Sealing system for electrical connectors

Abstract: A sealing system (44) is provided between an electrical connector assembly (10) and another connector component (12), panel (14)or the like. The connector assembly includes a housing (32) having a mating end (18) with a seal-receiving channel (48) and a resilient seal (50) received in the channel. The seal includes a sealing groove (52) having a given width and a given depth. The connector component includes a sealing lip (54) insertable into the sealing groove when the connector assembly and the connector component are mated along a mating axis (A). The sealing lip has a width greater than the width of the sealing groove and a length relative to the depth of the sealing groove such that the lip is spaced from the bottom of the groove when the connector assembly and the connector component are in mated condition. Therefore, only sealing forces normal to the mating axis are effected between the sealing lip and the sealing groove. A radio frequency seal (46) is provided by point contacts (60) between an edge of a flange (50) of the connector assembly engaging an abutment surface (62) of the connector component, the flange being overlapped with the sealing lip and another flange (64) of the connector component, whereby a labyrinth path is defined through an interface area including the point contacts (60).

Description: Field of the Invention This invention relates to a connector assembly according to the preamble of claim 1 and, particularly, to a system for sealing such an electrical connector assembly, such as in adverse environments. Background of the Invention Sealed electrical connector assemblies are used in a wide variety of applications wherein the assemblies are subjected to a wide range of environmental conditions and physical abuse. For example, one suchaupplication is where electrical connectors are mounted in the engine compartment of an automobile or other vehicle, although the invention is not limited to such an application. In automotive applications, electrical connectors are incorporated into circuits that monitor and/or control a variety of vital vehicular functions. For example, steering, suspension and engine operating conditions continuously are monitored in many vehicles. Signals corresponding to sensed operating conditions may be transmitted to displays in the passenger compartment to enable the driver to take appropriate action in response to the displayed information. Other sensed conditions are monitored by controls which automatically alter some aspect of the vehicular performance to compensate for the sensed conditions. The electronic circuitry also extends into other nonessential aspects of the vehicle performance, including climate control, sound systems and the like. Electrical connectors incorporated into the circuitry of an automotive vehicle are subjected to extreme environmental conditions, including broad ranges of temperature, exposure to moisture, subjection to almost continuous vibration during use and frequent subjection to direct physical shock. The connectors are exposed to soil and are frequently splashed with water, lubricants and fuels. In addition to practically continuous subjection to vibrations during use, the connectors frequently are subjected to sharp jarring movement as the vehicle traverses a rough road, and the connectors often are directly contacted by maintenance personnel working in the engine compartment. Even aside from exposure to adverse conditions, such as in automotive applications as described above, mating electrical components have a tendency to "creep", bow and distort under pressure over a period of time, particularly at elevated temperatures. When a pair of electrical components are sealed in mated condition, this causes the seals to lose their effectiveness. The electrical connector assembly referred-to above (EP-A 0 509 454) has its annular seal positioned in a channel located in the first connector, surrounding the connecting interface, with the seal engaged by walls of the other connector component or panel. The seal is placed in a compressive state by forces applied mainly normal to the mating axis. While the seal is initially effective, problems arise over time due to the adverse environmental conditions of the connector as well as when creeping sets in, whereby the sealing forces acting on the seal decrease. This invention is directed to an improved environmental seal to solve these problems. Another problem with electrical connectors of the character described, including automotive applications, is that the electrical circuitry often must be protected from disruptions or "noise" caused by electromagnetic interference, radio frequency interference, electrostatic discharges and/or electromagnetic pulses. In automotive applications, electronic circuitry, including computer circuitry, have become common to control, monitor or otherwise interconnect all kinds of electrical circuitry within the operative system of the vehicle, as described generally above. Therefore, not only do such electrical connectors have to be sealed against moisture and other contaminants, but the connector assemblies must be provided with filtering and shielding capabilities, such as to suppress electromagnetic interference and radio frequency interference, as well as transient suppression of electrostatic discharges and/or electromagnetic pulses. This invention also is directed to an improved interface between a pair of mating electrical components to isolate the components on either side of the connecting interface against electromagnetic interference, radio frequency interference and the like. Summary of the Invention A first object, therefore, of the invention is to provide a connector assembly with a new and improved environmental sealing system between the first electrical connector and another connector component, panel, case or the like. Another object of the invention is to provide a connector assembly with a new and improved electrical grounding interface between a pair of connector components to protect against radio frequency interference and the like. The first object is solved by the combination of features of claim 1. Claim 4 gives a solution to the second problem in connection with the first problem. In the exemplary embodiment of the invention, generally, an electrical connector assembly includes a first connector having a mating end with a seal-receiving channel, and a resilient seal received in the channel substantially surrounding the mating end of the connector. The seal includes a sealing groove having a given width and a given depth. The first connector is mateable along a mating axis with another connector component, such as within an aperture in a panel. The connector component includes a peripheral sealing lip insertable into the sealing groove of the first connector when the first connector and the connector component are mated along the mating axis. The invention contemplates that the sealing lip have a width greater than the width of the sealing groove and a length relative to the depth of the sealing groove such that the lip is spaced from the bottom of the groove when the connector and the connector component are in mated condition. Therefore, only sealing forces normal to the mating axis are effected between the sealing lip and the sealing groove. Consequently, as the first connector and connector component tend to loosen or separate because of environmental conditions, or as they tend to creep, bow or distort over time, the seal is maintained effective since there are no compressive sealing forces in the direction of the mating axis. Another feature of the invention is the provision of complementary interengaging abutment surfaces between the first connector and the connector component to limit the extent of insertion of the sealing lip into the sealing groove such that the lip remains spaced from the bottom of the groove when the first connector and the connector component are in mated condition. The invention contemplates that the abutment surfaces be of conductive material and include a pattern of point contacts to define a radio frequency seal therebetween. The complementary interengaging abutment surfaces extend substantially entirely about the mating interface of the first connector and the mating connector component. Additionally, the point contacts deform during mating to absorb variations in flatness of the mating surfaces and assure electrical contact between the surfaces. The point contacts also determine where contact between the two surfaces will be made ensuring that no large conductive gaps will be formed, which would allow EMI/RFR signals of a certain frequency to penetrate the electrical shielding seal. Still further, the invention contemplates the provision of a labyrinth path through the mating interface, including the radio frequency seal, to enhance the interference protection capabilities thereof. Specifically, the environmental sealing lip is defined by a first peripheral flange projecting from the connector component toward the connector assembly, and the complementary interengaging abutment surfaces include a second peripheral flange projecting from the connector assembly toward the connector component. The lip is located on one side of the second peripheral flange, and the connector component includes a third peripheral flange projecting therefrom toward the connector assembly on an opposite side of the second peripheral flanges. The flanges and the lip overlap each other normal to the mating axis to define a labyrinth path to enhance protection against radio frequency interference and the like. The labyrinth is a redundant signal attenuation feature which dramatically increases the path length for EMI/RFI signals trying to transit across the interface. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. Brief Description of the Drawings The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: FIG. 1 is a fragmented perspective view of an electrical connector assembly incorporating the environmental sealing system and EMF/RFI of the invention; FIG. 2 is a vertical section, on an enlarged scale, through the assembly of Fig. 1, the illustration being split to show the sealing system in inoperative and operative conditions; FIG. 3 is a section, on an enlarged scale, showing the environmental seal in unmated condition; FIG. 4 is a sectional view similar to that of Fig. 3, with the environmental seal in mated condition; FIG. 5 is a plan view of the pointed interengaging surface on the connector assembly housing; and FIG. 6 is a section through the pointed interengaging surface in engagement with a surface of the panel. Detailed Description of the Preferred Embodiment Referring to the drawings in greater detail, and first to Figs. 1 and 2, the invention is incorporated in an electrical connector assembly which includes a first multi-terminal filtered connector, generally designated 10, which is mateable with another connector component, generally designated 12. As disclosed herein, connector component 12 actually is a panel 14 having an elongate opening 16 through which a mating end 18 of the first connector 10 is inserted. The first connector assembly 10 includes a main connector part 20, and a subassembly 22. The subassembly 22 includes a housing 24 which mounts a ferrite filter block 26 through which tails 28 of a plurality of terminals project for insertion into appropriate holes in a printed circuit board 30 (Fig. 2), whereby the terminals tails 28 are soldered to appropriate circuit traces on the board or in the holes. Main connector part 20 includes a die cast housing 32 mounted to printed circuit board 30 by appropriate fastening means 34 (Fig. 2). The terminals have contact pins 36 projecting into mating end 18 of the connector 10, whereby the contact pins are engageable with complementary terminals (not shown) of an appropriate mating electrical connector inserted into mating end 18 in the direction of arrow "A". The contact pins of the terminals project through a flexible capacitor filter circuit 38 mounted to the back side of housing 32. The contact pins also project through a pair of seal blocks 40 (Fig. 1) which sandwich a base wall 42 of housing 32. The invention herein is directed to a sealing system between the first connector 10 and connector component 12 (panel 14) and which includes an environmental seal, generally designated 44, along with a radio frequency seal, generally designated 46. More particularly, referring to Figs. 3 and 4 in conjunction with Figs. 1 and 2, environmental seal 44 is provided by a seal-receiving channel 48 in housing 32, the channel being defined by mating end 18 and a forwardly projecting peripheral flange 49 of the housing. A resilient seal 50 is disposed within channel 48. The seal is generally U-shaped in cross-section to define a pair of legs 50a which form a sealing groove 52 therebetween. The sealing groove has a given width and a given depth of desired dimensions. Groove 52 and seal 50 surround mating end 18 of the connector assembly. Environmental seal 44 further includes a sealing lip 54 projecting rearwardly of panel 14 for insertion into sealing groove 52 along a mating axis which coincides with the mating direction "A" of main connector part 20 with its complementary connector. The upper half of Fig. 2 and Fig. 3 show sealing lip 54 about to be inserted into sealing groove 52 of seal 50. This is the unmated condition of the environmental seal corresponding to the unmated condition of connector assembly 10 with connector component 12 (i.e. panel 14). It can be seen that the width of sealing lip 54 is greater than the width of sealing groove 52. The bottom of Fig. 2 and Fig. 4 show sealing lip 54 inserted into sealing groove 52 and, with particular reference to Fig. 4, it can be seen that the sealing lip has compressed legs 50a of seal 50 in a direction normal or perpendicular to the insertion direction of the sealing lip, i.e. normal to mating axis "A". It also can be seen that the sealing lip has a length relative to the depth of the sealing groove such that the distal edge of the sealing lip is spaced from the bottom of the groove in fully mated condition. As a result, only sealing forces normal to the mating axis are effected between sealing lip 54 and sealing groove 52, as represented by arrows "B" in Fig. 4. With the construction and function of environmental seal 44, as particularly described in relation to the depiction of Fig. 4, it can be understood that should first connector 10 and connector component 12 (panel 14) creep, bow or distort under pressure, temperature or vibration conditions, the environmental seal afforded by the interengagement between sealing lip 54 and sealing groove 52 is not affected because there are no sealing forces parallel to the mating axis of the components. If the sealing lip were to bottom out in the sealing groove and the prescribed seal afforded by such a sealing means be relied upon, even the slightest creep between the interconnected components would cause the axially compressive sealing forces to lose their effectiveness. This could occur at any point surrounding the mating interface (i.e. mating end 18) of the first connector due to bowing or distortion of housing 32. With environmental seal 44 of the invention, which relies exclusively on sealing forces normal to the mating axis, the sealing function remains effective throughout a wide range of creeping, bowing or distortion of the connector assemblyi, particularly its elongated housing. Referring to Figs. 5 and 6 in conjunction with Figs. 1 and 2, radio frequency seal 46 is provided by a plurality of point contacts 60 formed along the entire distal edge of flange 49 of connector housing 32. It can be seen in Fig. 5 that point contacts 60 are arranged in rows, with the point contacts in adjacent rows being offset or alternating lengthwise of the edge of flange 49. The point contacts are located for engagement with a surface area 62 on the back side of panel 14, between sealing lip 54 and a further rearwardly projecting flange 64 of the panel. The top half of Fig. 2 and Fig. 3 show point contacts 60 and surface area 62 out of engagement. This represents the unmated condition of the radio frequency seal. The bottom half of Fig. 2 and Fig. 4 show point contacts 60 in abutting engagement with surface area 62. This represents the mated condition of the radio frequency seal corresponding to the mated condition of first connector 10 and connector component 12 (panel 14). It is contemplated that the panel, like housing 32, be of a die cast material, such as a magnesium casting. Therefore, point contacts 60 establish positive commoning between the connector housing and the panel surrounding the mating end 18 of connector 20 which projects through aperture 16 in the panel. The invention also contemplates the provision of a labyrinth path through radio frequency seal 44 (i.e. contact points 60) to enhance the protection capabilities of the seal against transmission therethrough of radio frequency or other interference waves. Specifically, referring to Fig. 4, it can be seen that flange 49 (which has contact points 60 along its distal edge) is located between sealing lip 54 and flange 64 which project rearwardly from panel 14. In other words, sealing lip 54, flange 49 and flange 64 all overlap each other normal to the mating axis of the components. In essence, it can be considered that point contacts 60 are "hidden" in a deadend location between sealing lip 54 and flange 64. Therefore, a labyrinth path c-c is provided to prevent direct interference waves from passing through the radio frequency seal. The interference waves must pass around flange 64, then around flange 49, and then around sealing lip 54 in order to flow through the interfacing area between main connector part 20 and connector component 12 (panel 14) effectively increasing the aspect ratio of the mating interface. The labyrinth is a redundant signal attenuation feature which dramatically increases the path length vs. the path width for EMI/RFI signals trying to transit across the interface.

Claims: A connector assembly, comprising a first electrical connector (10) mateable to another connector component (12) or panel (14) and the like, the first connector (10) including a housing (32) having a mating end (18) with a seal-receiving channel (48) and a resilient seal (50) received in the channel (48), and the other connector component (12) or pannel (14) including a sealing lip (54) insertable into the channel (48) when the connector (10) and the other connector component (12) or panel (14) are mated along a mating axis (A), characterized in that the seal (50) includes a sealing groove (52) having a given width and a given depth, said sealing lip (54) has a width greater than the width of the sealing groove (52) and a length relative to the depth of the sealing groove (52) such that the lip (54) is spaced from the bottom of the groove (52) when the first connector (10) and the connector component (12) or panel (14) are in mated condition, whereby only sealing forces normal to said mating axis (A) are effected between the sealing lip (54) and the sealing groove (52). The connector assembly as set forth in claim 1, wherein said resilient seal (50) is generally U-shaped in cross-section to define a pair of legs (50a) which form the sealing groove (52). The connector assembly as set forth in claim 1, including complementary interengaging abutment means (60, 62) between the connector assembly and the connector component to limit the extent of insertion of the sealing lip (54) into the sealing groove (52) such that the lip remains spaced from the bottom of the groove when the first connector and the other connector component (12) or panel (14) are in mated condition. The connector assembly as set forth in claim 3, wherein said complementary interengaging abutment means (60, 62) are of conductive material and include a pattern of point contacts (60) to define a radio frequency seal (46) therebetween. The connector assembly as set forth in claim 4, wherein said complementary interengaging abutment means (60, 62) extend substantially entirely about the mating end (18) of the housing (32) of the first connector (10). The connector assembly as set forth in claim 4, wherein said sealing lip (54) is defined by a first peripheral flange projecting from the other connector component (12) or panel (14) toward the connector (10), and said complementary interengaging abutment means (60, 62) include a second peripheral flange (49) projecting from the first connector (10) toward the other connector component (12) or panel (14), the flanges (49, 54, 64) overlapping each other normal to the mating axis (A) to define a labyrinth path through an interface area including said radio frequency seal (46). The connector assembly as set forth in claim 6, wherein said lip (54) is located on one side of said second peripheral flange (49), and the connector component (12) includes a third peripheral flange (64) projecting from the connector component (12) or panel (14) toward the first connector (10) on an opposite side of the second peripheral flange (49).

Inventors: COLLERAN STEPHEN A, CRANE BURKE J, FENCL DUANE M, KREHBIEL FRED LOVE, PLOCEK EDWARD J, COLLERAN, STEPHEN A., CRANE, BURKE J., FENCL, DUANE M., KREHBIEL, FRED LOVE, PLOCEK, EDWARD J.
Applicants: MOLEX INC, MOLEX INCORPORATED
Application year: 1993
Main classification: H01R13
IPC codes: H01R13