Abstract:
An electromagnetic relay has a fixed touch piece having a fixed contact; a movable touch piece, having a movable contact contactably and separably opposed to the fixed contact, and configured to elastically deform, an electromagnet, an intermediate member that rotates based on magnetization and demagnetization of the electromagnet and elastically deforms the movable touch piece, and an energization unit that energizes the movable touch piece to the fixed contact piece side via the intermediate member.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to an electromagnetic relay. 
     2. Related Art 
     As a conventional electromagnetic relay, for example, one is known in which three plate springs are superimposed and integrated by fastening and fixing the one end side at three protrusions while fastening and fixing the other end side with a contact, so as to constitute a spring assembly (movable touch piece) (e.g., see U.S. Pat. No. 7,710,224). 
     However, in the above conventional electromagnetic relay, since the movable touch piece is made up of the three plate springs and those are integrated, in the case of elastically deforming them, it is necessary to act force against elastic force of the three plates. Hence it is necessary to increase driving force generated by a coil assembly (electromagnet) which is used for elastically deforming the movable touch piece. This may cause an increase in the size of the electromagnet or an increase in a current supply amount. 
     SUMMARY 
     One or more embodiments of the present invention smoothly drives a movable touch piece with saved power consumption even when one with a large elastic modulus is used as the movable touch piece. 
     One or more embodiments of the present invention includes: a fixed touch piece having a fixed contact; a movable touch piece, having a movable contact contactably and separably opposed to the fixed contact, and configured to elastically deform; an electromagnet; an intermediate member configured to rotate based on magnetization and demagnetization of the electromagnet and elastically deform the movable touch piece; and an energization unit configured to energize the movable touch piece to the fixed contact piece side via the intermediate member. 
     Here, the intermediate member refers to a member that serves to transmit driving force, which is generated in association with magnetization and demagnetization of the electromagnet, to the movable touch piece. For example, the intermediate member includes a movable iron piece, a card member and the like. 
     With this configuration, since the intermediate member is pressed by the energization unit and the movable touch piece is energized to the fixed touch piece side, it is possible to smoothly elastically deform the movable touch piece even at an initial stage when large suction force cannot be acted on the movable iron piece by energizing the electromagnet. Therefore, even when one with a large elastic modulus is used as the movable touch piece, it is not necessary to increase the size of the electromagnet or increase power consumption. Further, even when impact force acts on the electromagnetic relay, since the intermediate member pressed by the energization unit is energizing the movable touch piece, it is excellent in impact resistance and does not give rise to a defect such as deformation of the movable touch piece. 
     According to one or more embodiments of the present invention, the energization unit is configured so as to no longer perform energization after closing of the contacts. 
     With this configuration, even when the energization force generated by the energization unit is released after closing of the contacts, it is possible to act suction force generated by the electromagnet on the movable touch piece. Further, it is possible to prevent contact pressure from becoming higher than necessary. 
     According to one or more embodiments of the present invention, the energization unit is configured so as to perform energization until the movable touch piece elastically deforms up to a predetermined position before closing of the contacts. 
     With this configuration, since energization force generated by the energization unit does not act on the movable touch piece in the case of demagnetizing the electromagnet, it is possible to smoothly open the contacts by elastic force of the movable touch piece itself. This can result in giving an electromagnetic relay with good operating characteristics. 
     According to one or more embodiments of the present invention, the electromagnet is formed by winding a coil around an iron core via a spool, fastening and fixing one end of a yoke to one end of the iron core while extending the other end of the yoke to the lateral side of the suction surface of the other end of the iron core, the intermediate member include a sucked portion, rotatably supported by the other end of the yoke and contactably and separably opposed to the suction surface of the iron core, and having a pressure receiving portion, and a pressing portion configured to press the movable touch piece, and the energization unit be made up of a hinge spring fixed to the yoke, and have a press piece configured to press the pressure receiving portion of the intermediate member. 
     According to one or more embodiments of the present invention, an electromagnet include a spool having a guard portion on each end of a cylindrical body, an iron core inserted through a central hole of the body of the spool, a coil wound on a periphery of the body of the spool, and a yoke with one end thereof fastened and fixed to one end of the iron core and the other end thereof extending to the lateral side of the suction surface of the other end of the iron core, one guard portion of the spool be a suction-side guard portion formed with a groove portion where the suction surface of the iron core is exposed, the intermediate member include a sucked portion, rotatably supported by the other end of the yoke and contactably and separably opposed to the suction surface of the iron core, and a pressing portion configured to press the movable touch piece, and the energization unit be fitted to the suction-side guard portion of the spool, and have a press piece configured to press the sucked portion of the intermediate member located in the groove portion. 
     With these configurations, just by adding a slight design change to the existing hinge spring and intermediate member, it is possible to easily drive the movable touch piece smoothly, and obtain a configuration excellent in impact resistance. 
     According to one or more embodiments of the present invention, since the intermediate member is pressed by the energization unit to energize the movable touch piece to the contacts-closed side, it is possible to smoothly elastically deform the movable touch piece without increasing the size of the electromagnet or increasing a current supply amount even when the movable touch piece is one having a large elastic modulus. Further, even when impact force acts, since the movable touch piece is energized by the energization unit via the intermediate member, it is excellent in impact resistance and does not give rise to a defect such as deformation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electromagnetic relay according to one or more embodiments of the present invention; 
         FIG. 2  is an exploded perspective view of  FIG. 1 ; 
         FIG. 3  is a perspective view of a base of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of an electromagnet of  FIG. 2 ; 
         FIG. 5A  is an enlarged perspective view of a movable iron piece, a card member and a hinge spring of  FIG. 2 , and  FIG. 5B  is a perspective view showing a state of  FIG. 5A  as seen from a different angle; 
         FIG. 6  is a perspective view of an electromagnet portion of  FIG. 2  in an assembled state as seen from a different angle; 
         FIG. 7  is an enlarged perspective view of a fixed touch piece of  FIG. 2 ; 
         FIG. 8  is an enlarged perspective view of a movable touch piece of  FIG. 2 ; 
         FIG. 9  is a partially ruptured perspective view of a casing shown in  FIG. 1 ; 
         FIG. 10A  is a front view of the electromagnetic relay shown in  FIG. 1 , from which the casing has been removed, with the electromagnet being in a non-magnetized state, and  FIG. 10B  is a partially enlarged view of  FIG. 10A ; 
         FIG. 11A  is a front view showing a state before closing of contacts where the electromagnet has been magnetized from the state of  FIG. 10 , and  FIG. 11B  is a partially enlarged view of  FIG. 11A ; 
         FIG. 12A  is a front view in a state immediately after closing of the contacts where the movable touch piece has been driven from the state of  FIG. 11 , and  FIG. 12B  is a partially enlarged view of  FIG. 12A ; 
         FIG. 13  is a graph showing the relation between a suction force curve and force (driving force) that acts on the movable touch piece; 
         FIG. 14  is a perspective view showing a state of an electromagnet portion and a hinge spring according to one or more embodiments of the present invention as seen from the lower side; 
         FIG. 15  is a perspective view showing an assembled state of each component of  FIG. 14 ; 
         FIG. 16A  is a front view of an electromagnetic relay according to one or more embodiments of the present invention, from which the casing has been removed, with the electromagnet being in a non-magnetized state, and  FIG. 16B  is a partially enlarged view of  FIG. 16A ; 
         FIG. 17A  is a front view showing a state immediately after closing of the contacts where the electromagnet has been magnetized from the state of  FIG. 15 , and  FIG. 17B  is a partially enlarged view of  FIG. 17A ; and 
         FIG. 18A  is a front view in a state after closing of the contacts where the movable touch piece has been driven from the state of  FIG. 16A , and  FIG. 18B  is a partially enlarged view of  FIG. 18A ; 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments according to the present invention will be described in accordance with accompanying drawing. In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention. It is to be noted that in the following description, although terms indicating a specific direction or position (e.g., terms including “upper”, “lower”, “side” or “end”) will be used according to the need, the purpose of using these terms is to facilitate understanding of the invention with reference to the drawings, and the meanings of these terms are not intended to restrict the technical scope of the present invention. Further, the following descriptions are merely illustrative, and are not intended to restrict the present invention, applications thereof or the use thereof. 
       FIG. 1  is a perspective view showing an appearance of an electromagnetic relay according to one or more embodiments of the present invention, and  FIG. 2  is an exploded perspective view thereof. This electromagnetic relay is schematically made up of a base  1 , an electromagnet portion  2 , a contact switch portion  3 , and a casing  4 . 
     As shown in  FIG. 2 , and specifically shown in  FIG. 3 , the base  1  is one formed by molding a synthetic resin material into a plate shape. A central portion on the upper surface of the base  1  is provided with a partition wall  5 , to divide the base  1  into two portions: a first mounting portion  6  to be arranged with the electromagnet portion  2 ; and a second mounting portion  7  to be arranged with the contact switch portion  3 . 
     A central part on the upper surface of the first mounting portion  6  is formed with a lattice-like rib  8  by a plurality of recessed portions having a rectangular shape in a plan view. Further, each side of the first mounting portion  6  is formed with a coil terminal hole  9  having a rectangular shape in a plan view and penetrating between the upper and lower surfaces. 
     The second mounting portion  7  is formed with fixed terminal holes  10  penetrating between the upper and lower surfaces respectively in two places in a width direction along one end surface. Further, a plurality of recessed portions  11  are formed along the fixed terminal holes  10 . The fixed terminal holes  10  and the recessed portions  11  are separated by an auxiliary wall  12  at the center. Further, a fitting recessed portion  13  extending in the width direction is formed adjacent to the plurality of recessed portions  11 . The fitting recessed portion  13  has in the central portion thereof an escape recessed portion  14  extending to the other end side. A central portion on the bottom surface of the escape recessed portion  14  is formed with an aligning hole  15  penetrating to the lower surface. 
     Each side of the partition wall  5  is formed with a guide portion  16  protruding more than this partition wall  5 . Each guide portion  16  is formed with a guide groove  17  extending to the opposed surface in a vertical direction. 
     The electromagnet portion  2  is made up of an electromagnet  18  and a movable iron piece  19  driven by this electromagnet  18 . 
     As shown in  FIG. 4 , the electromagnet  18  is one obtained by winding a coil  22  around an iron core  20  via a spool  21 . 
     The iron core  20  is one formed of a magnetic material into a cylindrical shape. The lower end of the iron core  20  is formed with a guard portion  20   a , and the lower surface thereof is a suction surface  20   b  (cf.  FIG. 10 ). A yoke  23  is fastened and fixed to the upper end of the iron core  20 . 
     The spool  21  is one obtained by molding a synthetic resin material into a substantially cylindrical shape. The coil  22  is wound around a body  24  (cf.  FIG. 10 ) of the spool  21 . Each end of the spool  21  is formed with a guard portion. The upper surface of an upper-end-side guard portion  25  is formed with a groove portion where a horizontal portion of the yoke  23  is to be arranged. The lower surface of a lower-side guard portion  26  is formed with a groove portion where a later-mentioned horizontal portion  19   a  of the movable iron piece  19  is to be arranged. Further, each side of the lower-side guard portion  26  is formed with a coil press-fitting hole  28  where a coil terminal  27  is to be press-fitted. 
     The coil terminal  27  is made of a metallic plate member having conductivity, and the upper end part thereof is formed with a wide portion  29 . Part of the wide portion  29  is cut and raised, to become a winding portion  30  where a leader line of the coil  22  is to be wound. The central part on the side surface of the wide portion  29  is formed with a protrusion  29   a . Further, each side portion of the coil terminal  27  is formed with a protrusion  29   b  protruding to the lateral side in the vicinity of the wide portion  29 . At the time of inserting the coil terminal  27  into the coil press-fitting hole  28  formed in the lower-side guard portion  26  of the spool  21 , these protrusions  29   a ,  29   b  come into a press-fitted state, to align the coil terminal  27  with respect to the spool  21 . 
     The yoke  23  is one formed by bending a plate member made of a magnetic material is bent into a substantially L-shape. A central part of a horizontal portion thereof is formed with a through hole  23   a . The upper end of the iron core  20  is inserted into the through hole  23   a  and fastened. In this fastened state, a vertical portion of the yoke  23  extends to the lower end side along the coil  22  wound around the spool  21 . Each side of the lower end of the vertical portion is a press-fitting portion  31  protruding to the lateral side and to the lower side. The press-fitting portion  31  is press-fitted into the groove  17  formed in the guide portion  16  of the base  1 , to align the yoke  23 , namely the electromagnet  18 , with respect to the base  1 . Further, fastening protrusions  23   b  are formed in two (upper and lower) places on the outer surface of the vertical portion. A hinge spring  32  is fastened and fixed to the yoke  23  through use of these protrusions  23   b.    
     The hinge spring  32  is a platy body having elasticity, and the lower end of which is formed with a substantially C-shaped flexing portion  33 . This flexing portion  33  elastically supports the movable iron piece  19  between itself and the lower end of the yoke  23 . This can make the movable iron piece  19  rotatable around the lower end (specifically a left-side corner in  FIG. 10 ) of the yoke  23 . Further, as shown in  FIG. 5B , a press piece  33   a  is cut and raised in the central portion of the flexing portion  33 . The press piece  33   a  is flexed in an intermediate part, and the leading end portion thereof is a press portion  33   b . The press portion  33   b  comes into press-contact with a later-mentioned pressure receiving surface  19   e  obtained by forming a recessed portion  19   d  in the flexing portion of the movable iron piece  19 . 
     As shown in  FIG. 5 , the movable iron piece  19  is made of a plate member of a magnetic material, and flexed in an intermediate part, to have a substantially L-shape. The horizontal portion  19   a  obtained by the flexing is sucked to the suction surface  20   b  of the iron core  20 . The horizontal portion  19   a  on the base side (a boundary part with the vertical portion  19   b ) is formed with the recessed portion  19   d  having the pressure receiving surface  19   e , with which the press portion  33   b  of the hinge spring  32  is to come into contact. Meanwhile, the vertical portion  19   b  is formed with a rectangular hole  19   c , though which the flexing portion  33  of the hinge spring  32  is to be inserted. Further, the vertical portion  19   b  is formed with through holes (not shown) for integration with a card member  34  in two places in the above part of the rectangular hole  19   c.    
     The movable iron piece  19  is integrated with the card member  34  by insertion molding (or may be integrated not by insertion molding but by thermal fastening or the like). The card member  34  is one formed of a synthetic resin material into the plate shape. The rear surface thereof comes into contact with the vertical portion  19   b  of the movable iron piece  19 , and projected threads  34   a  are formed on peripheral three sides so as to surround this vertical portion  19   b . Further, the rear surface of the card member  34  is formed with a protrusion portion  35  protruding to the rear surface side via a notch formed in the upper part of the vertical portion of the movable iron piece  19 . This protrusion portion  35  comes into contact with the hinge spring  32  fastened and fixed to the yoke  23 , to restrict the range of rotation in this direction. On the other hand, the front surface of the card member  34  is formed with the projected threads  34   a  vertically extending on two rows in the width direction, and the upper end part of each projected thread  34   a  is formed with a pressing portion  36  protruding to the front surface side. The lower end of the card member  34  is formed with a guide piece portion  37  protruding forward and then flexed downward. The guide piece portion  37  is arranged on the second mounting portion  7  side over the partition wall  5  of the base  1 . 
     The contact switch portion  3  is made up of a pair of fixed touch pieces  38  and a movable touch piece  39 . 
     As shown in  FIG. 7 , the fixed touch piece  38  is one formed of a metallic material having conductivity into the plate shape. The fixed touch piece  38  is made up of a press-fitting portion  41  to be press-fitted into the fixed terminal hole  10  formed in the base  1 , a touch piece portion  42  extending upward from the press-fitting portion  41 , and a terminal portion  43  extending to the lower side from the press-fitting portion  41 . One surface of the press-fitting portion  41  is formed with a protrusion portion  41   a  extending in the width direction. The touch piece portion  42  is formed with a slit  44  vertically extending in a central position. Further, a fixed contact  45  is fastened and fixed to the upper end of the touch piece portion  42 . Moreover, the terminal portion  43  is folded from both sides. 
     As shown in  FIG. 8 , the movable touch piece  39  is one formed of a metallic material having conductivity and elasticity into the plate shape. The movable touch piece  39  is made up of a press-fitting portion  46  and a pair of body portions  47  respectively extending from both sides of the press-fitting portion  46  to the upper side. The press-fitting portion  46  is formed with a pair of protrusions  48 , which bulge in a plate thickness direction, at a predetermined interval in the width direction (in  FIG. 7 , only the recessed portion side for forming the protrusions  48  is shown). Each end of the press-fitting portion  46  further extends to the lateral side, and a latching pawl  49  is protruding from the side edge thereof. Further, a central portion at the lower edge of the press-fitting portion  46  is formed with a press-fitting piece  50  further extending downward. Each of the body portions  47  is flexed in the vicinity part of the press-fitting portion  46  and extends, and the upper end of the body portion  47  is formed with a through hole, where a movable contact  51  is fastened and fixed. Further, the upper end of the body portion  47  is formed with an extended portion  52  which is flexed obliquely upward to the fixed touch piece side. 
     As shown in  FIG. 9 , the casing  4  is one obtained by molding a synthetic resin material into the shape of a bottom-open box. The lower-end-side opening of the casing  4  is fitted with the outer side surface of the base  1 , thereby to be fixed to the base  1  and cover each component mounted on the base  1 . Numeral  59  denotes a separation wall to separate a pair of contact switch parts. Numeral  60  denotes a protrusion which is removed after completion of the electromagnetic relay to form a degassing hole communicating between the inside and the outside. However, this protrusion  60  may not be removed and used as it remains in the sealed state. 
     Subsequently, an assembly method for the electromagnetic relay with the above configuration will be described. 
     The coil  22  is wound around the body  24  of the spool  21  and the iron core  20  is inserted through the central hole thereof from the lower side. The coil terminal  27  is press-fitted into the press-fitting hole. In this state, the suction surface  20   b  of the iron core  20  is exposed on the lower surface of the lower-end-side guard portion of the spool  21 . Further, the upper end of the iron core  20  protruding from the upper-end-side guard portion  25  of the spool  21  is inserted into a through hole of the yoke  23 , and fastened and fixed. The yoke  23  is previously fastened and fixed with the hinge spring  32 . Here, the leader line of the coil  22  is wound around the winding portion  30  of the coil terminal  27  and soldered, and thereafter the winding portion  30  is bent along the wound coil  22 . This leads to completion of the electromagnet  18 . 
     The movable iron piece  19  is fitted to the completed electromagnet  18 . In this fitting, the flexing portion  33  of the hinge spring  32  is inserted through the rectangular hole  19   c  of the movable iron piece  19 , and the movable iron piece  19  previously integrated with the card member  34  is elastically supported between the flexing portion  33  and the lower end of the yoke  23 . At this time, the leading end of the press piece  33   a  formed in the flexing portion  33  is brought into contact with the pressure receiving surface  19   e  of the recessed portion  19   d  formed in the movable iron piece  19 . In this state, as shown in  FIG. 6 , elastic force of the press piece  33   a  acts on the movable iron piece  19 , and the movable iron piece  19  is energized such that the horizontal portion  19   a  moves to the suction surface  20   b  side of the iron core  20  around a fulcrum (the lower end of the yoke  23 ). 
     The electromagnet  18  assembled with the movable iron piece  19  in such a manner is mounted on the first mounting portion  6  of the base  1 . That is, the coil terminal  27  is press-fitted into the coil terminal hole  9  of the base  1 , and the press-fitting portion  31  of the yoke  23  is press-fitted into the guide groove  17  formed in the guide portion  16 . 
     Further, the second mounting portion  7  of the base  1  is mounted with the contact switch portion  3 . That is, the terminal portion  43  of the fixed touch piece  38  is press-fitted into the fixed terminal hole  10  from the upper surface side of the base  1 , and this terminal portion  43  is protruded from the lower surface of the base  1 . Moreover, the movable touch piece  39  is press-fitted into the fitting recessed portion  13 . 
     In the contact switch portion  3  mounted on the base  1  in such a manner, the movable touch piece  39  elastically deforms so as to separate the movable contact  51  from the fixed contact  45  by elastic force of its own. Then, the upper side of the body portion  47  of the movable touch piece  39  rotates the movable iron piece  19  integrated with the card member  34  via the pressing portion  36  of this card member  34 . In this state, force acts from the movable iron piece  19  having received energization force of the press piece  33   a  of the hinge spring  32  so as to cancel part of energization force generated by the body portion  47  of the movable touch piece  39 . 
     Finally, the base  1  is covered with the casing  4 , to complete the electromagnetic relay. 
     Next, an operation of the electromagnetic relay with the above configuration will be described. 
     With the electromagnet  18  in the demagnetizing state where a voltage is not applied to the coil  22 , as shown in  FIG. 10 , the movable touch piece  39  is located in a position to separate the movable contact  51  from the fixed contact  45  by the elastic force of its own. Further, the movable iron piece  19  is rotated via the pressing portion  36  of the card member  34 . That is, the movable iron piece  19  rotates clockwise around the lower edge of the yoke  23 , and the horizontal portion  19   a  is held in the state of being separated from the suction surface  20   b  of the iron core  20  of the electromagnet  18 . 
     When a voltage is applied to the coil  22  to magnetize the electromagnet  18 , magnetic force acts from the suction surface  20   b  of the iron core  20  on the horizontal portion  19   a  of the movable iron piece  19 . In this case, although the elastic force is acting from the movable touch piece  39  on the movable iron piece  19  via the pressing portion  36  of the card member  34 , elastic force is acting from the press piece  33   a  of the hinge spring  32  so as to cancel this energization force. 
     Specifically, as shown in a graph of  FIG. 13 , with respect to a curve of suction force which can be acted on the movable iron piece  19  by the electromagnet  18 , force (driving force) required for driving the movable touch piece  39  can be changed at two stages by utilizing the energization force of the press piece  33   a  of the hinge spring  32 . 
     First, until the energization force generated by the press piece  33   a  of the hinge spring  32  is released (initial driving period: cf.  FIG. 10 ), force (driving force) required for elastically deforming the movable touch piece  39  gently changes as shown in a solid straight line (a) in  FIG. 14 . This is because the elastic force generated by the press piece  33   a  of the hinge spring  32  is acting against the elastic force of the movable touch piece  39  so as to cancel this. Accordingly, it is possible to suppress the driving force to be small at the initial stage where the horizontal portion  19   a  of the movable iron piece  19  is apart from the suction surface  20   b  of the iron core  20 , sufficient suction force cannot be acted on the horizontal portion  19   a  of the movable iron piece  19 , and the suction force curve gently changes. 
     Subsequently, when the movable touch piece  39  is driven and the energization force generated by the press piece  33   a  of the hinge spring  32  ceases to act (intermediate driving period: cf.  FIG. 11 ), it becomes necessary to rotate the movable iron piece  19  against the elastic force of the movable touch piece  39 , and the driving force thus increases. However, sufficient suction force can be acted due to the horizontal portion  19   a  of the movable iron piece  19  being close to the suction surface  20   b  of the iron core  20 . Hence it is possible to drive the movable touch piece  39  even when the energization force generated by the press piece  33   a  of the hinge spring  32  is lost. 
     Thereafter, when the movable contact  51  moves onto the fixed contact  45  for closing (final driving period: cf.  FIG. 12 ), driving force for the elastic force of the fixed touch piece  38  in addition to the elastic force of the movable touch piece  39  becomes necessary. In this state, the horizontal portion  19   a  of the movable iron piece  19  comes close to the suction surface  20   b  of the iron core  20 , to allow sufficiently large suction force to be acted. Accordingly, the movable contact  51  is pressed onto the fixed contact  45 , to allow desired contact pressure to be ensured. 
     As thus described, according to the electromagnetic relay in one or more embodiments of the present invention, making the press piece  33   a  of the hinge spring  32  act on the movable iron piece  19  enables suppression of force (driving force) required for driving the movable touch piece  39  at the stage where sufficient suction force cannot be acted in initial magnetization of the electromagnet  18 . This allows smooth switch operations of the contacts. 
     Further, according to the electromagnetic relay in one or more embodiments of the present invention, even when impact force acts due to accidental dropping or the like, a defect such as deformation is not apt to occur since the elastic force from the press piece  33   a  of the hinge spring  32  is acting on the movable touch piece  39  via the card member  34  and the movable iron piece  19 . 
     Other Embodiments 
     It is to be noted that the present invention is not restricted to the embodiments described above, but a variety of modifications can be made. 
     For example, although above, the hinge spring  32  is fixed to the yoke  23  and the press piece  33   a  thereof energizes the movable iron piece  19 , the present invention is not limited thereto. In the following descriptions, constitutional parts corresponding to those above will be provided with the same numerals, and descriptions thereof will be omitted. 
     As shown in  FIGS. 14 and 15 , a hinge spring  61  is made up of a fitting surface portion  62  and an elastic piece portion  63 . 
     The fitting surface portion  62  is formed with a trapezoidal opening  64  in the central portion thereof. A press piece  64   a  is extending obliquely upward from the central portion of one inner edge constituting the opening  64 . This press piece  64   a  can be brought into press-contact with the horizontal portion  19   a  of the movable iron piece  19 , and acts energization force via the movable iron piece  19  and the card member  34  so as to cancel elastic force of the movable touch piece  39 . Further, each side of the fitting surface portion  62  is formed with a rectangular escape hole  65 , through which the coil terminal  27  can be inserted. Moreover, a fitting piece  66  is extending upward at right angle from each end of the fitting surface portion  62 . Each fitting piece  66  is formed with a rectangular fitting hole  67 . 
     The elastic piece portion  63  is formed so as to extend from one side of the outer edge of the fitting surface portion  62 , gradually narrow toward the central portion, and then protrude in parallel. The elastic piece portion  63  is in press-contact with the flexing portion of the movable iron piece  19 , and supports this movable iron piece  19  rotatably around the lower end of the yoke  23  as a fulcrum. 
     Each side surface of a lower-side guard portion (suction-side guard portion)  69  of a spool  68  is formed with a latching protrusion portion  70  where the fitting hole  67  of the fitting piece  66  formed on the fitting surface portion  62  of the hinge spring  61  is to be latched. 
     After the coil  22  has been wound around the iron core  20  via the spool  68  and the coil terminal  27  has been press-fitted and fixed into the lower-side guard portion  69  of the spool  68  to complete an electromagnet  71 , the hinge spring  61  with the above configuration is fitted from the lower side to the lower-side guard portion  69  of the spool  68 . That is, the hinge spring  61  can be easily fitted by inserting the coil terminal  27  through the escape hole  65  of the hinge spring  61  and latching the latching protrusion portion  70  formed on each side surface of the lower-side guard portion  69  of the spool  68  into the fitting hole  67  of each fitting piece  66 . The movable iron piece  19  is then arranged rotatably around the lower end of the yoke  23  as the fulcrum, and the flexing portion  33  is elastically supported by the press piece  64   a  of the hinge spring  61 . According to one or more embodiments of the present invention, each constitutional component is assembled on the base  1 , to complete the electromagnetic relay. 
     In the electromagnetic relay completed as thus described, when the electromagnet  71  not supplying a current to the coil  22  is in a demagnetized state, similar to the above, the movable iron piece  19  rotates clockwise (in  FIG. 16 ) around the fulcrum by elastic force of the movable touch piece  39  which acts via the card member  34 . At this time, the press piece  64   a  of the hinge spring  61 , fitted to the lower-side guard portion  69  of the spool  68 , comes into press-contact with the lower surface of the horizontal portion  19   a  of the movable iron piece  19 . Accordingly, the horizontal portion  19   a  of the movable iron piece  19  is opposed to the suction surface  20   b  of the iron core  20  in the state where part of the elastic force of the movable touch piece  39  is cancelled. 
     Accordingly, similar to the above, in the initial driving period (cf.  FIG. 16 ) when suction force cannot be sufficiently acted by the electromagnet  71  on the movable iron piece  19 , initial driving force can be suppressed by energization force generated by the press piece  64   a  of the hinge spring  61 . 
     Further, in the intermediate driving period (cf.  FIG. 17 ) when the movable touch piece  39  is driven and the energization force generated by the press piece  64   a  of the hinge spring  61  ceases to act, the horizontal portion  19   a  of the movable iron piece  19  comes close to the suction surface  20   b  of the iron core  20  to act sufficient suction force, and thereby allowing rotation of the movable iron piece  19  against elastic force of the movable touch piece  39 . 
     Moreover, in the final driving period (cf.  FIG. 18 ) from the time when the movable contact  51  moves onto the fixed contact  45  for closing, the horizontal portion  19   a  of the movable iron piece  19  comes sufficiently close to the suction surface  20   b  of the iron core  20  to act even larger suction force, thereby allowing exertion of driving force against elastic force of both the movable touch piece  39  and the fixed touch piece  38 . 
     As thus described, according to the electromagnetic relay according to one or more embodiments of the present invention, the hinge spring  61  can be easily fitted to the lower-side guard portion  69  of the spool  68 . Further, it is the press piece  64   a  extending from the inner edge of the opening  64  that energizes the horizontal portion  19   a  of the movable iron piece  19 . For this reason, elastic force to be acted on the movable iron piece  19  can be easily adjusted by just changing an inclined angle of the press piece  64   a.    
     While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.