Abstract:
An electromagnet assembly for an electromagnetic apparatus has a ring member, a coil bobbin having an electrical wire wound a spool of the ring member, and a ring case. The ring member is disposed in an annular groove of the ring case. An opening is formed through the ring case adjacent to its closed end surface. A connector, which is disposed on the ring case and covers the opening, includes a case having a closed shape and a bottom, and a cap closing an open end of the case. Ends of the electrical wire and ends of a lead wire are joined in the connector. A projection portion is formed around a fringe portion of a first end surface of the cap and abuts an open end surface of the case. The cap is secured fixedly to the case after the projection portion is melted.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an electromagnet assembly for use in an electromagnetic apparatus, such as an electromagnetic clutch for use in controlling the transmission of power from an automobile engine to a refrigerant compressor in an automobile air conditioning system. More particularly, it relates to a connector in the electromagnet assembly.  
           [0003]    2. Description of Related Art  
           [0004]    Referring to FIG. 1, an electromagnet assembly  7 , which comprises a ring member  1 , a coil bobbin  3 , and a ring case  4 , is known in the art. Ring member  1  has a toroidal shape having a spool portion, which has an exterior open edge formed by two annular flanges on the spool portion. Coil bobbin  3  has ring member  1  and an electrical wire  2 , which is wound around the spool portion of ring member  1 . Ring case  4  has an annular groove, an open edge of which is in a direction parallel to its axis. Coil bobbin  3  is inserted into the annular groove of ring case  4 . An opening  4   a  is formed through ring case  4  adjacent to its closed end surface. A connector  5  is disposed on ring case  4  adjacent to its closed end surface and covers opening  4   a . A first end  2   a  and a second end  2   b  of electrical wire  2  and a first lead  6   a  and a second lead  6   b  are joined, respectively in connector  5 . Electromagnet assembly  7 , for example, is used in an electromagnetic clutch  9  of a compressor  8  in an automobile air conditioning system, as shown in FIG. 2. Electromagnet assembly  7  engages compressor  8  through a ring-shaped plate  10 , which is affixed to the closed end surface of ring case  4 .  
           [0005]    Referring to FIGS.  3 - 6 , the connecting structure between connector  5  and ring case  4  and the wiring connecting structure in connector  5  is shown. As shown in FIGS. 3 and 4, connector  5  has a case  5   a  having a box shape including a bottom and a cap  5   b , which closes an open end of case  5   a . Case  5   a  is fixed to ring case  4  by a pair of first hooks  10   a  formed on ring-shaped plate  10  which engage a pair of first receiving portions  5   a   1  formed on case  5   a . Cap  5   b  is fixed to case  5   a  by engaging a plurality of second receiving portions  5   a   2  formed at case  5   a  with a plurality of hooks  5   b   1  formed at cap  5   b . A projection portion  5   a   3 , which is formed on case  5   a , is inserted into an opening  4   a . An O-ring  11 , which is disposed in an annular groove formed on case  5   a , surrounds opening  4   a  and abuts the closed end surface of ring case  4 .  
           [0006]    As shown in FIGS.  4 - 6 , first end  2   a  and second end  2   b  of electrical wire  2  are introduced into opening  4   a  through a notched portion  1   a  formed on a first end surface of ring member  1  and are extended into connector  5  through a pair of penetrating holes  5   a   4 , which are formed through projection portion  5   a   3 . A contact  12  having a first electric connection is connected to an end of second lead  6   b , which is inserted into connector  5 . In addition, contact  12  having a second electric connection is connected to an end of first lead  6   a , which is inserted into connector  5 . First end  2   a of electrical wire  2  is supported between a first receiving portion formed at case  5   a of connector  5  and a second receiving portion formed at contact  12 , which is connected to first lead  6   a . Second end  2   b  of electrical wire  2  is supported between a third receiving portion formed at case  5   a  of connector  5  and a fourth receiving portion formed at contact  12 , which is connected to lead  6   b . Thus, first end  2   a  and second end  2   b  of electrical wire  2  are connected to first lead  6   a  and second lead  6   b , respectively.  
           [0007]    Coil bobbin  3  is fixed to ring case  4  by a resin  13  (e.g., an epoxy resin), which is poured into an open end of the annular groove of ring case  4 . O-ring  11 , which is disposed between case  5   a  and the closed end surface of ring case  4 , prevents resin  13  from leaking to the outside of the closed end surface of ring case  4  through the gap between projection portion  5   a   3  of case  5   a  and a surrounding wall of opening  4   a , when resin  13  is poured into ring case  4 .  
           [0008]    In a known electromagnet assembly for use in an electromagnetic apparatus, it is necessary to engage the plurality of hooks  5   b   1  to the plurality of second receiving portions  5   a   2  when cap  5   b  of connector  5  is fixed to case  5   a . Therefore, the manufacturing efficiency of fixing cap  5   b  to case  5   a  is low because this process is done by hand. Further, if the interior of case  5   a  does not fill with resin, water may enter into the interior of case  5   a  through the gap between cap  5   b  and case  5   a , which is adjacent to an engagement portion of hook  5   b   l  and second receiving portion  5   a   2  , and the insulation capabilities of connecting portions of first end  2   a  and second end  2   b  of electrical wire  2  and contact  12  may be reduced. Therefore, it may be necessary to refill the interior of case  5   a  with resin  13 , and the manufacturing efficiency of fixing cap  5   b  to case  5   a  may be reduced.  
         SUMMARY OF THE INVENTION  
         [0009]    An object of the present invention is to provide an electromagnet assembly for use in an electromagnetic apparatus which has a greater manufacturing efficiency in fixing a cap to a case of a connector, when compared with a known electromagnet assembly.  
           [0010]    In an embodiment of the present invention, an electromagnet assembly for an electromagnetic apparatus comprises a ring member, a coil bobbin, a ring case, and a connector. The ring member comprises a tubular spool, e.g., cylindrical spool, with a pair of annular flanges projecting radially from the spool. The coil bobbin comprises an electrical wire. The electrical wire is wound around the spool between the flanges. The ring case comprises an annular groove, which has an open edge. The coil bobbin is disposed in the ring case&#39;s annular groove. An opening is formed through the ring case adjacent to its closed end surface. The connector comprises a case and a cap. The case forms an enclosure, such as a cylinder or a box, having an open end and a bottom. The cap closes the open end of the case. The connector is disposed on the ring case adjacent to its closed end surface and covers the opening. A first end and a second end of the electrical wire, and a first lead wire and a second lead wire from an external electric circuit are connected to the first and the second ends, respectively in the connector. A projection portion is formed around a fringe portion of a first end surface of the cap and abuts an open end surface of the case. The cap is secured fixedly to the case after the projection portion is melted.  
           [0011]    Other objects, features, and advantages will be apparent to persons of ordinary skill in the art from the following description of the invention with reference to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The present invention may be more readily understood with reference to the following drawings.  
         [0013]    [0013]FIG. 1 is a perspective and exploded view of a known electromagnet assembly for use in an electromagnetic apparatus.  
         [0014]    [0014]FIG. 2 is a longitudinal, cross-sectional view of a known compressor for use in an automotive air-conditioning system, which includes an electromagnetic clutch having the known electromagnet assembly.  
         [0015]    [0015]FIG. 3 is a plan view of a closed end surface side of a ring case of the known electromagnet assembly.  
         [0016]    [0016]FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3.  
         [0017]    [0017]FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4.  
         [0018]    [0018]FIG. 6 is a cross-sectional view taken along the line of VI-VI of FIG. 4.  
         [0019]    [0019]FIG. 7 is a plan view of a closed end surface side of a ring case of an electromagnet assembly for use in an electromagnetic apparatus, according to a first embodiment of the present invention.  
         [0020]    [0020]FIG. 8 is a cross-sectional view taken along the line of VIII-VIII of FIG. 7.  
         [0021]    [0021]FIG. 9 is a cross-sectional view of a case and a cap of a connector of the electromagnet assembly before the cap is secured fixedly to the case, according to the first embodiment of the present invention.  
         [0022]    [0022]FIG. 10 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a second embodiment of the present invention.  
         [0023]    [0023]FIG. 11 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a third embodiment of the present invention.  
         [0024]    [0024]FIG. 12 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a fourth embodiment of the present invention.  
         [0025]    [0025]FIG. 13 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a fifth embodiment of the present invention.  
         [0026]    [0026]FIG. 14 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a sixth embodiment of the present invention.  
         [0027]    [0027]FIG. 15 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a seventh embodiment of the present invention.  
         [0028]    [0028]FIG. 16 is a cross-sectional view of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a eighth embodiment of the present invention.  
         [0029]    [0029]FIGS. 17 a  and  17   b  are cross-sectional views of a case and a cap of a connector of an electromagnet assembly before the cap is secured fixedly to the case, according to a ninth embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0030]    Referring to FIGS.  7 - 9 , a first embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus, e.g., an electromagnetic clutch, is shown. In the following explanation and FIGS.  7 - 9 , the same reference numbers are used to represent the same parts of an electromagnet assembly  17  for use in an electromagnetic apparatus as shown FIGS.  1 - 6 . Therefore, further explanation of similar parts is here omitted.  
         [0031]    In electromagnet assembly  17  according to this embodiment, a cap  15   b  of a connector  15  is secured fixedly to an open end surface of a case  15   a  of connector  15  by a high frequency adhesion or an ultrasonic adhesion, or the like. As shown in FIG. 9, a projection portion  15   b   l  is formed around a fringe portion of a first end surface of cap  15   b  and abuts the open end surface of case  15   a . In FIG. 9, cap  15   b  is not secured fixedly on an open end surface of case  15   a . A resin, e.g., an epoxy resin, is not poured into an interior of case  15 . The structure of electromagnet assembly  17  of this embodiment is substantially the same as the known electromagnet assembly  7 , except as described above.  
         [0032]    In electromagnet assembly  17 , cap  15   b  covers the open end surface of case  15   a . Cap  15   b  is secured fixedly to the open end surface of case  15   a , and the abutting portions of cap  15   b  and case  15   a  are melted and fixed together. A process for fixing cap  15   b  to case  15   a  may be easily automated. Consequently, the manufacturing efficiency of fixing cap  15   b  to case  15   a  may be increased. No gap is present between cap  15   b  and case  15   a  after cap  15   b  has been securedly fixedly to the open end surface of case  15   a . Therefore, the entry of water into the interior of case  15   a  may be prevented. As a result, filling the interior of case  15   a  with the resin is no longer necessary. A projection portion  15   b   1  , which is formed around a fringe portion of a first end surface of cap  15   b  and covers the open end surface of case  15   a , has a smaller cross-sectional area and a smaller cubic volume compared to cap  15   b . Therefore, projection portion  15   b   1  is readily and completely melted, and may adhere strongly to the open end surface of case  15   a . As a result, cap  15   b  may be fixed securely to case  15   a .  
         [0033]    Referring to FIG. 10, a second embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, a projection portion  25   b   1  is formed around a fringe portion of a first end surface of a cap  25   b  of a connector  25  and abuts the open end surface of a case  25   a  of connector  25 , and a concave portion  25   a   1 , which engages with projection portion  25   b   1 , is formed on the open end surface of a case  25   a . In FIG. 10, cap  25   b  is not secured fixedly on an open end surface of case  25   a . The structure of this embodiment of the electromagnet assembly is the same as the first embodiment of electromagnet assembly  17 , except as described above. An area of the abutting portions between cap  25   b  and case  25   a  is increased because projection portion  25   b   1  of cap  25   b  engages concave portion  25   a   1  of case  25   a . As a result, a fixing area of cap  25   b  and case  25   a  is increased, and, consequently, cap  25   b  may be more strongly fixed to case  25   a.    
         [0034]    Referring to FIG. 11, a third embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, a first projection portion  35   b   1  is formed around a fringe portion of a first end surface of a cap  35   b  of a connector  35  and covers the open end surface of a case  35   a  of connector  35 , and a plurality of second projection portions  35   b   2 , which determine a position for engaging cap  35   b  with case  35   a , project from a tip of first projection portion  35   b   1  at proper positions. A concave portion  35   a   1 , which faces the plurality of second projection portions  35   b   2  and engages with the plurality of second projection portions  35   b   2 , is formed on the open end surface of a case  35   a . In FIG. 11, cap  35   b  is not secured fixedly on an open end surface of case  35   a . The structure of this embodiment of the electromagnet assembly is substantially the same as the first embodiment of electromagnet assembly  17 , except as described above. Consequently, when preparations for fixing are completed, cap  35   b  may be readily positioned against case  35   a  because the plurality of second projection portions  35   b   2  of cap  35   b  engage concave portion  35   a   l  of case  35   a . As a result, the process for fixing cap  35   b  to case  35   a  may achieve increased productivity.  
         [0035]    Referring to FIG. 12, a fourth embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, a projection portion  45   a   1  is formed on the open end surface of a case  45   a  along its open end surface of case  45   a  of a connector  45 . In FIG. 12, a cap  45   b  is not secured fixedly on an open end surface of case  45   a . The structure of this embodiment of the electromagnet assembly is the same as the first embodiment of electromagnet assembly  17 , except that a projection portion is formed on an open end surface of a case instead of forming a projection portion on a cap. Projection portion  45   a   1 , which is formed on the open end surface of case  45   a , has a smaller cross-sectional area and a smaller cubic volume, as compared to case  45   a . Therefore, projection portion  45   a   1  is readily and completely melted and may adhere strongly to cap  45   b . As a result, cap  45   b  may be more strongly fixed to case  45   a.    
         [0036]    Referring to FIG. 13, a fifth embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, a projection portion  55   a   1  is formed on an open end surface of a case  55   a  along the open end surfac of a connector  55 , and a concave portion  55   b   1 , which engages with projection portion  55   a   1 , is formed around a fringe portion of a first end surface of a cap  55   b . In FIG. 13, cap  55   b  is not secured fixedly on the open end surface of case  55   a . The structure of this embodiment of the electromagnet assembly is substantially the same as the first embodiment of electromagnet assembly  17 , except as described above. An area of the abutting portions of cap  55   b  and of case  55   a  is increased because projection portion  55   a   1  of case  55   a  engages concave portion  55   b   1  of cap  55   b . As a result, a fixing area of cap  55   b  and case  55   a  is increased, and cap  55   b  may be more strongly fixed to case  55   a.    
         [0037]    Referring to FIG. 14, a sixth embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, a first projection portion  65   a   1  is formed on an open end surface of a case  65   a  along the open end surface of a connector  65  and abuts a fringe portion of a first end surface of a cap  65   b , and a plurality of second projection portions  65   a   2 , which determine a position for engaging cap  65   b  with case  65   a , project from a tip of first projection portion  65   a   1  at appropriate positions. A concave portion  65   b   1 , which faces the plurality of second projection portions  65   a   2  and engages with the plurality of second projection portions  65   a   2 , is formed around the fringe portion of cap  65   b . In FIG. 14, cap  65   b  is not secured fixedly on the open end surface of case  65   a . The structure of this embodiment of the electromagnet assembly is substantially the same as electromagnet assembly  17 , except as described above. Consequently, when preparations for fixing are completed, cap  65   b  may be readily positioned against case  65   a  because the plurality of second projection portions  65   a   2  of case  65   a  engage concave portion  65   b   1  of cap  65   b . As a result, the process for fixing cap  65   b  to case  65   a  may achieve increased productivity.  
         [0038]    Referring to FIGS. 15 a  and  15   b , a seventh embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, an open end surface of a case  75   a  of a connector  75  is angled, and a fringe portion of a first end surface of a cap  75   b , which faces the open end surface of case  75   a , is angled to correspond to the angled open end surface of case  75   a . For example, in FIG. 15 a , the angle portion of case  75   a  and cap  75   b  bisect the corner formed by their abutment. Alternatively, in FIG. 15 b , the corner formed by the abutment of case  75   a  and cap  75   b  is primarily comprised of cap  75   b . In FIGS. 15 a  and  15   b , cap  75   b  is not secured fixedly on the open end surface of case  75   a . The structure of this embodiment of the electromagnet assembly is substantially the same as the first embodiment of electromagnet assembly  17 , except that the open end surface of a case  75   a  and the fringe portion of a first end surface of a cap  75   b  are angled. An area of the abutting portion between cap  75   b  and case  75   a  is increased because the angled fringe portion of the first end surface of a cap  75   b  abuts the angled open end surface of case  75   a . As a result, fixing area of cap  75   b  and case  75   a  is increased, and cap  75   b  may be more strongly fixed to case  75   a.    
         [0039]    Referring to FIGS. 16 a  and  16   b , an eighth embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an electromagnet assembly, as shown in FIG. 16 a , a groove  85   a   1  is formed on an interior side wall of a case  85   a  of a connector  85  and is adjacent to an open end surface of case  85   a . A fringe portion of a cap  85   b  of connector  85  is inserted into groove  85   a   1 . As shown in FIG. 16 b , a groove  85   a   2  is formed on an interior side wall of case  85   a  of connector  85  and is adjacent to an open end surface of case  85   a . A projection portion  85   b   1 , which is formed around a side wall of cap  85   b , is inserted into groove  85   a   2  of case  85   a . In FIGS. 16 a  and  16   b , cap  85   b  is not secured fixedly to the open end surface of case  85   a . The structure of this embodiment of the electromagnet assembly is substantially the same as the first embodiment of electromagnet assembly  17 , except that a groove is formed on a case or a projection portion is formed on a cap and a groove is formed on a case. In this embodiment, fringe portion of a cap  85   b  is inserted into groove  85   a   1  formed on the interior side wall of case  85   a  and adjacent to the open end surface of case  85   a . Alternatively, projection portion  85   b   1  formed around the side wall of cap  85   b  is inserted into groove  85   a   2  formed on the interior side wall of case  85   a  and is adjacent to the open end surface of case  85   a . Therefore, an area of the abutting portion between cap  85   b  and case  85   a  is increased, and a fixing area between cap  85   b  and case  85   a  is increased. As a result, cap  85   b  may be more strongly fixed to case  85   a.    
         [0040]    Referring to FIGS. 17 a  and  17   b , a ninth embodiment of the present invention of an electromagnet assembly for use in an electromagnetic apparatus is shown. In this embodiment of an eleotromagnet assembly, as shown in FIG. 17 a , a projection portion  95   a   1  is formed around an interior wall at an open end surface of a case  95   a  of a connector  95 . A hook portion  95   b   1 , which is formed on a first end surface of cap  95   b , extends to engage projection portion  95   a   1  of case  95   a . As shown in FIG. 17 b , a projection portion  95   a   2  is formed around the exterior wall at the open end surface of a case  95   a , and a hook portion  95   b   2  is formed on the first end surface of cap  95   b . Hook portion  95   b   2  extends against projection portion  95   a   2  of case  95   a  and engages projection portion  95   a   2 . In FIGS. 17 a  and  17   b , cap  95   b  is not secured fixedly on the open end surface of case  95   a . The structure of this embodiment of the electromagnet assembly is substantially the same as the first embodiment of electromagnet assembly  17 , except that a projection portion is formed on a case and a hook portion is formed on a cap. In this embodiment, hook portion  95   b   1  or hook portion  95   b   2  of cap  95   b  engages with projection portion  95   a   1  or projection portion  95   a   2  of case  95   a . Therefore, an area of the abutting portion between cap  95   b  and case  95   a  is increased, and a fixing area of cap  95   b  and case  95   a  is increased. As a result, cap  95   b  may be more strongly fixed to case  95   a.    
         [0041]    As described above, in the embodiments of the present invention of an electromagnet assembly for use in an electromagnetic apparatus, a cap is secured fixedly to an open end surface of a case by abutting the cap to the open end surface of the case of a connector. The process for fixing the cap to the case may be readily automated, and the manufacturing efficiency of fixing the cap to the case may be increased. The entry of water into an interior of the case may be prevented because the gap between the cap and the case is no longer formed after the cap is secured fixedly to the case. As a result, it is no longer necessary to fill the interior of the case with a resin, e.g., an epoxy resin. A projection portion, which is formed around a fringe portion of the first end surface of the cap and abuts the open end surface of the case, has a smaller cross-sectional area, and a smaller cubic volume, when compared to the cap. Therefore, the projection portion is readily and completely melted, and may adhere strongly to the open end surface of the case. As a result, the cap may be more strongly fixed to the case.  
         [0042]    Although the present invention has been described in connection with preferred embodiments, the invention is not limited thereto. It will be understood by those skilled in the art that variations and modifications may be made within the scope and spirit of this invention, as defined by the following claims.