Patent Publication Number: US-6659786-B2

Title: Electrical connector

Description:
FIELD OF THE INVENTION 
     The present invention relates to an electrical connector system having movably mounted contacts to accommodate misalignment between male and female connector parts. 
     DESCRIPTION OF THE PRIOR ART 
     Fuel cells are electrochemical systems, which convert the chemical energy from oxidation processes directly into electrical energy. This electrical energy has to be forwarded to the various devices via the power supply unit. In mobile applications in particular, the connection between fuel cell and power supply unit must occupy a minimum amount of space. In applications requiring a plurality of connectors, the male connector parts are generally mounted on the power supply unit and the female connector parts on the fuel cell. The respective manufacturing tolerances may however create positional variational or misalignment between male connector parts and female connector parts, which lead to damage to the connector. At the same time, due to the extremely harsh environmental conditions, the connector assemblies are required to withstand vibration, corrosion, and heat while maintaining current carrying capacity. In addition, the connection has to be capable of being frequently released and reliably reconnected with low insertion force. 
     Since the output voltages supplied by the fuel cell are direct current voltages of up to approx. 800 volts, the contact socket should be automatically closed in an unmated condition to avoid unintentionally inserted items. 
     An object of the present invention is therefore to provide an electrical connector which compensates any offset or misalignment between female connector part and male connector part resulting from manufacturing tolerances without damage thereto during mating. A further object with such connectors is to protect the contact socket from unintentional contact when the contact pin is not inserted therein. 
     SUMMARY OF THE INVENTION 
     The invention provides an electrical connector having a male connector part having a contact pin and a first base member, a female connector part having a contact socket and a second base member. The contact pin is insertable into the contact socket in order to effect electrical connection between the male connector part and the female connector part. At least one of the contact pin or the contact socket are mounted movably in the respective base member and precentred in the respective base member by means of a spring via a centring bevel, which is provided on the respective base member. 
     According to an embodiment of the invention, the contact pin has an insertion bevel at the end. The centring process during insertion of the contact pin into the contact socket is thereby simplified. 
     If an insertion cone is provided at the end of the contact socket, the centring process during insertion may be further simplified. 
     A particularly flexible, economic option for achieving movable mounting consists in mounting the contact pin and/or the contact socket in the respective base member with adequate play. 
     In order to achieve a central starting position for the movably mounted contact pin and/or contact socket, the contact pin and/or the contact socket may be precentred in the respective base member by means of a spring or a centring bevel, which is provided on the respective base member. Particularly suitable for this purpose is an angle of approx. 10° between the centring bevel and the cross-sectional plane of the connector. 
     According to another embodiment, the first base member and/or the second base member comprise(s) retaining projections on an inner side which interact with corresponding projections on the contact pin and/or the contact socket to prevent axial displacement of the contact pin and/or the contact socket. It is thereby ensured that the contact pin and/or the contact socket has/have sufficient mechanical stability for fitting together and release of the electrical connection. 
     In another embodiment of the invention, the connector assembly, it may be ensured that the contact socket is secured in the open state against undesired contact and the contact pin may easily open this securing means upon closure of the electrical connection. To this end, the contact pin comprises an insertion bevel, which exerts uniform, radially outwardly directed mechanical pressure on the closing element and thereby releases it. 
     According to another embodiment, the closing elements are held by a spring in the closed state when the contact pin is not inserted. It may thereby be ensured that the contact socket of the open electrical connector is always automatically protected against unintentional contact. 
     Particularly precise adjustability of the required spring forces is achieved by using a shaped wire spring. On the other hand, the use of a worm spring is particularly simple with regard to construction, since in this case only a simply produced annular receptacle needs to provided on the outside of the contact insulation to fix the spring in place. 
     Additional security against the penetration of very thin wires (diameter 1 mm, see IEC 529) is provided by an embodiment in which the female part of the electrical connector comprises a further closing element, which closes the contact socket and may be displaced in the axial direction once the contact pin has released the closing elements. 
     In order to bring this closing element also automatically into its securing position, as soon as a contact pin is no longer inserted, this further closing element may likewise be held by means of a spring. 
     According to another embodiment, the contact pin comprises a contact member and an insertion cap separate therefrom. In this way, it may be ensured that the insertion bevel, which is under particular mechanical stress during insertion of the contact pin, may be made of a particularly suitable material, which exhibits relatively poor electrical characteristics, however. In this embodiment, the actual contact member which produces the electrical connection may be made of the material best fulfilling these requirements. 
     By providing the contact socket with a contact tube and a separate locating bush, the contact pin is additionally centred by the locating bush and relatively large transverse forces are not transmitted to the contact tube but rather are absorbed by the locating bush. 
     Depending on the requirements made of the electrical connector, the respective features involved in movable mounting of contact pin and/or contact socket and in securing of the contact socket against unintentional contact may be used alone or in combination. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail below with reference to the preferred embodiments illustrated in the attached drawings, in which: 
     FIG. 1 shows a section through a male connector part of the electrical connector of a first embodiment; 
     FIG. 2 is a view of the male connector part of the electrical connector of the first embodiment; 
     FIG. 3 is a further view of the male connector part of the electrical connector of the first embodiment; 
     FIG. 4 is an exploded view of the male connector part of the electrical connector of the first embodiment; 
     FIG. 5 shows a section through a female connector part according to a first embodiment; 
     FIG. 6 is a view of the female connector part according to the first embodiment; 
     FIG. 7 shows a further section through the female connector part according to the first embodiment; 
     FIG. 8 shows a further section through the female connector part according to the first embodiment; 
     FIG. 9 is an exploded view of the female connector part according to the first embodiment; 
     FIG. 10 is a view of the female connector part according to the first embodiment; 
     FIG. 11 is an exploded view of the female connector part according to the first embodiment; 
     FIG. 12 is a view of the entire connector of the invention according to the first embodiment; 
     FIG. 13 shows a section through the entire connector of the invention according to the first embodiment; 
     FIG. 14 shows a further section through the entire connector of the invention according to the first embodiment; 
     FIG. 15 is an exploded view of the entire connector of the invention according to the first embodiment; 
     FIG. 16 is a partially sectional view of the power supply unit with a female connector part according to a second embodiment; 
     FIG. 17 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 18 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 19 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 20 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 21 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 22 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 23 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 24 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 25 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 26 is a further partially sectional view of the power supply unit with the female connector part according to the second embodiment; 
     FIG. 27 is a partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 28 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 29 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 30 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 31 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 32 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 33 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 34 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 35 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 36 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 37 is a further partially sectional view of the power supply unit with the female connector part according to the invention and the associated male connector part according to the invention; 
     FIG. 38 shows a section through a female connector part according to a third preferred embodiment; 
     FIG. 39 shows a further section through a female connector part according to the third embodiment; 
     FIG. 40 is a view of the female connector part according to the third embodiment; 
     FIG. 41 is an exploded view of the female connector part according to the third embodiment; 
     FIG. 42 shows a section through a female connector part according to a fourth embodiment; 
     FIG. 43 shows a further section through the female connector part according to the fourth embodiment; 
     FIG. 44 is a view of the female connector part according to the fourth embodiment; 
     FIG. 45 shows an exploded view of the female connector part according to the fourth embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     If electrical contact is to be established between a fuel cell and a power supply unit (Power Distribution Unit, PDU), a male connector part  102  according to the invention and shown in FIGS. 1 to  4  may serve to compensate any possible offset or misalignment between a female connector part  104  and the male connector part  102  due to manufacturing tolerances. According to the invention, a contact pin  106  is mounted in a base member  110  with sufficient play  108  for this purpose. A pressure spring  112  presses the contact pin  106  against a 10° bevel  114 , which is provided on guide bushing  116  connected with the base member  110 . The spring force of the pressure spring  112  aligns the contact pin  106  in a centred manner with the assistance of the centring bevel  114 . The pressure spring  112  rests on the washer  118 , which is firmly connected with the contact pin  106 . Mechanical stability relative to axial load in both directions is achieved by interaction of the washer  118  with a corresponding retaining device on the pressure spring  112  and by the centring bevel  114  providing a limit stop for the contact pin  106 . 
     The sealing ring  122 , which is pushed over the base member, seals the electrical contact relative to the environment when the connector is fitted together. The contact pin  106  has insertion bevels  124  at its end. These simplify the centring process upon insertion of the contact pin  106  into the contact socket  128 . The end area with the insertion bevel  124  takes the form of a push-on cap  126 . It may thereby be ensured that different, particularly suitable materials may be used in each case for electrical contacting and for the insertion bevel  124 . 
     FIGS. 5 to  11  show the associated female connector part  104  in a first embodiment. The female connector part  104  comprises a contact socket  128 , into which the contact pin  106  may be inserted for electrical connection with the male connector part  102 . 
     As best shown in section B—B of FIG.  5  and section A—A of FIG. 7, the contact socket  128  has a locating bushing  130  and a contact tube  132 , which are embedded in contact insulator  134 . The contact insulator  134  serves as a preliminary alignment feature for the contact pin  106  and is provided for this purpose with an insertion cone  147 . When the contact pin  106  has been pushed through the contact tube  132  on insertion, it is additionally centred in the locating bushing  130 . Relatively large transverse forces are thereby not transmitted to the contact socket  132  but rather are absorbed by the contact insulator  134  and the locating bushing  130 . 
     The base member  136 , which surrounds the contact socket  128  has shielding  138  formed by the housing of the fuel cell and has an inner coating  139  machined for contact with the sealing ring  122 . An insulating disk  140  connects the shielding  138  with the contact insulator  134 . 
     Closing elements  142 , which are provided on the contact insulator  134 , are compressed by a pretensioned closing spring  144 , such that they close the insertion opening  146  when no contact pin  106  is inserted in the female connector part  104 . The special three-dimensional form of the shaped wire spring  144  provides the necessary large spring travel and the necessary closing force. In principle, two separate closing springs  144  may also be used. 
     FIGS. 12 to  15  show the connector  100  according to the invention after mating. During the insertion process, mechanical pressure directed uniformly in the radially outwards direction is exerted on the closing elements  142  by the insertion bevel  124  on the contact pin  106  to open the closing elements  142 . The contact pin  106  may then be fully inserted. Electrical connection is effected via the contact member  107  and the contact tube  132 . The majority of the mechanical forces arising during centring of the movably mounted contact pin  106  is absorbed by the locating bushing  130  and the contact insulator  134 . In this way, damage to the more sensitive contact tube  132  may be prevented. 
     FIGS. 16 to  26  show different, partially sectional views of a power supply unit  148  with the male connector part  102  of a connector  100  according to a second embodiment. As is clear for example from FIG. 16, the contact pin  106  is mounted movably in a guide bushing  116 , as in the exemplary embodiment shown in FIG. 1. A pressure spring  112  ensures appropriate precentring by means of the centring bevel  114 . In contrast to the embodiment shown in FIG. 1, the contact pin  106 , as may be seen from FIG. 16 for example, comprises a substantially tubular securing pin receptacle  150 , into which a securing pin  152 , provided on the female connector part  104 , may be inserted. The contact pin additionally has a mechanically stable cap  126  with insertion bevels  124 . 
     FIGS. 27 to  37  show the power supply unit  148  of FIG. 16 with inserted female connector part  104 , which is coupled with the fuel cell  149 . As in the embodiment illustrated in FIG. 5, the contact socket  128  has a locating bushing  130  and a contact tube  132 . In addition, a securing pin  152  is provided on the female connector part  104 , which may be inserted into the securing pin receptacle  150  of the male connector part  102 . As is clear from FIG. 28, two connector assemblies  100  are necessary for making contact between power supply unit  148  and fuel cell  149 . Since both the position of the two male connector parts  102  on the power supply unit  148  and the position of the two female connector parts  104  on the fuel cell  149  are fixed during their respective manufacture, it is extremely important for any mismatch caused by manufacture between the real and ideal axes of the connector to be capable of compensation by the movable mounting of the contact pin  106 . 
     FIGS. 38 to  41  show a third embodiment of the female connector part  104  according to the invention. In contrast to the embodiment shown in FIGS. 5 to  11 , a resilient ring is used as a closing spring  144  for the closing elements  142  in the case of the female connector part  104  shown in FIGS. 38 to  41 . This resilient ring  144  takes the form of a worm spring. Worm springs are tension springs which are connected at the ends to produce a ring and as a rule are made from spring steel helices. Due to the tensile force of the closing spring  144 , the closing elements  142  are pressed radially inwards and close the insertion opening  146 , if no contact pin  106  is inserted therein. 
     A further embodiment of the female connector part  104  is shown in FIGS. 42 to  45 . In this variant, a substantially cylindrical further closing element  145  closes the insertion opening  146 . When the contact is closed, the further closing element  145  is pressed against the pressure spring  154  and is located in position  143 A. If no contact pin  106  is inserted, the further closing element  145  is pressed by the pressure spring  154  into the position  143 B. In this way, the closing element  142  forms a limit stop for the further closing element  145 . In the present embodiment, this closing element  142  is itself resilient and requires no additional closing spring in order to be compressed. The contact pin  106  is in a position, due to its insertion bevel  124 , to open the closing element  142  by uniform pressure directed radially outwards. Due to a lack of insertion bevels on the further closing element  145 , the latter is trapped inside the contact. 
     Although the exemplary embodiments in the drawings show the contact pin and contact socket with circular cross sections, the present invention may also be applied to contact pins and contact sockets of rectangular cross section. 
     The connector is shown in the embodiments illustrated as a shielded connector. The construction according to the invention may also be applied to an unshielded connector, however. In the case of the unshielded variant, the number of necessary components could even be reduced. 
     An advantage of the connector according to the invention consists in the fact that any offset of the axes of contact pin and contact socket upon fitting together of the two parts is compensated by mounting the contact pin and/or contact socket movably in the respective base member. In this way, damage to the contact socket may be prevented.