Abstract:
An electromagnetic relay includes: a casing formed with an opening; a relay core member adapted for generating an electromagnetic field and inserted into the casing through the opening; an actuating set that is inserted into the relay core member, that is exposed from the casing, and that can be driven by a magnetic attraction force attributed to the electromagnetic field; a terminal set disposed on the casing and adapted to be actuated by the actuating set to thereby act as a switch mechanism; and a housing accommodating the casing, the relay core member, the actuating set and the terminal set.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority of Taiwanese Application No. 097143683, filed on Nov. 12, 2008. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an electromagnetic relay, more particularly to an electromagnetic relay that is easy to assemble accurately and has a relatively higher breakdown voltage value. 
         [0004]    2. Description of the Related Art 
         [0005]    Referring to  FIGS. 1 and 2 , a conventional electromagnetic relay  1  includes a relay core member  11 , a casing  12  for mounting of the relay core member  11 , an actuating set  13 , a terminal set  14 , and a housing  15  for accommodating the relay core member  11 , the casing  12 , the actuating set  13  and the terminal set  14 . The relay core member  11  includes a first mounting frame  112 , a coil  111  wound around the first mounting frame  112 , a yoke component  113  abutting against two adjacent sides of the coil  111 , a magnetic core  114  extending through the coil  111  and connected to the yoke component  113 , a second mounting frame  115  connected to the first mounting frame  112 , and a pair of conductive pins  116  inserted through the second mounting frame  115  and electrically connected to the coil  111 . The actuating set  13  includes a resilient component  131  riveted on the yoke component  113 , a magnetic component  132  pivotable between the resilient component  131  and the first mounting frame  112 , and a drive component  133  connected to the magnetic component  132  and driven thereby. The terminal set  14  includes first, second and third terminals  141 ,  142  and  142  which are disposed on the casing  12 . The third terminal  143  is disposed between the first and second terminals  141 ,  142 , and is connected to and driven by the drive component  133 . 
         [0006]    The conventional electromagnetic relay  1  has the following disadvantages. First, the configuration of connecting the first and second mounting frame  112 ,  115  is easily broken. Second, riveting of the resilient component  131  on the yoke component  113 , and improper positioning of the magnetic component  132  relative to the first mounting frame  112  result in complex and difficult assembly of the relay  1 . Moreover, the casing  12  has an open configuration such that the relay core member  11  of the conventional electromagnetic relay  1  cannot be electromagnetically isolated very well, and is susceptible to interference from the surroundings. Further, assembly accuracy is relatively poor due to the open configuration of the casing  12  such that the conventional electromagnetic relay  1  has a relatively lower breakdown voltage value. 
       SUMMARY OF THE INVENTION 
       [0007]    Therefore, an object of the present invention is to provide an electromagnetic relay that is easy to assemble, that costs relatively less for manufacturing, and that has a relatively higher breakdown voltage value. 
         [0008]    Accordingly, an electromagnetic relay of the present invention comprises a casing, a relay core member, an actuating set, a terminal set, and a housing. 
         [0009]    The casing has a first side formed with an opening and a second side opposite to the first side. The relay core member is adapted for generating an electromagnetic field, is inserted into the casing through the opening, and is formed with a recess having first and second positioning portions which are exposed from the casing. 
         [0010]    The actuating set includes an elongate magnetic component and a resilient component. The elongate magnetic component is inserted into the first positioning portion of the recess in the relay core member, and extends along a direction generally perpendicular to a direction of the electromagnetic field generated by the relay core member. The elongate magnetic component is pivotable between a first position and a second position. The resilient component is inserted into the second positioning portion of the recess in the relay core member and pressing against the magnetic component for providing a resilient force thereto. When the electromagnetic field is generated, the magnetic component is at the second position. When the electromagnetic field is not generated, the magnetic component is biased to the first position. 
         [0011]    The terminal set includes first, second and third terminals which are disposed on the casing. The third terminal is disposed between the first terminal and the second terminal, and is biased to contact the first terminal when the magnetic component is at the first position. The actuating set actuates the third terminal to contact the second terminal when the magnetic component is moved from the first position to the second position. The housing accommodates the casing, the relay core member, the actuating set and the terminal set. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which: 
           [0013]      FIG. 1  is an exploded perspective view illustrating a conventional electromagnetic relay; 
           [0014]      FIG. 2  is a front view of the conventional electromagnetic relay; 
           [0015]      FIG. 3  is an exploded perspective view illustrating the preferred embodiment of the electromagnetic relay of the present invention; 
           [0016]      FIG. 4  is an exploded perspective view illustrating a relay core member of the electromagnetic relay of the preferred embodiment; 
           [0017]      FIG. 5  is a rear view of the preferred embodiment; 
           [0018]      FIG. 6  is a sectional view illustrating the preferred embodiment in a state where a third terminal contacts a first terminal; and 
           [0019]      FIG. 7  is a sectional view illustrating the preferred embodiment in a state where the third terminal contacts a second terminal. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring to  FIG. 3 , an electromagnetic relay of the preferred embodiment includes a casing  2 , a relay core member  3 , an actuating set  4 , a terminal set  5  and a housing  6 . 
         [0021]    Referring to  FIGS. 3 to 6 , the casing  2  has an opening  23  (see  FIG. 5 ), and includes an elongate bottom plate  21 , a block-engaging unit  24  formed with two engaging grooves  241  (only one is shown in  FIG. 3 ) and disposed on an end of the bottom plate  21  proximate to the opening  23 , a terminal-mounting unit  25  disposed on an opposite end of the bottom plate  21  for mounting the terminal set  5 , and a casing body  22  disposed on an intermediate position of the bottom plate  21  and formed with the opening  23 . 
         [0022]    The relay core member  3  is adapted for generating an electromagnetic field, and includes a coil unit  31 , a first mounting frame  32  for mounting the coil unit  31  thereon and disposed within the casing  2 , a second mounting frame  33  connected fixedly to the first mounting frame  32  for sealing the opening  23  in the casing  2  and formed with a recess ( 333 R), an L-shaped limiting component  34 , and a pair of conductive pins  35 . The coil unit  31  includes a coil  311  wound around the first mounting frame  32 , and a magnetic core  312  extending through the coil  311  and the second mounting frame  33  along the direction (X) of the electromagnetic field. The magnetic core  312  includes a neck  313  projecting therefrom. 
         [0023]    Preferably, the first and second mounting frames  32 ,  33  are formed integrally. The first mounting frame  32  includes a connecting end  32 ′ and a non-connecting end  32 ″ opposite to the connecting end  32 ′ and formed with a first through hole  321 . The second mounting frame  33  includes an elongate transverse plate  331  extending along a direction perpendicular to the direction (X) and formed with a second through hole  332 , an engaging block  333  exposed from the casing  2  and formed with the recess ( 333 R), and two barbs  336  disposed on the engaging block  333  and engaging the engaging grooves  241  in the block-engaging unit  24  of the casing  2 . The elongate transverse plate  331  has a first side surface  331 ′ connected fixedly to the connecting end  32 ′ of the first mounting frame  32 , and a second side surface  331 ″ opposite to the first side surface  331 ′. The engaging block  333  extends integrally from the second side surface  331 ″ of the transverse plate  331  along the direction (X) and has a first side surface  333 ′ formed with the recess ( 333 R) and an opposite second side surface  333 ″. 
         [0024]    The recess ( 333 R) is defined by two opposite inner surfaces ( 333 W), and has a first positioning portion  334  and a second positioning portion  335 . The inner surfaces ( 333 W) are formed with two aligned slots ( 333 S) that constitute cooperatively the second positioning portion  335 . 
         [0025]    Moreover, the transverse plate  331  further has a neck-engaging hole  337  formed at a position where the engaging block  333  extends from the transverse plate  331 . The limiting component  34  has a connecting plate part  342  connected to the transverse plate  331 , a limiting plate part  343  perpendicular to the connecting plate part  342 , and a neck  344  projecting from the connecting plate part  342 . The limiting plate part  343  abuts against the non-connecting end  32 ″ of the first mounting frame  32 , and has a third through hole  341  formed through the limiting plate part  343 . The neck  344  fittingly engages the neck-engaging hole  337  in the transverse plate  331 . The magnetic core  312  extends through the first through hole  321  and the second through hole  332 , and the neck  313  of the magnetic core  312  fittingly engages the third through hole  341 , such that removal of the magnetic core  312  from the first mounting frame  32  through the first through hole  321  is prevented. The conductive pins  35  are inserted through the engaging block  333  of the second mounting frame  33 , and are electrically connected to the coil  311 . 
         [0026]    The actuating set  4  includes an elongate magnetic component  41  inserted into the first positioning portion  334  of the recess ( 333 R) in the engaging block  333  and extending along a direction generally perpendicular to the direction (X), a resilient component  42  inserted into the second positioning portion  335  of the recess ( 333 R) in the engaging block  333 , and a drive component  43  extending along the direction (X) for connecting the magnetic component  41  with the terminal set  5 . The magnetic component  41  is pivotable between a first position and a second position. When the electromagnetic field is generated, the magnetic component  41  is at the second position, as shown in  FIG. 7 . When the electromagnetic field is not generated, the magnetic component  41  is biased to the first position, as shown in  FIG. 6 . 
         [0027]    The magnetic component  41  includes an insertion end  411  inserted into the first positioning portion  334  of the recess ( 333 R) in the engaging block  333  and formed with a hole  413  in a surface facing the resilient component  42 , and a traction end  412  connected to the drive component  43 . Preferably, the magnetic component  41  is longer than the transverse plate  331 . The resilient component  42  includes a frame  421  having an inner periphery  420 , a resilient arm  422  connected integrally and inclinedly to the inner periphery  420 , inserted into the hole  413 , and pressing against the magnetic component  41  for providing a resilient force to the magnetic component  41 , a pair of barbs  423  extending respectively from two opposite sides of the frame  421  away from each other and anchored in the slots ( 332 S), respectively, and a limiting plate  424  perpendicularly connected to the frame  421  and exposed from the recess ( 333 R). The limiting plate  424  abuts against the engaging block  333  for positioning the frame  421  of the resilient component  42  within the second positioning portion  335  of the recess ( 333 R) in the engaging block  333 . 
         [0028]    The terminal set  5  includes first, second and third terminals  51 ,  52  and  53  which are disposed on the terminal-mounting unit  25  of the casing  2  such that the terminal set  5  and the opening  23  are disposed respectively at two opposite sides of the casing  2 , wherein the third terminal  53  is disposed between the first terminal  51  and the second terminal  53 , and is connected to the drive component  43  of the actuating set  4 . The third terminal  53  is biased to contact the first terminal  51  when the magnetic component  41  is at the first position, and the drive component  43  of the actuating set  4  actuates the third terminal  53  to contact the second terminal  52  when the magnetic component  41  is moved from the first position to the second position. 
         [0029]    The housing  6  accommodates the casing  2 , the relay core member  3 , the actuating set  4  and the terminal set  5 . 
         [0030]    Referring to  FIG. 7 , when the coil  311  is energized via the conductive pins  35 , the electromagnetic field is generated to attract and move the magnetic component  41  to the second position. At the same time, the traction end  412  of the magnetic component  41  drives the drive component  43  to actuate the third terminal  53  to contact the second terminal  52 . Referring to  FIG. 6 , when the coil  311  is not energized, there is no electromagnetic field generated to attract the magnetic component  41 , and therefore the third terminal  53  is biased to contact the first terminal  51  in a known manner due to a resilient force thereof, and actuates the drive component  43  to push the traction end  412  away from the coil unit  31  to thereby bias the magnetic component  41  to the first position. 
         [0031]    In sum, the electromagnetic relay of the present invention has the following advantages. First, because the magnetic component  41  and the resilient component  42  are inserted respectively into the first and second positioning portions  334 ,  335  of the recess ( 333 R) in the engaging block  333 , it is relatively easy to assemble the electromagnetic relay of the present invention so as to enhance the assembly accuracy. Therefore, an automated manufacturing process can be utilized for the electromagnetic relay of the present invention. Second, the second mounting frame  33  seals the opening  23  in the casing  2  for isolating electromagnetically the coil unit  31  to thereby minimize electromagnetic interference from the surroundings and maintain an effective magnetic attraction for the magnetic component  41 . Third, because the first and second mounting frames  32 ,  33  are formed integrally, and the engaging block  33  extends integrally from the second side surface  331 ″ of the transverse plate  331 , the configuration of the electromagnetic relay of the present invention is relatively strong. Additionally, under the same magnetic attraction of the electromagnetic field, since the magnetic component  41  is longer than the transverse plate  331 , a relatively long moment arm associated with a force applied to the third terminal  53  can be obtained to thereby enhance switching accuracy of the terminal set  5 . 
         [0032]    According to the above-mentioned advantages, it has been verified through experiments that the electromagnetic relay of the present invention has a breakdown voltage value much higher than that of a conventional electromagnetic relay. Therefore, the service life of the electromagnetic relay of the present invention is relatively longer. 
         [0033]    While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.