an unmated condition according to one embodiment; and 
         FIG. 5  is a perspective bottom view of the electromagnetically shielded connector assembly of  FIG. 1  according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Presented herein is an electromagnetically shielded connector system that is designed to interconnect shielded wire cables, such as those used in the high voltage circuits of electrical vehicle propulsion system. The connector system include a pair of connectors, each having mating electrical terminals. An electromagnetic shield surrounds the terminals of each of the connectors. A first electromagnetic shield has at least one interface contact that projects from the end of the shield and contacts the second electromagnetic shield when the connectors are fully mated. The interface contact is configured to exert a normal spring force on the second electromagnetic shield. The second electromagnetic shield is surrounded by a rigid supporting member that is designed to inhibit outward flexing of the second electromagnetic shield thus maintaining the normal spring force between the interface contacts and the second electromagnetic shield. 
       FIG. 1  illustrates a non-limiting example of an electromagnetically shielded connector system  10 , hereinafter referred to as the connector system  10 . The connector system  10  includes a first connector  100  and a second connector  200 . 
     The first connector  100  in the connector system  10  is a header connector  100 . As illustrated in  FIG. 2 , the header connector  100  is based around a header connector body  102  formed of a dielectric polymeric material, such as polybutylene terephthalate (PBT), polypropylene (PP), or polyamide (PA, commonly known as NYLON). The header connector  100  includes a pair of conductive male pin terminals  104 , hereinafter referred to as the male terminals  104 , mounted within the header connector body  102 . A first electromagnetic shield  106 , hereinafter referred to as the first shield  106 , is attached to the header body and longitudinally surrounds the male terminals  104  about a longitudinal axis X. The first shield  106  is formed of a sheet of conductive material, such as a tin plated copper alloy. Methods for forming such shields from sheet metal are well known to those skilled in the art. The first shield  106  has the form of a rectangular tube with openings defined by each end and rounded corners, although other shapes for the first shield  106  may be envisioned. As shown in  FIGS. 2A and 3 , the first shield  106  defines at least one flexible interface contact  112  that longitudinally projecting from one end of the first shield  106 . 
     The header connector  100  is configured to be attached to the conductive bulkhead, in this example by conductive treaded fasteners (not shown). The first shield  106  may define flexible tabs  114  that are configured to establish an electrical connection between the bulkhead and the first shield  106 . Alternatively, the first shield  106  may be electrically connected by a tab to a conductive boss surrounding an aperture though which the conductive fastener passes, thereby forming an electrical connection between the first shield  106  and the bulkhead. 
     The second connector  200  in the electromagnetically shielded connector system  10  is the cable connector  200 . As illustrated in  FIG. 2 , the cable connector  200  is based around a cable connector body  202  formed of a dielectric polymeric material, such as PBT, PP, or NYLON. The cable connector  200  includes a pair of conductive female socket terminals  206  connected to shielded wire cables  208 , hereinafter referred to as the female terminals  206 , mounted within the cable connector body  202 . A second electromagnetic shield  210 , hereinafter referred to as the second shield  210 , longitudinally surrounds an aperture  212  along the longitudinal axis X surrounding a portion of the header connector body  102 . The second shield  210  is formed of a sheet of conductive material, such as a tin plated copper alloy. The second shield  210  has the form of a rectangular tube with openings defined by each end and rounded corners and has a complementary shape to the first shield  106  and is configured to receive the first shield  106  within an inner wall  216  of the second shield  210 . As shown in  FIGS. 4 and 4A , when the first shield  106  is received within the second shield  210 , the interface contacts  112  contact a contact area  218  on the inner wall  216  of the second shield  210 , thereby making an electrical contact between the first and second shields  106 ,  210 . The interface contacts  112  are formed to exert a normal spring force F on the contact area  218 . Without subscribing to any particular theory of operation, a high normal spring force improves the EMC/EMI performance of the connection between the first and second shields  106 ,  210  in a higher vibration environment, such as that found in an automobile. 
     As best shown in  FIG. 5 , an outer wall  220  of the second shield  210  is longitudinally surrounded by a rigid supporting member  222  along the longitudinal axis X. The supporting member  222  is also formed of a dielectric polymeric material, such as PBT, PP, or NYLON. The supporting member  222  is attached to the cable connector body  202 . The second shield  210  is configured to be disposed intermediate the interface contact  112  and the supporting member  222 . At least a portion of the outer wall  220  of the second shield  210  is in intimate contact with the supporting member  222  in the vicinity of the contact area  218 . According to the illustrated example, the entire outer wall  220  of the second shield  210  is in intimate contact with the supporting member  222 . Without subscribing to any particular theory of operation, the supporting member  222  inhibits flexing of the second shield  210  caused by the interface contacts  112 , thus preventing a reduction in the normal spring force F between the interface contacts  112  and the second shield  210  and thereby improving the EMC/EMI performance as explained above. 
     According to the illustrated example and as shown in  FIG. 4 , the second shield  210  defines a pair of rigid interface tabs  224  longitudinally projecting from an end of the second shield  210  forming an intimal contact area  228  configured to interface with the interface contact  112 . This interface tabs  224  is configured to make contact with the interface contacts  112  prior to contact between the male and female terminals  104 ,  206 , thereby establishing a ground path between the shield  244  of the shielded wire cable  208  and the conductive bulkhead prior to establishing connection between the male and female terminals  206 . The supporting member  222  defines an extension  234  projecting from an end of the supporting member  222 . The outer surface  238  of the rigid interface tabs  224  are in intimate contact with the extension  234 . 
     As shown in  FIGS. 2 and 5 , the header connector body  102  defines a groove  116  that is configured to receive the rigid interface tabs  224  and the extension  234  when the cable connector  200  is fully mated with the header connector  100 . 
     The supporting member  222  is also configured to retain a complaint body seal  240  longitudinally surrounding the cable connector body  202  along the longitudinal axis X that is configured to provide an environmental seal between the cable connector body  202  and the header body. The connector system  10  also includes a header seal  118  configured to provide an environmental seal between the header connector body  102  and the bulkhead. The connector system  10  further includes compliant cable seals  242  between the shielded wire cables  208  and the cable connector body  202 . These seals  118 ,  240 ,  242  are intended to seal out environmental contaminants for the interior of the header connector body  102  and the cable connector body  202  that may act as electrolytes and cause galvanic corrosion between the male and female terminals  104 ,  206  and/or the first and second shield  106 ,  210  that would degrade the current carrying performance and EMC/EMI performance of the connector system  10 . The seals  118 ,  240 ,  242  may be formed of a silicone-based material. 
     The cable connector  200  shown in this example also includes a third electromagnetic shield  244 , hereinafter referred to as the third shield  244 , that is attached to the cable connector body  202  and longitudinally surrounds the female terminals  206  about a lateral axis Y. The third shield  244  defines the aperture  212  in which the second shield  210  is disposed. The third shield  244  is electrically connected to the shield  244  of the shielded wire cable  208 , in this example by connective ferrules  246 , to provide an electrical connected between the shield  244  of the shielded wire cable  208  and the bulkhead. The third shield  244  is formed of a sheet of conductive material, such as a tin plated copper alloy. 
     According to the connector system  10  shown here, the cable connector  200  further includes a mating assist lever  248  having mating grooves  250  that receive mating posts  120  defined by the header connector  100 . The cable connector  200  and the header connecter are drawn from and unmated position as shown in  FIG. 2  to a mated position as shown in  FIG. 4  as the mating assist lever  248  is rotated from an open position to a closed position. 
     Accordingly an electromagnetically shielded connector system  10  is provided. The connector system  10  provides the benefit of improved EMC/EMI performance in high vibration environments, at least due to a supporting member  222  that increases the normal spring force of the connection between the interface contacts  112  of the first shield  106  and the second shield  210 . The seals  118 ,  240 ,  242  of the connector system  10  inhibit the intrusion of environmental contacts that could cause galvanic corrosion. 
     While the connector system  10  illustrated herein is characterized as a right angle (ninety degree) header connector  100  assembly with a mating assist lever  248 , features of this invention may also be applied to a straight (one hundred eighty degree) connector assembly. The features of this invention may also be applied to a connector assembly that neither includes a mating assist lever nor a header connector configured to be mounted to a conductive bulkhead but rather may include a second cable connector having male terminals. 
     While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. Moreover, the use of the terms first, second, upper, lower etc. does not denote any order of importance or location, but rather the terms first, second, upper, lower etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.