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 auxiliary member configured to energize the movable touch piece to the fixed contact piece side, an electromagnet, and an intermediate member configured to be operated by magnetization of the electromagnet and elastically deform the movable touch piece.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to an electromagnetic relay. 
         [0003]    2. Related Art 
         [0004]    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). 
         [0005]    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 result in having to increase the size of the electromagnet or increase a current supply amount. 
       SUMMARY 
       [0006]    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. 
         [0007]    An electromagnetic relay according to 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 auxiliary member configured to energize the movable touch piece to the fixed contact piece side; an electromagnet; and an intermediate member configured to be operated by magnetization of the electromagnet and elastically deform the movable touch piece. 
         [0008]    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. 
         [0009]    With the above configuration, since the movable touch piece is energized to the fixed touch piece side by the auxiliary member, 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 intermediate member 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 auxiliary member 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. 
         [0010]    According to one or more embodiments of the present invention, the auxiliary member energizes the movable touch piece from the surface on the opposite side to the fixed touch piece. 
         [0011]    According to one or more embodiments of the present invention, the auxiliary member is configured so as to energize the movable touch piece to the fixed touch piece side up to a predetermined position before closing of the contacts. 
         [0012]    With this configuration, since energization force generated by the auxiliary member 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. 
         [0013]    According to one or more embodiments of the present invention, the auxiliary member is configured so as to no longer energize the movable touch piece after closing of the contacts. 
         [0014]    With this configuration, even when the energization force generated by the auxiliary member 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. 
         [0015]    According to one or more embodiments of the present invention, the auxiliary member comes into surface-contact from a terminal portion of the movable touch piece to a vicinity of the movable contact. 
         [0016]    With this configuration, namely a configuration where the movable touch piece and the auxiliary member are brought into surface-contact with each other, it is possible to increase a sectional area, so as to increase a current capacity. In this case, since the auxiliary member is not fixed to the movable touch piece, it just follows elastic deformation of the movable touch piece. Therefore, even when the movable touch piece is repeatedly driven, stress is not concentrated as in the case of it being fixed. That is, the repetition elasticity life of the movable touch piece can be set to a desired value. 
         [0017]    According to one or more embodiments of the present invention, due to provision of the auxiliary member for energizing 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 auxiliary member, it is excellent in impact resistance and does not give rise to a defect such as deformation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view of an electromagnetic relay according to one or more embodiments of the present invention; 
           [0019]      FIG. 2  is an exploded perspective view of  FIG. 1 ; 
           [0020]      FIG. 3  is a perspective view of a base of  FIG. 2 ; 
           [0021]      FIG. 4  is an exploded perspective view of an electromagnet of  FIG. 2 ; 
           [0022]      FIG. 5A  is an enlarged perspective view of a movable iron piece and a card member of  FIG. 2 , and  FIG. 5B  is a perspective view showing a state of  FIG. 5A  as seen from a different angle; 
           [0023]      FIG. 6  is an enlarged perspective view of a fixed touch piece of  FIG. 2 ; 
           [0024]      FIG. 7  is an enlarged perspective view of a movable touch piece and an auxiliary member of  FIG. 2 ; 
           [0025]      FIG. 8  is a front sectional view of the electromagnetic relay shown in  FIG. 1  in a state where a casing and a contact switch portion have been removed; 
           [0026]      FIG. 9  is a partially ruptured perspective view of the casing shown in  FIG. 1 ; 
           [0027]      FIG. 10  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; 
           [0028]      FIG. 11  is a front view showing a state immediately after closing of contacts where the electromagnet has been magnetized from the state of  FIG. 10 ; 
           [0029]      FIG. 12  is a front view in a state where a fixed contact is pressed onto by a movable contact from the state of  FIG. 11 ; 
           [0030]      FIG. 13  is a graph showing the relation between a suction force curve and force (driving force) that acts on the movable touch piece; 
           [0031]      FIG. 14  is a front view of an electromagnetic relay according to one or more embodiments of the present invention, showing a state immediately after closing of the contacts where the electromagnet has been magnetized from the state of  FIG. 10 ; 
           [0032]      FIG. 15  is a front view in a state where the fixed contact has been pressed onto by the movable contact from the state of  FIG. 14 ; 
           [0033]      FIG. 16  is a perspective view of a movable touch piece and an auxiliary member according to one or more embodiments of the present invention; 
           [0034]      FIG. 17  is a front view of an electromagnetic relay provided with the movable touch piece and the auxiliary member shown in  FIG. 16 , from which the casing has been removed, with the electromagnet being in a non-magnetized state; 
           [0035]      FIG. 18  is a front view showing a state before closing of the contacts where the electromagnet has been magnetized from the state of  FIG. 17 ; 
           [0036]      FIG. 19  is a front view showing a state immediately after closing of the contacts where the movable touch piece has been driven from the state of  FIG. 18 ; 
           [0037]      FIG. 20  is a front view in a state where the fixed contact has been pressed onto by the movable contact from the state of  FIG. 19 ; and 
           [0038]      FIG. 21A  is a perspective view showing a state before bending of the movable touch piece and the auxiliary member which are integrally formed according to one or more embodiments of the present invention, and  FIG. 21B  is a perspective view showing a state after the bending. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    Hereinafter, embodiments of 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. 
         [0040]      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 . 
         [0041]    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 . 
         [0042]    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. 
         [0043]    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. 
         [0044]    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. 
         [0045]    The electromagnet portion  2  is made up of an electromagnet  18  and a movable iron piece  19  driven by this electromagnet  18 . 
         [0046]    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 . 
         [0047]    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. A yoke  23  is fastened and fixed to the upper end of the iron core  20 . 
         [0048]    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. 8 ) 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. Each side of a lower-side guard portion  26  is formed with a coil press-fitting hole  28  where a coil terminal  27  is to be press-fitted. 
         [0049]    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 . 
         [0050]    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, the horizontal 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 a vertical portion of the yoke  23  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 guide 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.    
         [0051]    A substantially C-shaped flexing portion  33  is formed on the lower end side of the hinge spring  32 . 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. 8 ) of the yoke  23 . 
         [0052]    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. A horizontal portion  19   a  obtained by the flexing is sucked to the suction surface of the iron core  20 . A 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.    
         [0053]    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 . 
         [0054]    The contact switch portion  3  is made up of a fixed touch piece  38 , a movable touch piece  39  and an auxiliary member  40 . 
         [0055]    As shown in  FIG. 6 , 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. 
         [0056]    As shown in  FIG. 7 , 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. 
         [0057]    As shown in  FIG. 7 , the auxiliary member  40  is one formed of a metallic material having conductivity and elasticity into the plate shape, as is the above movable touch piece  39 . The auxiliary member  40  is made up of a press-fitting portion  53  and energizing portions  54 . In the press-fitting portion  53 , in positions corresponding to the pair of protrusions  48  formed in the movable touch piece  39 , recessed portions to be superimposed thereon are respectively formed, and protrusions  55  are thereby formed respectively (in  FIG. 7 , only the recessed portion side for forming the protrusion  55  is shown.). Moreover, the press-fitting portion  53  is further extending from each side to the lateral side. A central portion at the lower edge of the press-fitting portion  53  is formed with a first notch  56 , and each side thereof is formed with a second notch  57  having a smaller cutting depth. The first notch  56  corresponds to the position of the press-fitting piece  50  of the movable touch piece  39 . The press-fitting portion  53  then comes into surface-contact with the press-fitting portion  46  of the movable touch piece  39 . The energizing portion  54  protrudes from each side portion at the upper edge of the press-fitting portion  53 , and is then inclined to the movable touch piece side. The upper end part of the energizing portion  54  is formed with a pressing protrusion portion  58  to press the movable touch piece  39 . The pressing protrusion portion  58  is made up of a projected thread extending in a width direction of the energizing portion  54 . 
         [0058]    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. 
         [0059]    Subsequently, an assembly method for the electromagnetic relay with the above configuration will be described. 
         [0060]    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 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 . In the completed electromagnet  18 , the movable iron piece  19  is elastically supported between the flexing portion  33  of the hinge spring  32  and the lower end of the yoke  23 . The movable iron piece  19  is previously integrated with the card member  34 . 
         [0061]    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 . 
         [0062]    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 . Further, the movable touch piece  39  and the auxiliary member  40  are superimposed on each other in the press-fitting portions  46 ,  53 , and press-fitted into the fitting recessed portion  13 . At this time, since the protrusion  48  on the movable touch piece  39  side is engaged with the recessed portion for forming the protrusion  55  on the auxiliary member  40  side in the press-fitting portions, they can be smoothly press-fitted into the fitting recessed portion  13  without displacement. The engaged part then exerts a press-contact function to come into press-contact with the inner wall of the fitting recessed portion  13 . 
         [0063]    In the contact switch portion  3  mounted on the base  1  in such a manner, the movable touch piece  39  separates 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, energization force generated by the energizing portion  54  of the auxiliary member  40  acts so as to cancel part of energization force generated by the body portion  47  of the movable touch piece  39 . 
         [0064]    Finally, the base  1  is covered with the casing  4 , to complete the electromagnetic relay. 
         [0065]    Next, an operation of the electromagnetic relay with the above configuration will be described. 
         [0066]    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  (cf.  FIG. 8 ), and the horizontal portion  19   a  is held in the state of being separated from the suction surface of the iron core  20  of the electromagnet  18 . 
         [0067]    When a voltage is applied to the coil  22  to magnetize the electromagnet  18 , magnetic force acts from the suction surface of the iron core  20  on the horizontal portion  19   a  of the movable iron piece  19 . 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 , the energization force is acting from the auxiliary member  40  on the movable touch piece  39  so as to cancel this elastic force. Accordingly, in initial magnetization of the electromagnet  18 , even in a state where the horizontal portion  19   a  of the movable iron piece  19  is most apart from the suction surface of the iron core  20  and the suction force cannot be sufficiently acted, the movable iron piece  19  can be rotated against the elastic force of the movable touch piece  39  as shown in  FIGS. 10 to 12 . 
         [0068]    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 providing the auxiliary member  40 . 
         [0069]    First, until the energization force generated by the auxiliary member  40  is released (initial driving period: in  FIG. 10  before  FIG. 11 ), force (driving force) required for elastically deforming the movable touch piece  39  gently changes as shown in a solid straight line (a) in  FIG. 13 . This is because the elastic force generated by the auxiliary member  40  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 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. With the auxiliary member  40  being not fixed to the movable touch piece  39 , the auxiliary member  40  makes the movable touch piece  39  change a sliding-contact position at the initial driving period. This can prevent occurrence of early damage and the like due to an increase in elastic force or stress concentration on a fixed place as in the case of those being fixed to each other. 
         [0070]    Subsequently, when the movable touch piece  39  is driven and the energization force generated by the auxiliary member  40  ceases to act (intermediate driving period:  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 of the iron core  20 . Hence it is possible to drive the movable touch piece  39  even when the energization force generated by the auxiliary member  40  is lost. 
         [0071]    Thereafter, when the movable contact  51  moves onto the fixed contact  45  for closing, 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 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 (final driving period: from  FIG. 11  till  FIG. 12 ). 
         [0072]    As thus described, according to the electromagnetic relay described above, providing the auxiliary member  40  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. 
         [0073]    Further, according to the electromagnetic relay described above, even when impact force acts due to accidental dropping or the like, a defect such as deformation is not apt to occur since the auxiliary member  40  is in press-contact with the movable touch piece  39 . 
         [0074]    It is to be noted that the present invention is not restricted to the configuration described above, but a variety of modifications can be made. 
         [0075]    For example, although according to one or more of the above embodiments, the energization force generated by the auxiliary member  40  ceases to act on the movable touch piece  39  before the movable contact  51  moves onto the fixed contact  45  for closing as shown in  FIGS. 10 to 12 , according to one or more embodiments of the present invention, the auxiliary member  40  may be constantly in press-contact with the movable touch piece  39  as shown in  FIGS. 14 and 15 . 
         [0076]    That is, in the demagnetized state of the electromagnet  18  shown in  FIG. 10 , a voltage is applied to the coil  22  to magnetize the electromagnet  18 , and as shown in  FIG. 14 , the movable touch piece  39  is elastically deformed to move the movable contact  51  onto the fixed contact  45  for closing. During this operation, the auxiliary member  40  energizes the movable touch piece  39 , to support elastic deformation of the movable touch piece  39 . Then as shown in  FIG. 15 , a configuration is formed such that at the stage of the movable contact  51  pressing onto the fixed contact  45  after closing of the contacts, the state of pressing by the auxiliary member  40  is released and the movable touch piece  39  is no longer pressed. 
         [0077]    Further, although the one surface (the surface on the opposite side to the fixed touch piece  38 ) of the movable touch piece  39  is pressed by the auxiliary member  40  in one or more of the above embodiments, a configuration may be formed such that it is pulled from the fixed touch piece  38  side as shown in  FIG. 16 . It is to be noted that in the following description, the same configurations as those of the movable touch piece  39  and the auxiliary member  40  shown in  FIG. 7  will be provided with the corresponding numerals, and descriptions thereof will be omitted. 
         [0078]    That is, a guide hole  61  is formed in a part below the movable contact  51  in the body portion  47  of a movable touch piece  60 . The guide hole  61  is made up of a slit portion  61   a  along a central line of the body portion  47  and a wide portion  61   b  continued from the lower end of the slit portion  61   a . On the other hand, a guide protrusion portion  63  guided from the central portion at the upper end of each energizing portion  54  to the guide hole  61  protrudes in an auxiliary member  62 . The guide protrusion portion  63  is made up of a connection portion  63   a  having a smaller width than the slit portion  61   a , and a latching portion  63   b  provided at the leading end of the connection portion  63   a . The latching portion  63   b  is insertable into the wide portion  61   b , and formed wider than the slit portion  61   a.    
         [0079]    The auxiliary member  62  is arranged such that the press-fitting portions  46 ,  53  come into surface-contact with each other on the fixed touch piece  38  side with respect to the movable touch piece  60 . Then, the guide protrusion portion  63  of the auxiliary member  62  is inserted into the guide hole  61  of the movable touch piece  60 , and the connection portion  63   a  is located in the slit portion  61   a  while the latching portion  63   b  is located on the opposite surface to the movable touch piece  60  (surface on the opposite side to the fixed touch piece  38 ). In this state, the latching portion  63   b  of the auxiliary member  62  is in press-contact with the movable touch piece  60 , and energization force thereof is acting so as to cancel part of the elastic force of the movable touch piece  60 . 
         [0080]    According to the electromagnetic relay provided with the movable touch piece  60  and the auxiliary member  62  having the above configuration, in a state where the electromagnet  18  not applying a voltage to the coil  22  is not magnetized, the contacts are held in an open state by the elastic force of the movable touch piece  60 , as shown in  FIG. 17 . At this time, energization force is acting on the movable touch piece  60  so as to cancel the elastic force of the auxiliary member  62  as described above. Therefore, it is possible to alleviate driving force required at the initial stage where the electromagnet  18  is magnetized to rotate the movable iron piece  19 . When the state shifts from immediately before closing of the contacts shown in  FIG. 18  to closing of the contacts shown in  FIG. 19 , the energization force generated by the auxiliary member  62  ceases to act on the movable touch piece  60 . Subsequently, as shown in  FIG. 20 , the movable contact  51  is pressed onto the fixed contact  45 , to obtain a closed state with desired contact pressure. 
         [0081]    Moreover, although the movable touch piece  60  and the auxiliary member  62  come into surface-contact with each other only in the press-fitting portion  46  in one or more of the above embodiments, those are preferably brought into surface-contact at least in a successive part between respective movable contacts  51  (the body portion  47  and the press-fitting portion  46 ). According to this, the conduction part between the movable contacts  51  can be made up of the auxiliary member  40  as well as the movable touch piece  39 . That is, it is possible to increase a sectional area in the conduction part, so as to form a configuration with excellent current supply characteristics. 
         [0082]    Furthermore, although the auxiliary member  40  and the movable touch piece  39 ( 60 ) have been configured of different members in one or more of the above embodiments, those may be integrally configured as shown in  FIG. 21 . That is, the lower edge of the movable touch piece  39  is rotatably connected with the auxiliary member  40 . Specifically, as shown in  FIG. 21A , the lower edge of the movable touch piece  39  is bendably connected with one edge of the auxiliary member  40 , except for a part to become the press-fitting piece  50  in the central portion and the slits formed in two places on both sides thereof. As shown in  FIG. 21B , a part to become the auxiliary member  40  is flexed in the middle, and the leading end portion thereof can come into contact with the movable touch piece  39  by being bent in the bent part. 
         [0083]    According to this configuration, the auxiliary member  40  and the movable touch piece  39  can be integrally processed by pressing and need not be separately managed, thus making subsequent handling thereof convenient. Then, the auxiliary member  40  can be made to exert a desired function just by being bent and press-fitted into the base  1 , and hence assembly processing properties are also excellent. 
         [0084]    Additionally, although the movable touch piece  39 ( 60 ) has been configured such that the pair of movable contacts  51  are conducted and the pair of fixed touch pieces are closed in one or more of the above embodiments, this is not restrictive, but may be configured such that the movable touch piece  39  and the fixed touch piece  38  are regarded as one pair and then two or more pairs of contact switch parts are provided. In short, it is possible to obtain the above effect in the electromagnetic relay by providing the auxiliary member  40  regardless of the difference in shape thereof so long as the electromagnetic relay is configured to drive the movable touch piece  39 . 
         [0085]    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.