Patent Publication Number: US-7708593-B1

Title: Electrical connector having an encapsulant to seal the connector

Description:
BACKGROUND OF THE INVENTION 
   The subject matter herein relates generally to electrical connectors and, more particularly, for electrical connectors that are coupled with one or more cables. 
   Some known electrical connectors are joined with cables to electrically couple the connectors with the cables. For example, the connectors may include contacts that engage a mating device. The contacts electrically join the connector with the mating device. The cable typically includes one or more conductors enclosed by an insulative jacket extending along the interior of the cable throughout the length of the cable. The cable is connected with the connector with the conductors electrically terminated with the contacts to electrically couple the cable with the contacts. Thus, the connector electrically connects the mating device with the cable. Electrical power and/or signals may then be communicated between the mating device and the cable. In applications where the mating device is a solar module or panel, the connector may communicate electric potential or current from the solar module or panel to another mating device via the cable. 
   In some applications, the cables joined with the connectors may experience significant forces that pull the cable away from the housing of the connector. For example, environmental factors such as ice and snow may add weight to the cables joined to connectors on solar panels. This additional weight may pull the cables away from the connectors. If the cables are not affixed to the connectors in a sufficiently strong manner, the cables may become detached from the housings of the connectors. 
   Some known connectors include retention mechanisms that assist in preventing the cable from being separated from the connector housing. But, these retention mechanisms may be relatively large. For example, some known solar module connectors include pinch ring and nut combinations to secure cables to the connector housings. The pinch ring is a ring that is placed around the cable. The pinch ring includes several slots that permit the ring to be compressed down onto the cable. The nut is placed into the connector. The pinch ring is screwed into the nut to compress the pinch ring onto the cable and to couple the cable with the connector. The pinch ring is compressed around the cable when the nut is screwed down or tightened onto the connector. But, the size of the nut limits the size of the connector. That is, the size of the connector typically must be at least as large as the nut. As a result, the profile height of the connector is limited by the size of the nut. In certain applications, the size of the nut may require the connector to have a profile height that is too large. For example, the location in which some solar module connectors are required may be too small to fit a connector having a nut and pinch ring combination. 
   The interface between the cable and the housing at the opening provides a location where moisture can enter into the housing. In connectors that have too small of a profile to permit use of the pinch ring and nut combination, the cable/housing interface may be exposed to the atmosphere surrounding the connector. In conditions where the cable and housing experience changes in temperature, differences between coefficients of thermal expansion between the cable and the housing may result in a gap forming at the cable/housing interface. For example, the housing may be formed of a material that expands and contracts a greater distance than the material of the outer jacket of the cable over a common change in temperature. When the connector is used in environments experiencing relatively large temperature changes, the differences in coefficients of thermal expansion may cause a relatively large gap to be formed. The gap permits moisture to seep into the interior of the housing, where the moisture can electrically short the contacts or other electrical components of the housing. 
   Thus, a need exists for a connector assembly that affixes cables to connectors in such a manner to maintain a relatively small profile height of the connector while preventing moisture from entering into the housing. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In one embodiment, an electrical connector includes a housing, a cable, a contact and an encapsulant. The housing extends from a cable exit end to an opposite end along a longitudinal axis and from a mounting face to a top face along a vertical axis. The housing includes a cable opening that extends into the cable exit in a direction parallel to the longitudinal axis and a window extending from the housing from the top face toward the mounting face in a direction parallel to the vertical axis. The cable extends through the window and into the housing through the cable opening. The contact is held by the housing and is configured to electrically couple the cable with a mating device when the mounting face of the housing is mounted to the mating device. The encapsulant is disposed within the window to seal an interface between the cable and the housing. The encapsulant prevents ingress of moisture into the housing through the interface. 
   In another embodiment, another electrical connector is provided. The connector includes a housing, a cable, a contact and an encapsulant. The housing extends from a cable exit to an opposite end along a longitudinal axis and from a mounting face to a top face along a vertical axis. The housing frames a window extending through the housing from the top face to the mounting face. The cable is received into the housing through the cable exit. At least a portion of the cable is disposed within the window. The contact is held by the housing and is configured to electrically couple the cable with a mating device when the mounting face of the housing is mounted to the mating device. The encapsulant is disposed within the window to seal an interface between the cable and the housing. A web portion of the housing is disposed between the cable exit and the window to reduce a force that is imparted on the encapsulant to prevent separation between the encapsulant and at least one of the housing and the cable. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an electrical connector in accordance with one embodiment. 
       FIG. 2  a partially exploded view of the connector shown in  FIG. 1  in accordance with one embodiment. 
       FIG. 3  is another perspective view of the connector shown in  FIG. 1  in accordance with one embodiment. 
       FIG. 4  is another partially exploded view of the connector shown in  FIG. 1  in accordance with one embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a perspective view of an electrical connector  100  in accordance with one embodiment. The connector  100  is mounted to a mating device (not shown) to electrically couple the connector  100  and mating device. In the illustrated embodiment, the connector  100  is a photovoltaic connector that is mounted to a solar module (not shown). The connector  100  mounts to the solar module to electrically couple the connector  100  and the solar module such that the electric potential or current generated by the solar module may be drawn through the connector  100 . Cables  102  extending from the connector  100  communicate the electric potential or current generated by the solar module to an electrical load (not shown) and/or to another solar module. While two cables  102  are coupled with the connector  100  in the illustrated embodiment, a different number of cables  102  may be provided. Additionally, while the discussion herein focuses on photovoltaic connectors, one or more embodiments described below may be used as connectors for applications other than solar modules. 
   The connector  100  includes a housing  104  that extends between a cable exit  108  and an opposite end  106  along a longitudinal axis  110  and between opposite sides  112 ,  114  along a lateral axis  116 . The housing  104  also extends from a mounting face  118  to an opposite top face  120  along a vertical axis  122 . In the illustrated embodiment, the longitudinal axis  110 , lateral axis  116  and vertical axis  122  are perpendicular to each another. The mounting face  118  engages the solar module (not shown) when the connector  100  is mounted to the solar module. 
   In one embodiment, the housing  104   104  includes or is formed from a dielectric material. The housing  104  may be a rigid, unitary body that is molded from a dielectric material. By way of example only, the housing  104  may be molded from a polyester, such as polybutylene terephthalate (PBT). In one embodiment, the housing  104  is formed of 30% glass fiber filled PBT. However, other materials and composites may be used to form the housing  104 . The housing  104  may be formed by overmolding the housing  104  over portions of the cables  102 . Alternatively, the housing  104  may be molded with the cables  102  later loaded into the housing  104  through the cable exit  108 . 
   The cables  102  include one or more conductors (not shown) that are electrically coupled with contacts  224  (shown in  FIG. 2 ) held in the housing  104 . The conductors are circumferentially enclosed in an insulative sheath or jacket  124 . The jacket  124  includes or is formed from a dielectric material. For example, in one embodiment, the jacket  124  may be formed from a flexible cross-linked polyolefin material. 
   The connector  100  includes a front end cover  126  and a rear end cover  128  in the illustrated embodiment. As described below, the front end cover  126  encloses a contact window  222  (shown in  FIG. 2 ) in the housing  104  and the rear end cover  128  encloses cable windows  206  (shown in  FIG. 2 ) in the housing  104 . The front end cover  126  and rear end cover  128  enclose the contact window  222  and cable windows  206  to enclose an encapsulant  400  (shown in  FIG. 4 ) that is disposed within the cable windows  206  and/or the contact window  222 . Alternatively, the front and/or rear end covers  126 ,  128  are not included in the connector  100 . 
     FIG. 2  a partially exploded view of the connector  100  in accordance with one embodiment. As shown in  FIG. 2 , the cables  102  include cable connectors  200 ,  202 . The cable connector  202  is a plug connector and the cable connector  200  is a receptacle connector. The cable connectors  200 ,  202  mate with cable connectors  200 ,  202  on an external device (not shown), such as another connector  100 , a solar module, an electrical load, and the like, to electrically join the connector  100  and the mating device (not shown) to which the connector  100  is mounted with the external device. 
   The cable windows  206  define openings into the housing  104  that extend from the top face  120  toward the mounting face  118  in directions parallel to the vertical axis  122 . While two cable windows  206  are shown in  FIG. 2 , alternatively a single cable window  206  may be used. In one embodiment, the cable windows  206  extend completely through the housing  104  from the top face  120  to the mounting face  118 . The housing  104  frames the cable windows  206  such that the housing  104  surrounds the cable windows  206  from the top face  120  to the mounting face  118 . As shown in  FIG. 2 , the rear end cover  128  is placed over the cable windows  206  to enclose the cable windows  206 . A web portion  218  of the housing  104  includes the section of the housing  104  that is disposed between the cable exit  108  and the cable windows  206 , between the mounting face  118  and the top face  120 , and between the sides  112 ,  114  of the housing  104 . 
   The housing  104  includes inner walls  208 ,  210  that oppose one another across each of the cable windows  206 . A portion  216  of each of the cables  102  is disposed in the cable windows  206  between the inner walls  208 ,  210  of each cable window  206 . In the illustrated embodiment, each inner wall  208  includes a cable opening  212  through which the cables  102  extend. The cable openings  212  may be formed by the overmolding of the housing  104  onto the cables  102 . The cable openings  212  are aligned with the longitudinal axis  110  of the housing  104 . For example, the cables  102  may extend into the housing  104  through the cable openings  212  in a direction that is oriented approximately parallel to the longitudinal axis  110 . The cable openings  212  may have a size that is approximately the same as the cables  102 . For example, the cables  102  may have circular cross-sections and the cable openings  212  may be circular in shape. The diameters of the cable openings  212  may be approximately the same size as, or slightly smaller than, the diameters of the cables  102 . 
   The housing  104  includes additional cable openings  214  disposed in the cable exit  108  of the housing  104  through which the cables  102  extend. Similar to the cable openings  212 , the cable openings  214  may be formed when the housing  104  is overmolded onto the cables  102 . As shown in  FIG. 2 , each of the openings  214  extends through the housing  104  from the cable exit  108  to the corresponding inner wall  210  in a direction that is oriented approximately parallel to the longitudinal axis  110 . Similar to the cable openings  212 , the openings  214  may have an approximately circular shape with diameters that are approximately the same as the diameters of the cables  102 . In the illustrated embodiment, the openings  214  are axially aligned with the cable openings  212  such that the cables  102  are loaded through the openings  214  and into the cable openings  212  in directions that are oriented approximately parallel to the longitudinal axis  110 . For example, center axes  220  of the cables  102  are oriented approximately parallel to the longitudinal axis  110  within the cable windows  206 . 
   The housing  104  includes the contact window  222  in the illustrated embodiment. The contact window  222  defines an opening into the housing  104  that extends from the top face  120  toward the mounting face  118  in a direction that is parallel to the vertical axis  122 . In one embodiment, the contact window  222  extends completely through the housing  104  from the top face  120  to the mounting face  118 . The housing  104  frames the contact window  222  such that the housing  104  surrounds the contact window  222  from the top face  120  to the mounting face  118 . One or more of the contacts  224  are held by the housing  104  and extend into the contact window  222 . The contact window  222  may provide visual access to the contacts  224  to ensure that the contacts  224  engage mating contacts (not shown) of a mating device (not shown) when the connector  100  is mounted to the mating device. For example, the contacts  224  may be soldered or welded to the mating contacts. 
     FIG. 3  is another perspective view of the connector  100  in accordance with one embodiment. The view shown in  FIG. 3  illustrates the mounting face  118  of the connector  100 . In the illustrated embodiment, the cable windows  206  and the contact window  222  extend through the housing from the mounting face  118  to the opposite face  120 . The contacts  224  extend into the contact window  222  from the housing  104 . While two contacts  224  are shown, a different number of contacts  224  may be provided. 
     FIG. 4  is another partially exploded view of the connector  100  in accordance with one embodiment. An encapsulant  400  is loaded into the cable windows  206  and the contact window  222 . For example, a flexible potting material may be fluidly dispensed into the cavities defined by the cable windows  206  and the contact window  222 . The encapsulant  400  may include one or more flexible materials such as, by way of example only, a room temperature vulcanized (RTV) silicone or other silicone-based material. In one embodiment, the encapsulant  400  is formed of a material that is more flexible than the housing  104 . Alternatively, the encapsulant  400  may include or be formed from a rigid material. For example, the encapsulant  400  may be formed of the same material that the housing  104  is molded from. The same or different potting materials may be used as the encapsulant  400  in two or more of the cable windows  206  and contact window  222 . The encapsulant  400  may be or include an adhesive material. For example, the encapsulant  400  may chemically and/or physically bond or adhere to the housing  104  and/or cables  102  inside the cable windows  206  when the encapsulant  400  cures. 
   The encapsulant  400  may be fluidly dispensed into the cable windows  206  and the contact window  222  after mounting the connector  100  to a mating device (not shown), such as a solar module. For example, the encapsulant  400  may be loaded into the cable windows  206  and/or the contact window  222  when the encapsulant  400  is in a state that allows the encapsulant  400  to flow like a liquid. The back end cover  128  and the front end cover  126  (shown in  FIG. 1 ) may then be placed over the cable windows  206  and the contact window  222 . The encapsulant  400  then cures in the cable windows  206  and in the contact window  222 . The encapsulant  400  may adhere to the front end cover  128  and the rear end cover  126  to secure or assist in securing the front end cover  128  and the rear end cover  126  to the housing  104 . 
   The encapsulant  400  in the cable windows  206  seals the interface between the cables  102  and the housing  104 . For example, the encapsulant  400  may seal the interface between the cables  102  and each of the inner walls  208 ,  210  (shown in  FIG. 2 ) of the housing  104 . The encapsulant  400  seals the interfaces to prevent ingress of moisture into the housing  104 . The sealing of the encapsulant  400  around the periphery of the cables  102  at the housing  104  prevents moisture from moving through the cable openings  212  (shown in  FIG. 2 ) and into the housing  104 . 
   The encapsulant  400  seals the interface between the cables  102  and the housing  104  during changes in temperature of the connector  100 . For example, the outer jackets  124  of the cables  102  may have a coefficient of thermal expansion (CTE) that differs from the CTE of the housing  104 . In one embodiment, the cables  102  have a CTE that is less than a CTE of the housing  104 . The lower CTE of the cables  102  causes the cables  102  to expand or contact a smaller distance than the housing  104  in one or more directions for a common change in temperature. The different amounts of expansion and contraction between the cables  102  and the housing  104  for a common temperature change may result in a gap being formed between the cables  102  and the housing  104  at the interfaces between the cables  102  and the housing  104 . For example, a gap may form at the interface between the cables  102  and the housing  104  at the cable openings  212 . The encapsulant  400  seals this interface and any gap that forms at the interface to prevent ingress of moisture into the housing  104  through this interface. 
   In one embodiment, the encapsulant  400  has a CTE that is less than a CTE of the housing  104  and is greater than a CTE of the outer jackets  124  of the cables  102 . For example, for a common change in temperature, the CTE of the encapsulant  400  may cause the encapsulant  400  to expand and contract a greater distance than the outer jackets  124  of the cables  102  but a lesser distance than the housing  104  in one or more directions. The CTE of the encapsulant  400  may be closer in value to a CTE of the housing  104  than to a CTE of the outer jackets  124 . For example, the CTE of the encapsulant  400  may more closely match a CTE of the housing  104  than a CTE of the outer jackets  124 . As described above, the encapsulant  400  may be a flexible material relative to the housing  104 . The flexible characteristic of the encapsulant  400  and the CTE of the encapsulant  400  may enable the encapsulant  400  to maintain the seal at the interface between the cables  102  and the housing  104  to prevent a gap from forming over a change in temperature that would otherwise form a gap at the interface. For example, over a common temperature change, a gap would form at the cable/housing interface at the cable openings  212  if the encapsulant  400  was not disposed in the cable windows  206 , while no gap would form at the interface if the encapsulant  400  is disposed in the cable windows  206 . 
   In one embodiment, the encapsulant  400  may have an insufficiently low UV rating to withstand being exposed to sunlight. For example, the encapsulant  400  may break down and fail to seal the interfaces between the cables  102  and the housing  104  after being exposed to UV light for a sufficiently long time. In order to protect the encapsulant  400  from exposure to UV light, the rear end cover  128  and front end cover  126  may be placed over the cable windows  206  and the contact window  222 , respectively. The front end cover  126  and rear end cover  128  may be formed of UV-rated materials that block all or substantially all of the UV light that is incident upon the connector  100 . In one or more embodiments where the connector  100  is used with a solar module in an outside environment, the UV-rated front and rear end covers  126 ,  128  can protect the encapsulant  400  from UV light. 
   The web portion  218  of the housing  104  prevents the encapsulant  400  from being separated from the housing  104  at the interfaces between the encapsulant  400  and each of the inner walls  208 ,  210  (shown in  FIG. 2 ). The web portion  218  also may prevent the encapsulant  400  from being separated from the cables  102  within the windows  206 . During mounting of the connector  100  onto a mating device (not shown) and/or use of the connector  100 , one or more of the cables  102  may be moved in directions that are angled with respect to the longitudinal axis  110 . For example, the cables  102  may be moved in one or more transverse directions  402 ,  404  and vertical directions  406 ,  408  that are angled with respect to the longitudinal axis  110 . Without the web portion  218 , movement of the cables  102  in the transverse direction  402 ,  404  may impart a force on the encapsulant  400  at the interfaces between the encapsulant  400 , the inner walls  208 ,  210 , and the cable portions  216 . For example, movement of the cables  102  may cause movement of the encapsulant  400  with respect to the housing  104 . Movement of the encapsulant  400  relative to the housing  104  may cause separation between the encapsulant  400  and the housing  104 . The forces imparted on the encapsulant  400  may cause the encapsulant  400  to separate from one or more of the inner walls  208 ,  210  and/or from the cable portions  216 . For example, the force could separate the encapsulant  400  from the inner wall  208  and expose the interface between the cables  102  and the housing  104  at the cable openings  212 . 
   The web portion  218  may isolate the encapsulant  400  from the forces that could separate the encapsulant  400  from the interfaces between the encapsulant  400  and the housing  104  and between the encapsulant  400  and the cables  102 . For example, the web portion  218  can prevent or reduce movement of the cables  102  from imparting forces on the encapsulant  400  by isolating the portions  216  (shown in  FIG. 2 ) of the cables  102  from movement of the cables  102  outside of the housing  104 . The web portion  218  permits the sections of the cables  102  that are located outside of the housing  104  and the cable windows  206  to be moved in directions angled with respect to the longitudinal axis  110  while preventing the portions  216  of the cables  102  within the housing  104  to be moved. As the portions  216  of the cables  102  do not move, the portions  216  do not cause the encapsulant  400  to move or to impart any force on the interfaces at the encapsulant  400 , the inner walls  208 ,  210  or the cable portions  216 . 
   It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means—plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.