Patent Publication Number: US-2017373480-A1

Title: Electrical Connector

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the filing date under 35 U.S.C. §119(a)-(d) of Japanese Patent Application No. 2016-125746, filed Jun. 24, 2016. 
     FIELD OF THE INVENTION 
     The present invention relates to an electrical connector and, more particularly, to an electrical connector having a light waterproof performance. 
     BACKGROUND 
     In an electrical connector, a rubber seal ring that is separate from a housing is interposed between, for example, a male housing and a female housing, so as to prevent water from entering the electrical connector. The electrical connector, including this seal ring, is used at a location where water is more likely to enter. 
     In addition to the seal ring, a technique for providing a housing with an inclined surface, so as to discharge water which has entered a connector, has been proposed. For example, JP2011-150895A proposes a technique for forming an inclined surface on an inner surface of a case so that water which has entered a gap between the case and the connector can flow toward an opening side. JP2011-150895A discloses that a groove extending toward the opening side is formed in the inclined surface and drainage can be improved due to capillary action generated by the groove. 
     The inclined surface disclosed in JP2011-150895A is provided between a hood of the case and the connector so as to discharge the water which has entered the connector. However, the inclined surface cannot prevent the water from entering the connector. That is, it is understood that the structure disclosed in JP2011-150895A includes a seal ring, which allows water to enter until the water reaches the range of the seal ring. 
     The provision of the seal ring is advantages in terms of waterproofing, but has a problem that, for example, the number of parts increases. Accordingly, in the electrical connector that is placed at a position where water is less likely to fall, there is no need to provide a seal ring and it is sufficient to ensure a certain level of waterproofing or light waterproofing. 
     In general, water falls onto an upper part of an electrical connector in the vertical direction. Accordingly, the water received on the upper part of the electrical connector is highly likely to enter the gap between the hood and the connector. 
     SUMMARY 
     An electrical connector, constructed in accordance with the present invention, is adapted to be mated in a receiving space formed in a hood of a mating connector. This electrical connector has a housing which has an upper wall, a bottom wall, and side walls. The upper wall has an inclined surface with an inclination angle of more than 90° and a stepped surface. 
     An electrical connector assembly, constructed in accordance with the present invention, includes a first electrical connector and a mating electrical connector. The first electrical connector has a housing which has an upper wall, a bottom wall, and side walls. The upper wall has an inclined surface with an inclination angle of more than 90° and a stepped surface. The mating electrical connector has a hood having a receiving space in which the housing of the first electrical connector is positioned with the inclined surface of the upper wall of the housing of the first connector outside the hood and the stepped surface of the upper wall of the housing of the first connector outside the hood and the stepped surface outside the hood. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  and  FIG. 1B  are perspective views of an electrical connector according to an embodiment of the present invention,  FIG. 1A  showing the electrical connector as viewed from a bottom side thereof and  FIG. 1B  showing the electrical connector as viewed from a top side thereof; 
         FIG. 2A  and  FIG. 2B  are sectional views of the electrical connector according to the  FIG. 1A  and  FIG. 1B  embodiment,  FIG. 2A  being a longitudinal sectional view and  FIG. 2B  being a sectional view as viewed along a direction different from that in  FIG. 2A ; 
         FIG. 3A ,  FIG. 3B , and  FIG. 3C  are sectional diagrams useful in explaining a water stop function of the electrical connector according to the  FIG. 1A  and  FIG. 1B  embodiment,  FIG. 3A  showing an example in which an inclination angle θ is an obtuse angle,  FIG. 3B  showing an example in which the inclination angle θ is a right angle, and  FIG. 3C  showing an example in which the inclination angle θ is two right angles; 
         FIG. 4A  and  FIG. 4B  are sectional views showing other examples of the electrical connector according to the  FIG. 1A  and  FIG. 1B  embodiment; and 
         FIG. 5A  is a sectional view showing another example of the electrical connector according to the  FIG. 1A  and  FIG. 1B  embodiment and  FIG. 5B  is a sectional view showing still another example of the electrical connector according to the  FIG. 1A  and  FIG. 1B  embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Embodiments of the present invention will be described below with reference to the accompanying drawings. 
     As shown in  FIGS. 2A and 2B , an electrical connector  10  according to this embodiment of the present invention is fixed to, for example, a printed wiring board and is used in a state of an electrical connector assembly  1  in which the electrical connector  10  is mated with a mating connector  30 . Note that the structures of the electrical connector  10  and the mating connector  30  are simplified for ease of explanation of a water stop function of this embodiment of the present invention. 
     [Electrical Connector  10 ] 
     Referring to  FIGS. 1A and 1B  and  FIGS. 2A and 2B , the electrical connector  10  includes a housing  11  and contacts. The housing  11  is integrally formed of resin having an electrical insulation. The contacts are formed of a material having high conductivity and elasticity, such as a copper-based material. Note that in  FIGS. 1A and 1B  and  FIGS. 2A and 2B , the illustration of the contacts of the electrical connector  10  is omitted. 
     The housing  11  includes a front end wall  12  and a rear end  13 . The front end wall  12  is first inserted when the electrical connector  10  is mated with the mating connector  30 . The rear end  13  is opposed to the front end wall  12  and an electric wire connected to each contact is pulled out from the rear end  13 . Holding holes, not illustrated, for accommodating and holding each contact and the like are provided between the front end wall  12  and the rear end  13 . Note that in each of the electrical connector  10  and the mating connector  30 , a side where the electrical connector  10  and the mating connector  30  are mated is defined as a front side and a side opposite to the front side is defined as a rear side. 
     The housing  11  includes an upper wall  14  and a lower wall  15 . The upper wall  14  extends between the front end wall  12  and the rear end  13 . The lower wall  15  extends between the front end wall  12  and the rear end  13  and is opposed in parallel to the upper wall  14 . A part of the upper wall  14  at the rear end  13  has an inclined surface  16  and a stepped surface  17 . When the upper wall  14  that is next to the inclined surface  16  is defined as a reference surface, the stepped surface  17  is below the reference surface and is in parallel to the reference surface. The housing  11  includes the inclined surface  16 , which prevents water from entering a hood  33  of the mating connector  30  in a state where the electrical connector  10  is mated with the mating connector  30 . This will be described later. 
     The housing  11  also includes a right side wall  18  and a left side wall  19 . The right side wall  18  extends between the front end wall  12  and the rear end  13 . The left side wall  19  extends between the front end wall  12  and the rear end  13  and extends opposite to and in parallel with the right side wall  18 . 
     [Mating Connector  30 ] 
     As shown in  FIGS. 2A and 2B , the mating connector  30  includes a housing  31  and a plurality of contacts  41  held by the housing  31 . The materials of the housing  31  and the contacts  41  are the same as those of the electrical connector  10 . 
     The housing  31  includes a holding wall  32  which is at a rear end of the housing  31  and holds the plurality of contacts  41  in a state with the contacts  41  spaced apart. The housing  31  has a hood  33  which projects forward from the holding wall  32 . The hood  33  has a rectangular tubular shape. A mating opening  38 , which is an opening of the hood  33 , has an end of the hood that is opposed to the holding wall  32 . The hood  33  has a receiving space  39  which receives the electrical connector  10  and is between the holding wall  32  and the mating opening  38 . The electrical connector  10  is inserted from the mating opening  38  into the receiving space  39 . 
     As shown in  FIGS. 2A and 2B , a part of each of the contacts  41  held by the holding wall  32  that is electrically connected to a contact of the electrical connector  10  extends into the receiving space  39  and another part of each of the contacts  41  that is connected to the printed wiring board (not shown) is pulled out backward from the holding wall  32 . As shown in FIGS.  2 A and  2 B, the part of each of the contacts  41  that is pulled out backward is bent by 90 degrees in the middle of the contact. The contacts  41  are disposed in a plurality of columns in a width direction x and are disposed in a plurality of rows in a height direction z. 
     Note that in the electrical connector assembly  1  (the electrical connector  10  and the mating connector  30 ), a side of the electrical connector assembly that faces the printed wiring board to which the contacts  41  are connected is defined as a bottom side and a side of the electrical connector assembly that is opposite to the bottom side is defined as a top side. Accordingly, in  FIGS. 1A and 1B  and  FIGS. 2A and 2B , the upper side of each of the mating connector  30  and the electrical connector  10  corresponds to the top side and the lower side thereof faces bottom side. Even when the orientation of the electrical connector assembly  1  is changed, the definition of the top side and the bottom side remains unchanged. 
     The hood  33  includes an upper wall  34 , a lower wall  35 , and a pair of side walls  36 . The upper wall  34  and the lower wall  35  extend in the width direction x and are opposed to each other at a predetermined interval in the vertical direction. The pair of side walls  36  extends between, in the height direction z, both ends of each of the upper wall  34  and the lower wall  35  in the width direction x. 
     Note that in a usage state, in which the mating connector  30  is mated with the electrical connector  10 , the mating connector  30  according to this embodiment of the present invention is disposed in such a manner that the height direction z matches the vertical direction, i.e., as shown in  FIGS. 2A and 2B , and is connected to the printed wiring board, the illustration of which is omitted. 
     The water stop function obtained by providing the inclined surface  16  and the stepped surface  17  at the rear end of the upper wall  14  of the electrical connector  10  will be described with reference to  FIGS. 3A to 3C . The water stop function works in the state in which the electrical connector  10  and the mating connector  30  are mated together as shown in  FIGS. 2A and 2B .  FIGS. 3A to 3C  illustrate a rear part of the electrical connector  10  and a front end part of the mating connector  30 . 
       FIGS. 3A to 3C  are based on the premise that the water W falls onto a boundary between the rear part of the housing  11  of the electrical connector  10  and the front end part of the housing  31  of the mating connector  30  and the water W adheres to the boundary. In this case, since a gap G between the upper wall  14  of the housing  11  and the upper wall  34  of the mating connector  30  is narrow, the water W adhering to the boundary is likely to flow through the gap G toward the back of the housing  31 , i.e., toward a front side B, due to the capillary action. 
     If the upper wall  14  of the electrical connector  10  forms a uniform flat surface and the gap G is not present, the water W tends to stay at the position. However, as shown in  FIG. 3B , when the water W is in contact with the gap G, a force F 2  toward the front side B of the gap G acts on the water W due to the capillary action, which causes the water to be drawn toward the front side B. 
     However, in the case of the embodiment shown in  FIG. 3A , the inclined surface  16  is provided. With this structure, when the water W adhering to the boundary between the housing  11  and the housing  31  and the water W contacts the inclined surface  16 , a resultant force F 1  of a downward component and a component along the rear side A is generated on the water W, which causes the water W to flow along the inclined surface  16 . The force F 2  is also generated on the water W in the direction of the front side B due to the capillary action in the gap G. However, if the inclination angle θ of the inclined surface  16  is adjusted in such a manner that F 1  is set to be larger than F 2 , the water W can be prevented from being drawn toward the front side B of the gap G. This is the water stop function of the present invention. The force F 2  that causes the water W to enter the gap G can be reduced by increasing the contact angle of the water W that is physically in contact with the gap G. 
     In this embodiment, it is a minimum requirement that the inclination angle θ of the inclined surface  16  exceeds 90° so as to cause the force F 1  including a component in a direction different from that of the force F 2 . The inclination angle θ is 180° (two right angles) at maximum. As the inclination angle θ increases, the contact angle of the water W increases, so that the water stop function for preventing the water W from flowing toward the front side B of the gap G is more likely to be fulfilled. The inclination angle θ is preferably 110° or more, more preferably 120° or more, and even more preferably 130° or more. 
     On the other hand, when the water stop effect due to gravity is taken into consideration, it is preferable to apply a force to the water W in a direction away from the gap G. As the inclination angle θ of the inclined surface  16  increases, the ratio of the space in the height direction z of the electrical connector  10  that is occupied by the inclined surface  16  increases, which inhibits downsizing of the housing  11  in the height direction z. In view of the above, it is necessary to suppress the inclination angle θ and the inclination angle θ is preferably 160° or less, more preferably 150° or less, and even more preferably 140° or less. 
     Most preferably, the inclination angle θ is in a range from 135° to 140°. 
     The present invention is not limited to the above embodiments. The structures illustrated in the above embodiments may be selected or omitted, or may be modified as appropriate to other structures without departing from the principle of the present invention. 
     For example, as shown in  FIG. 4A , when the electrical connector  10  includes a flange-like rear end wall  25  at a rear end of the electrical connector  10  and extends in the outer peripheral direction, it is preferable to have a drainage channel  27  which penetrates the rear end wall  25  so as to cause the water W flowing along the inclined surface  16  to further flow to the outside of the electrical connector. The drainage channel  27  may be continuous in the width direction x, or may be intermittent. It is preferable to have the drainage channel  27  in at least a region corresponding to a region in which the inclined surface  16  is located. 
     Further, the above embodiment illustrates an example of the electrical connector  10  in which the inclined surface  16  is in the entire region in the width direction x. However, the present invention is not limited to this example. For example, as shown in  FIG. 4B , the inclined surface  16  may be only in a part of the region at a central part of the electrical connector  10  in the width direction x. Although not illustrated, the inclined surface  16  may be only in a part of the end of the electrical connector  10  in the width direction x, unlike in  FIG. 4B . For example, the structure of the electrical connector  10  may make it difficult to have the inclined surface  16  in the entire region of the housing  11  in the width direction x. Further, if it is known that a region where water W falls down is limited, it is sufficient to have the inclined surface  16  only in a part of the region of the housing  11  corresponding to this region. 
     As shown in  FIG. 3A , in the electrical connector  10  described above, a starting point S 1  of the inclined surface  16  matches a front end position S 2  of the hood  33  in a mating direction y. However, the present invention is not limited to this example. 
     For example, as shown in  FIG. 5A , even when the starting point S 1  of the inclined surface  16  is shifted to the rear side A relative to the front end position S 2  of the hood  33 , the force F 2  acts on the water W, so that the advantageous effects of the present invention can be achieved. On the contrary, as shown in  FIG. 5B , even when the starting point S 1  of the inclined surface  16  is shifted to the front side B relative to the front end position S 2  of the hood  33 , if the amount of shift is small, the force F 2  acts on the water W, so that the advantageous effects of the present invention can be achieved. Thus, the present invention includes a mode in which the starting point S 1  of the inclined surface  16  is different from the front end position S 2  of the hood  33 . However, according to the present invention, it is most preferable that the starting point S 1  of the inclined surface  16  is in line with the front end position S 2  of the hood  33  in the height direction. 
     Although the above embodiments are based on the premise that the top side of each of the electrical connector  10  and the mating connector  30  is directed upward in the vertical direction, the present invention is not limited to this example. The present invention is also effective when, for example, the mating direction y in which the electrical connector  10  and the mating connector  30  are mated together matches the vertical direction and a certain side of the inclined surface  16  is directed downward in the vertical direction.