Patent Publication Number: US-8529278-B2

Title: Waterproof electrical connector and waterproof electrical connector assembly method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the filing date under 35 U.S.C. §119(a)-(d) of Japanese Patent Application No. JP 2010-178451 filed on Aug. 9, 2010. 
     FIELD OF INVENTION 
     The present invention relates to an electrical connector that electrically connects a wire to a mating connector, and more particularly relates to a waterproof electrical connector. 
     BACKGROUND 
     Conventionally, among electrical connectors, waterproof connectors which prevent water from entering the connecting portion with a mating connector are known. In air bag systems of automobiles an electrical signal is sent to the ignition device to cause an explosion, and the gas generated from the explosion fills the air bag. The wiring which sends the electrical signal in the air bag system is connected to the mating connector on the ignition device through an electrical connector. Recently, air bag devices have come to be installed not only in the steering portion in the interior of automobiles, but also, inside the doors as a curtain air bag or a side air bag. Since condensation or the like is more likely to be formed inside the doors compared with the interior, the connectors used inside the doors needs to be waterproof, which includes being not only “watertight” to prepare for the possibility of water coming in direct contact therewith, but also being “airtight” to prepare for the possibility of dew condensation occurring inside the electrical connectors. 
     As one of the aforementioned electrical connectors, for example, as shown in  FIG. 4 , a waterproof electrical connector  1  has been proposed in which an outer side of an insulative housing  2  is covered with a body  8  by melt molding in a state in which the insulative housing  2  holds electric wires  6  that are led out there from (for example, see Japanese Patent Laid-Open No. 2009-200010). 
     In the waterproof electrical connector  1 , as shown in  FIG. 5 , the insulative housing  2  comprises a main housing  3  and a cover housing  4  which are both made of an insulating synthetic resin. The main housing  3  has a fitting section  5  that receives a contact, and an electric wire end covering section  7  that projects in a direction in which the electric wires  6  project, and that receives a connecting portion between a contact and the electric wires. Further, the fitting section  5  of the main housing  3  includes an opening for inserting a contact from an end on an opposite side to a side facing the mating connector. The cover housing  4  is positioned to block off the opening. The cover housing  4  and the electric wire end covering section  7  of the main housing  3  hold an electric wire connection portion of the contact and the electric wires  6 . 
     The body  8  covers a part of the main housing  3  and the entire surface of the cover housing  4  to cover both a boundary portion between the main housing  3  and the cover housing  4 , and portions holding the electric wires  6 . 
     A seal member  9  is integrally arranged on an outer circumferential face in the vicinity of the tip of the main housing  3 . The seal member  9  is formed by, for example, insert-molding silicone rubber onto the outer circumferential face of the already-formed main housing  3 . Further, the seal member  9  may also be formed simultaneously and integrally with the main housing  3  by two-color injection molding. 
     However, according to the above described waterproof electrical connector  1 , there is a problem in that the body  8  becomes detached from the main housing  3  and the cover housing  4 . When the body  8  detached, waterproofness of the waterproof electrical connector  1  is compromised. 
     One factor that causes the detachment of the body  8  is a result of oil included in the seal member  9 . The oil is provided on the distal end portion of the main housing  3 , and when a worker manually handles the main housing  3  and the cover housing  4  during the process of manufacturing and assembling the waterproof electrical connector  1 . The oil adheres to portions to which the body  8  is to be attached(for example, portions denoted by reference character A in  FIG. 5A ) of the main housing  3  and the cover housing  4 . 
     SUMMARY 
     The present invention has been accomplished in view of the above described technical problems, and an object of the present invention is to provide a waterproof electrical connector that can prevent the adherence of oil or the like to an attachment portion of a body to thereby prevent the peel-off of the body and make the waterproofness more reliable, as well as an assembly method of the waterproof electrical connector. 
     The connector includes a main housing, a cover housing, a contact, and a body. The main housing includes a mating protrusion, a fitting section, and a head portion. The contact includes a contacting portion that is received in the fitting section and an electric wire connection portion that connects to one end of an electric wire. The body covers at least a boundary portion between the main housing and the cover housing. The main housing further includes an outer circumferential wall positioned on an outer circumferential side of the boundary portion between the main housing and the cover housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1A  is a perspective view of a squib connector according to the invention viewed from a face side opposite to the fitting face; 
         FIG. 1B  is a perspective view of the squib connector viewed from a fitting face side; 
         FIG. 2A  is a perspective view of the squib connector viewed from the surface side opposite to the fitting face in the state; 
         FIG. 2B  is a perspective view of the squib connector viewed from the fitting face side in a state before a body is formed on the squib connector; 
         FIG. 3  is a sectional view of the squib connector; 
         FIG. 4A  is a perspective view of a known squib connector as seen from the side of a head portion thereof; 
         FIG. 4B  is a perspective view of the known squib connector as seen from a mating surface side; 
         FIG. 5A  is a perspective view of the known squib connector as seen from a head portion side of a main housing; and 
         FIG. 5B  is a perspective view of the known squib connector as seen from a mating surface side of the main housing. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     The present invention is described in detail hereunder based on an embodiment that is illustrated in the attached drawings. 
     With reference to  FIG. 1A and 1B , the outer appearance of a squib connector (waterproof electrical connector)  10  according to the invention is shown. 
     The squib connector  10  connects electric wires  100  to a mating connector (not shown) provided in an ignition device of a vehicle airbag. 
     The squib connector  10  includes an insulative housing  11 , a seal member  17 , and a body  60 . 
     As shown in  FIG. 2 , the insulative housing  11  comprises a main housing  12  and a cover housing  14  that are both made of an insulating synthetic resin. 
     As shown in  FIG. 3 , a contact  15  that is connected to an end of each of the insulatively-coated electric wires  100  and a ferrite core  16  for noise absorption are provided inside the insulative housing  11  of the squib connector  10 . 
     In the embodiment shown, the contact  15  is a female contact that mates with a male contact of the mating connector, and is a member formed by stamping, bending, and plating a metal plate. The contact  15  is approximately L-shaped, and includes a contacting portion  51  which contacts the male contact of the mating connector, and an electric wire connection portion  52  that connects to one end of the electric wire  100 . The electric wire connection portion  52  has a core wire crimping portion  52   a  which crimps a core wire of the electric wire  100 , and an insulating coating crimping portion  52   b  that crimps an insulating coating of the electric wire  100 . 
     The ferrite core  16  has a cylindrical shape, and is positioned on an outer circumferential side of the contacting portion  51  of the contact  15 . The ferrite core  16  prevents electromagnetic noise from infiltrating from outside, and also prevents the leakage of electromagnetic noise to outside. 
     The main housing  12  of the insulative housing  11  includes a head portion  12 A and a columnar mating protrusion  12 B that extends in one direction from the head portion  12 A and mates with a mating receiving section of the mating connector. 
     A contact receiving chamber  34  that extends in the axial direction of the mating protrusion  12 B is formed in the head portion  12 A and the mating protrusion  12 B. The head portion  12 A side of the contact receiving chamber  34  is open. The contacting portion  51  of the contact  15  and the ferrite core  16  are inserted into and received inside this opening  34   a  in the contact receiving chamber  34 . 
     The tip of the mating protrusion  12 B includes a connection receiving passageway  35  through which the contact receiving chamber  34  communicates with outside. When connecting the squib connector  10  to the mating connector, the male contact of the mating connector is inserted into the contact receiving chamber  34  through the connection receiving passageway  35  and comes in contact with the contact  15 . 
     As shown in  FIG. 2 , a lock  31  is positioned on the outer circumferential face of the mating protrusion  12 B of the main housing  12 . The lock  31  prevents the mating protrusion  12 B from coming loose from the contact-receiving concavity when the mating protrusion  12 B is inserted into the contact-receiving concavity up to a predetermined position. The lock  31  is integrally formed with the main housing  12 . 
     The head portion  12 A includes an electric wire end covering section (supporting portion)  20  that protrudes in an orthogonal direction to the mating direction with the mating connector. The electric wire end covering section  20  receives the electric wire connection portion  52  that is connected to one end of each electric wire  100 , that is led out in an orthogonal direction to the mating direction with the mating connector. 
     The head portion  12 A includes a flange portion  24  that projects to the outer circumferential side at a position that is separated by a predetermined dimension on the mating protrusion  12 B side from a top portion  29   p  of a cylindrical wall  29  forming the opening of the contact receiving chamber  34 . The flange portion  24  is continuously formed in the circumferential direction of the head portion  12 A, excluding a portion at which the electric wire end covering section  20  is formed. 
     An outer circumferential wall  25  that rises towards an opposite side to the mating protrusion  12 B is formed at a peripheral portion of the flange portion  24 . The outer circumferential wall  25  includes a top portion  12   p  that is located at a position that is further on the opposite side to the protruding direction of the mating protrusion  12 B than the top portion  29   p  of the cylindrical wall  29  in the main housing  12 . The top portion  12   p  is preferably formed to protrude towards the opposite side to the mating protrusion  12 B to a level equal to or more than a top face  14   a  of the cover housing  14 . 
     A material receiving passageway  26  that penetrates the outer circumferential wall  25  in the thickness direction thereof is formed in at least one place in the outer circumferential wall  25 . The material receiving passageway  26  is used as a gate hole  27  for injecting a material in a molten state into a mold to form a body  60  as described later. Although the gate hole  27  may be formed at any position, preferably the gate hole  27  is formed on a side that is away from the electric wire end covering section  20 . 
     The outer circumferential wall  25  may include a plurality of the material receiving passageways  26 . In this case, it is preferable that the material receiving passageways  26  are formed with spaces there between in the circumferential direction of the outer circumferential wall  25 . 
     Two end portions  25   a  of the outer circumferential wall  25  are positioned to extend in parallel with the direction in which the electric wire end covering section  20  extends. Mating depressions (second recesses)  28  are formed on the mating protrusion  12 B side of the two end portions  25   a  and  25   a  and face the electric wire end covering section  20 . The body  60  meshes with the mating depression  28  to thereby prevent the peel-off of the body  60 . 
     In the head portion  12 A of the main housing  12 , the cover housing  14  of the insulative housing  11  has an opening covering portion  43  that covers the opening  34   a  for inserting the contact  15  into the contact receiving chamber  34 . An outer circumferential portion (overhanging portion)  43   a  of the opening covering portion  43  extends in a cylindrical shape from the flange portion  24  of the head portion  12 A of the main housing  12 , and has an outer diameter that is larger than the cylindrical wall  29  forming the opening of the contact receiving chamber  34 . The cylindrical wall  29  includes a latching projection  29   a  that protrudes to the outer circumferential side and that is located on an opposite side to the electric wire end covering section  20 . The opening covering portion  43  includes a lock portion  44  that extends to the flange portion  24  side, and the lock portion  44  having a lock hole  44   a  that engages with the latching projection  29   a . Thus, the cover housing  14  is latched to the head portion  12 A of the main housing  12  on an opposite side to the electric wire end covering section  20 . 
     The cover housing  14  also includes an electric wire end covering portion  40  that covers the electric wire end covering section  20  of the main housing  12 . A fastener  41  is formed at both ends of the electric wire end covering portion  40 . The fasteners  41  secure the cover housing  14  from displacement from the head portion  12 A by engaging with a latching claw  20   a  formed in the electric wire end covering section  20 . 
     The insulative housing  11  holds the electric wire connection portion  52  of the contact  15  and the electric wires  100  between the electric wire end covering section  20  of the main housing  12  and the electric wire end covering portion  40  of the cover housing  14 . 
     The body  60  is formed to be integral with the insulative housing  11  through molding. At that time, the body  60  is formed using employing the material receiving passageway  26  formed in the outer circumferential wall  25  as the gate hole  27 , and injecting material in a molten state into a mold from the gate hole  27 . 
     The body  60  is formed by taking the outer circumferential wall  25  as a mold for the outer circumferential side thereof, and filling the material into the inner side thereof up to a level that is the same as an upper end face of the outer circumferential wall  25 . After the body  60  has hardened, a portion thereof that has been filled into the material receiving passageway  26  is engaged with the outer circumferential wall  25 . If a material receiving passageway  26  other than the gate hole  27  is also formed, the body  60  also enters into the material receiving passageway  26  and engages therewith. Thus, the peel-off of the body  60  on a side that is away from the electric wire end covering section  20  is prevented. 
     Further, on the electric wire end covering section  20  side, the body  60  interconnects with the mating depression  28  formed in the two end portions  25   a  and  25   a  of the outer circumferential wall  25  to thereby prevent the peel-off of the body  60  on the electric wire end covering section  20  side. 
     Furthermore, in the cover housing  14  that is latched to the head portion  12 A of the main housing  12 , the outer circumferential portion  43   a  of the opening covering portion  43  projects more to the outer circumferential side than the cylindrical wall  29  of the head portion  12 A of the main housing  12 . The body  60  engages with the projecting portion of the opening covering portion  43 , and thus the peel-off of the body  60  is also prevented thereby. 
     The body  60  formed in this manner covers a portion of the main housing  12  and the entire surface of the cover housing  14 , covering both a boundary portion between the main housing  12  and the cover housing  14  and a portion that holds the led-out electric wires  100 . That is, the insulating coating of each of the electric wire  100  is attached to the insulative housing  11  by the body  60 . 
     For example, according to one embodiment, a polyamide hot melt material or a polyester hot melt material is used as the material for the body  60 . The material for the body  60  is not limited to the aforementioned materials, and any material may be used as long as the material can be molded to be integral with the insulative housing  11  by molding, can be molded at a low pressure in a short period of time, and has a high affinity for a resin material that forms the insulative housing  11  and does not adhere to the mold. 
     The seal member  17  is integrally arranged on an outer circumferential face in the vicinity of the tip of the mating protrusion  12 B. The seal member  17  has an annular shape to surround a part of an outer circumferential face, and lip portions  17   a  are formed on the outermost periphery thereof. The lip portions  17   a  protrude further to the outer circumferential side than the outer circumferential face of the mating protrusion  12 B. The outer diameter of the seal member  17  is larger than the inner diameter of the contact-receiving concavity of the mating connector. That is, the seal member  17  is formed to be in close and elastic contact with an inner wall of the contact-receiving concavity when the mating protrusion  12 B is inserted into the contact-receiving concavity. 
     The seal member  17  is formed, for example, by insert-molding of silicone rubber onto an outer circumferential face of the already-formed mating protrusion  12 B of the main housing  12 . The silicone rubber adheres to the main housing  12  in the course of the insert-molding process, and thereby forms the seal member  17  that is integrated with the main housing  12 . 
     The seal member  17  may also be formed simultaneously and integrally with the main housing  12  by two-color injection molding. 
     The squib connector  10  is manufactured as follows. First, the ferrite core  16  and the contact  15  that is connected to the electric wires  100  are inserted into the contact receiving chamber  34  of the main housing  12  and accommodated therein. 
     Next, the cover housing  14  is mounted to the main housing  12  to block off the opening  34   a  of the contact receiving chamber  34 . 
     Thereafter, the insulative housing  11  is set inside a mold, the material for the body  60  is filled in a molten state into the inner side of the outer circumferential wall  25  from the gate hole  27  formed in the outer circumferential wall  25 , and the material is hardened to obtain the squib connector  10 . 
     In the above described squib connector  10 , the outer circumferential wall  25  is provided to surround the outer circumferential side of portions at which the body  60  is to be attached to the main housing  12  and the cover housing  14 . Therefore, it is possible to prevent a worker from contacting the attachment portions of the body  60  with a finger or the like when assembling the squib connector  10 . Thus, oil contained in the seal member  17  can be prevented from adhering to the body  60 , and the body  60  can be reliably attached. 
     Further, the outer circumferential portion of the body  60  is not exposed because the outer circumferential wall  25  is provided in the head portion  12 A of the main housing  12 . Therefore, it is possible to prevent an external force from being applied to the body  60  and causing the peel-off of the body  60 . 
     Further, even if an external force is applied from the side of the electric wires  100 , the peel-off of the body  60  can be reliably prevented by means of the friction between the inner circumferential face of the outer circumferential wall  25  and the body  60 , the engagement between the material receiving passageway  26  of the outer circumferential wall  25  and the body  60  that has entered therein, the engagement between the mating depression  28  of the outer circumferential wall  25  and the body  60 , and the engagement between the outer circumferential portion  43   a  of the opening covering portion  43  of the cover housing  14  and the body  60  on the inner circumferential side of the outer circumferential wall  25 . 
     Thus, displacement of the body  60  can be prevented, and the waterproofness of the squib connector  10  can be made more reliable. 
     Although the present embodiment describes an example in which the waterproof electrical connector of the invention is the squib connector  10 , the invention is not limited thereto, and can also be applied to a waterproof electrical connector used for other purposes. 
     Further, although the present embodiment describes the detailed structure of respective portions of the main housing  12  and the cover housing  14  constituting the squib connector  10 , the configuration of portions other than the flange portion  24 , the outer circumferential wall  25 , and the body  60  may correspond to the relevant configurations described in Japanese Patent Laid-Open No. 2009-200010. Furthermore, any structure may be adopted as long as the outer circumferential wall  25  is positioned in the main housing  12 , and the body  60  is positioned on the inner side of the outer circumferential wall  25 . 
     In addition, although the present embodiment adopts a configuration in which the outer circumferential wall  25  includes the material receiving passageway  26 , and the body  60  is engaged with the outer circumferential wall  25  by the entry of the material for the body  60  into the material receiving passageway  26 , the number and shape of the material receiving passageways  26  are not limited in any way. Further, a configuration may be adopted in which a recess or groove, and not the material receiving passageway  26 , is formed in the inner wall face of the outer circumferential wall  25 . 
     Furthermore, with respect to the outer circumferential wall  25 , a configuration may be adopted in which the outer circumferential wall  25  is cut off after forming the body  60 . 
     It will be understood that, in addition to the foregoing, elements of the configuration described according to the above embodiment can be selectively omitted or adopted, or the configuration can be appropriately changed to another configuration without departing from the spirit of the invention.