Patent Publication Number: US-7710223-B2

Title: Relay

Description:
TECHNICAL FIELD 
   The present invention relates to a relay, in particular, to a high-frequency relay used for broadcast equipment and measurement equipment. 
   BACKGROUND ART 
   Heretofore, as a high-frequency relay, for example, there is the one in which a contact point block 2 is driven with a movable iron piece 5 that is rotated around a rotation shaft 27 so that a contact point is closed and opened (see Patent Documents 1, 2). 
   Patent Document 1: JP2003-257734A 
   Patent Document 2: JP2003-272500A 
   In the above high-frequency relay, as shown in FIG. 4 of Patent Document 1, a pair of protrusions 26, 26 are provided in parallel on one surface of the thick movable iron piece 5 to form a groove portion 28, and a plate spring 29 is screwed and fastened to the protrusions 26, whereby the rotation shaft 27 is supported. 
   DISCLOSURE OF THE INVENTION 
   Problem to be Solved by the Invention 
   However, in the above high-frequency relay, forming the thick movable iron piece 5 with the groove portion 28 requires press work or cutting work. Therefore, a material and a method that can be used are limited, and a degree of design freedom is small. Further, it is not easy to work the movable iron piece 5 and thus there is a problem of low productivity. 
   In view of the above problem, an object of the present invention is to provide a relay having a high degree of design freedom and high productivity. 
   Means of Solving the Problem 
   In order to solve the above problem, in a relay according to the present invention, a supporting shaft is inserted through a shaft hole formed by one surface of a movable iron piece and a plate spring fixed to the one surface of the movable iron piece, the movable iron piece is supported so as to be rotatable, whereby the movable iron piece is rotated around the supporting shaft based on excitation and nonexcitation of a magnetic unit, and both end portions of the plate spring alternately drive a contact point unit, the supporting shaft is inserted through the shaft hole formed by a flat portion of the one surface of the movable iron piece and a bearing portion formed by subjecting the plate spring to bending work, and the movable iron piece is supported so as to be rotatable. 
   EFFECT OF THE INVENTION 
   According to the present invention, since the shaft hole is formed using the bearing portion formed by performing bending work on the plate spring, it is not required that the movable iron piece be subjected to press work and the like. Therefore, the scope of selection of the plate material to be used is broadened, and a degree of design freedom is enhanced. Further, only bending work is performed on the thin plate spring instead of the thick movable iron piece. Therefore, the work is facilitated, and a relay having high productivity is obtained. 
   In an embodiment of the present invention, an inner peripheral surface of the bearing portion of the plate spring may have a curved surface that is brought into line contact with an outer peripheral surface of the supporting shaft. 
   According to the present embodiment, since the supporting shaft is only brought into line contact with the bearing portion of the plate spring, a relay having a small friction and a long lifetime is obtained. 
   In another embodiment of the present invention, the movable iron piece may be urged to the electromagnetic unit side, and an outer peripheral surface of the supporting shaft is brought into line contact with an inner peripheral surface of the bearing portion, and not in contact with the movable iron piece. 
   According to the present embodiment, since the supporting shaft is not brought into contact with the movable iron piece, the friction of the supporting shaft becomes much smaller, and movement of the rotation shaft center is minimized. Therefore, the lifetime of the relay becomes much longer and its operation characteristics are improved. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a coaxial relay showing an embodiment according to the present invention; 
       FIG. 2  is a perspective view showing a state in which a cover is removed from the coaxial relay shown in  FIG. 1 ; 
       FIG. 3  is a cross sectional view of the coaxial relay shown in  FIG. 1  before its operation; 
       FIG. 4  is a cross sectional view of the coaxial relay shown in  FIG. 1  after its operation; 
       FIG. 5  is an exploded perspective view of the coaxial relay shown in  FIG. 1 ; 
       FIG. 6  is a partially enlarged perspective view of the perspective view shown in  FIG. 5 ; 
       FIG. 7  is a partially enlarged perspective view different from the perspective view shown in  FIG. 5 ; 
       FIG. 8A ,  FIG. 8B ,  FIG. 8C  and  FIG. 8D  are a plan view, an elevational view, a bottom view and a perspective view, respectively, of a contact point block  30 ; 
       FIG. 9A ,  FIG. 9B  and  FIG. 9C  are a perspective view, an elevational view and a bottom view, respectively, of a movable iron piece; 
       FIG. 10A  and  FIG. 10B  are a plan view and an elevational view, respectively, which show a self-resetting first spool;  FIG. 10C  and  FIG. 10D  are a plan view and an elevational view, respectively, which show a self-resetting second spool;  FIG. 10E  and  FIG. 10F  are a plan view and an elevational view, respectively, which show a self-holding spool; 
       FIG. 11  is a perspective view for describing an assembling method of a contact point unit; 
       FIG. 12  is a perspective view for describing a method for assembling the movable iron piece to the contact point unit; 
       FIG. 13  is a perspective view for describing a method for attaching a first and second iron cores to the contact point unit; 
       FIG. 14A  and  FIG. 14B  are perspective views for describing an assembling method of a first spool and that of a second spool, respectively; 
       FIG. 15  is a perspective view for describing a method for assembling a yoke to the first and second spools; 
       FIG. 16  is a perspective view for describing a method for assembling a permanent magnet to the first and second spools; 
       FIG. 17  is a perspective view for describing a method for assembling an electromagnetic unit to the contact point unit; 
       FIG. 18A  and  FIG. 18B  are perspective views for describing an assembling method of a control unit; 
       FIG. 19  is a perspective view for describing an method for assembling a terminal stand and an electronic component to a printed circuit board; 
       FIG. 20  is a perspective view for describing a method for assembling the control unit to the electromagnetic unit; 
       FIG. 21  is a perspective view for describing a method for assembling the cover to the contact point unit and the electromagnetic unit; 
       FIG. 22A ,  FIG. 22B  and  FIG. 22C  are an upper perspective view, a bottom view and a lower perspective view, respectively, which show a case in which an engagement recess is formed in a straight line shape in a caulk opening of a movable contact point;  FIG. 22D ,  FIG. 22E  and  FIG. 22F  are an upper perspective view, a bottom view and a lower perspective view, respectively, which show a case in which an engagement recess is formed in a cross shape in a caulk opening of a movable contact point; and 
       FIG. 23A  and  FIG. 23B  are perspective views and  FIG. 23C  is a bottom view, which are provided for describing another method for attaching the movable contact point to a plunger. 
   

   DESCRIPTION OF THE NUMERALS 
   
       
         10 : contact point unit 
         11 : base block 
         12 : escape groove 
         13 ,  14 ,  15 : through holes for coaxial connectors 
         16   a ,  16   b : positioning pins 
         18 ,  19 : attachment through holes 
         21 ,  22 ,  23 : coaxial connectors 
         21   a ,  22   a ,  23   a : fixed contact points 
         24 : copper sheet 
         30 : contact point block 
         31 : contact point base 
         31   a ,  31   b : operation holes 
         32 ,  33 ,  34 ,  35 : supporting posts 
         36 ,  37 : supporting walls 
         36   a ,  36   b ,  36   c ,  37   a ,  37   b ,  37   c : positioning projections 
         36   d ,  37   d : position restricting protrusions 
         36   e ,  37   e : shaft holes 
         41 ,  42 : coil springs 
         43 ,  44 : plungers 
         45 ,  46 : movable contact points 
         45   a ,  46   a : caulk openings 
         45   b : engagement recess 
         50 : movable iron piece 
         53 : plate spring 
         55 : bearing portion 
         55   a : shaft hole 
         56 ,  57 : elastic arm portions 
         58 : supporting shaft 
         60 : electromagnetic unit 
         61 ,  65 : self-resetting type first, second spools 
         61   a ,  61   a : body portions 
         61   b ,  65   b : through holes 
         62 ,  63 ,  66 ,  67 : flange portions 
         62   a ,  66   a : positioning tongues 
         64 ,  68 : positioning walls 
         69 : self-holding spool 
         71 ,  73 : coils 
         72   a ,  72   b ,  74   a ,  74   b : coil terminals 
         75 : yoke 
         75   a ,  75   b : arm portions 
         76 ,  77 : first, second iron cores 
         76   a ,  77   a : vertical portions 
         79 : permanent magnet 
         80 : control unit 
         81 : printed circuit board 
         82 : terminal stand 
         83 - 87 : input/output terminals 
         88 : electronic component 
         90 : cover 
         91 ,  92 : elongate openings 
     
  
   BEST MODE FOR CARRYING OUT THE INVENTION 
   A coaxial relay that is an embodiment to which the present invention has been applied will be described with reference to the accompanying drawings of  FIG. 1  to  FIG. 23 . 
   The coaxial relay of the present embodiment is generally constructed of a contact point unit  10 , a movable iron piece  50 , an electromagnetic unit  60 , a control unit  80  and a cover  90 . 
   The contact point unit  10  is constructed of a base block  11 , a copper sheet  24  and a contact point block  30 . As shown in  FIG. 6 , the base block  11  is a rectangular parallelepiped, and an escape groove  12  is formed in a central portion of an upper surface of the base block  11 . A pair of positioning pins  16   a ,  16   b  are protrusively provided so as to be point symmetrical with each other, and a pair of screw holes  17   a ,  17   b  are formed so as to be point symmetrical with each other around the escape groove  12  of the base block  11 . However, the positioning pins  16   a ,  16   b  and the screw holes  17   a ,  17   b  are not disposed in positions that are line symmetrical with each other in order to determine the assembling direction of the contact point block  30 . Through holes  13 ,  14 ,  15  for coaxial connectors are formed in the escape groove  12  at an equal pitch. An inner peripheral surface on a bottom surface side of each of the through holes  13 ,  14 ,  15  is provided with a female screw portion for a coaxial connector. Therefore, coaxial connectors  21 ,  22 ,  23  are screwed and fixed to the through holes  13 ,  14 ,  15 , whereby fixed contact points  21   a ,  22   a ,  23   a  protruding respectively from tips of the coaxial connectors  21 ,  22 ,  23  are positioned in the escape groove  12 . Further, attachment through holes  18 ,  19  for fixing the base block  11  itself to another place are provided in side surfaces of the base block  11 . 
   In a contact point block  30 , a central portion of an upper surface of a contact point base  31  is provided with a pair of operation holes  31   a ,  31   b  as shown in  FIG. 7 . Upper opening edge portions of the operation holes  31   a ,  31   b  are provided with annular step portions for positioning coil springs  41 ,  42 , respectively, described below. Further, as shown in  FIG. 8 , in proximity of the operation holes  31   a ,  31   b , positioning holes  38   a ,  38   b  are provided, and fixing holes  39   a ,  39   b  are provided. Further, supporting posts  32 ,  33 ,  34 ,  35  are protrusively provided at corner portions of the upper surface of the contact point base  31 . A supporting wall  36  is protrusively provided between the supporting posts  32  and  34 , and a supporting wall  37  is protrusively provided between the supporting posts  33  and  35 . Upper end surfaces of the supporting walls  36 ,  37  are respectively protrusively provided with positioning projections  36   a ,  36   b ,  36   c  and  37   a ,  37   b ,  37   c . Further, position restricting protrusions  36   d ,  37   d  are provided at basal portions of opposite surfaces of the supporting walls  36 ,  37 . Moreover, shaft holes  36   e ,  37   e , which are located on the same horizontal shaft center, are provided in the supporting walls  36 ,  37 . Of an outer surface of the supporting wall  36 , an opening edge portion of the shaft hole  36   e  is provided with an annular step portion, which serves as a mark in assembling as well as is used for securing a pushing margin. 
   Generally truncated conical shaped coil springs  41 ,  42 , which are positioned with respect to the annular step portions of the operation holes  31   a ,  31   b , respectively, and plungers  43 ,  44 , whose cross sections are generally T-shaped, and whose shaft portions  43   a ,  44   a  are inserted into the centers of the coil springs  41 ,  42 , respectively, are assembled to the contact point base  31 . Lower end portions of the plungers  43 ,  44 , which protrude from the operation holes  31   a ,  31   b , are fitted into caulk openings  45   a ,  46   a , which have a generally rectangular shape in plan view, of movable contact points  45 ,  45 , respectively, and fixed by caulking. Thereby, the plungers  43 ,  44  are urged upward and supported on the contact point base  31  so as to be movable up and down. 
   As shown in  FIG. 22 , for example, an engagement recess  45   b , which is formed in a lower opening edge portion of the caulk opening  45   a  of the movable contact point  45 , may be formed in a straight line shape ( FIGS. 22A-22C ) or a cross shape ( FIGS. 22D-22F ) by press work. The reason therefor is that, by engaging a resin solidified by thermal caulking, free rotation of the movable contact point  45  is prevented. 
   Further, as shown in  FIG. 23 , for example, a tip end face of the shaft portion  43   a  of the plunger  43  is protrusively provided with a tip end portion  43   c  having an elliptical shape in cross section, and a pair of engagement claws  43   d ,  43   d  are protrusively provided on both sides of the tip end portion  43   c . Then, the caulk opening  45   a  of the movable contact point  45  is fitted over the tip end portion  43   c , and thermal caulking is performed to fix the movable contact point  45 , whereby free rotation of the movable contact point  45  may be prevented. Furthermore, the movable contact points  45 ,  46  may be fixed to the plungers  43 ,  44  by an adhesive or insert molding. 
   As shown in  FIG. 9 , the movable iron piece  50  is a plate material having a generally rectangular shape in plan view, and caulk openings  54  of a plate spring  53  subjected to bending work are fitted over a pair of projections  51 ,  51  protrusively provided on a central portion of a lower surface of the movable iron piece  50 , and then fixed by caulking, whereby a shaft hole  55   a  is formed by one surface of the movable iron piece  50  and a bearing portion  55 . The plate spring  53  is formed symmetrically, with the bearing portion  55  supporting a supporting shaft  58  as the center. Therefore, the movable iron piece  50 , to which the plate spring  53  has been caulk-fixed, is positioned between the supporting walls  36 ,  37 , and the supporting shaft  58  is inserted through the shaft holes  36   e ,  37   e  of the contact point block  30  and the shaft hole  55   a  formed by the movable iron piece  50  and the plate spring  53 , whereby the movable iron piece  50  is supported so as to be freely rotatable. As a result, it becomes possible for flexible arm portions  56 ,  57  of the plate spring  53  to alternately come in contact with the first and second plungers  43 ,  44  of the contact point block  30 . 
   According to the present embodiment, a circular arc surface of the bearing portion  55  that forms the shaft hole  55   a  has a larger radius than that of the supporting shaft  58 . Therefore, the supporting shaft  58  is brought into line contact with the bearing portion  55  of the plate spring  53 , resulting in small friction. Thus, a relay having excellent operation characteristics is obtained. In addition, the shape of the bearing portion  55  of the plate spring  53  is not limited to the arc shape in cross section. The supporting shaft  58  may be brought into line contact with the bearing portion  55  by forming the circular arc surface of the bearing portion  55  in a triangular shape in cross section or a square shape in cross section, for example. 
   The electromagnetic unit  60  is constructed of a self-resetting first and second spools  61 ,  65  around which coils  51 ,  71  are wound, respectively, a yoke  75 , a first and second iron cores  76 ,  77  and a permanent magnet  79 . 
   As shown in  FIGS. 10A ,  10 B and  FIG. 14A , of flange portions  62 ,  63  integrally formed on both ends of a cylindrical body portion  61   a  of the self-resetting first spool  61 , a leader line of a coil  71  wound on the body portion  61   a  is tied and soldered to horizontal end portions of a pair of generally L-shaped coil terminals  72   a ,  72   b , which are inserted into one flange portion  62 . Further, a positioning tongue  62   a  for holding a permanent magnet  79  protrudes laterally from an inward side edge portion of the flange portion  62 , and positioning walls  64 ,  64  respectively protrude upward from both side edge portions of an upper surface of the flange portion  62 . Furthermore, an inward side edge portion of the flange portion  63  is provided with a notch portion  63   a  for positioning the permanent magnet  79 . 
   As shown in  FIGS. 10C ,  10 D and  FIG. 14B , of flange portions  66 ,  67  integrally formed on both ends of a cylindrical body portion  65   a  of the self-resetting second spool  65 , a leader line of a coil  73  wound on the body portion  65   a  is tied and soldered to horizontal end portions of a pair of generally L-shaped coil terminals  74   a ,  74   b , which are inserted into one flange portion  66 . Further, a positioning tongue  66   a  for holding the permanent magnet  79  protrudes laterally from an inward side edge portion of the flange portion  66 , and positioning walls  68 ,  68  respectively protrude upward from both side edge portions of an upper surface of the flange portion  66 . Furthermore, an inward side edge portion of the flange portion  67  is provided with a notch portion  67   a  for positioning the permanent magnet  79 . 
   The reason why the flange portions  62 ,  66  of the first and second spools  61 ,  65  are not configured to be symmetrical is that the permanent magnet  79 , which will be described below, is not supported at the center but at an eccentric position whereby a magnetic balance is disturbed to construct a self-resetting type relay. 
   If a self-holding type relay is constructed, for example, a coil may be wound on a body portion  69   a  of a self-holding spool  69  as shown in  FIGS. 10E ,  10 F to be used. A positioning tongue  62   b  and a notch portion  63   b  of the spool  69  have an outer shape for supporting the permanent magnet  79  at the center. 
   A yoke  75  has a generally U-shape in cross section, and its both side arm portions  75   a ,  75   b  are press-fitted into the cylindrical bodies  61   a ,  65   a  of the first and second spools  61 ,  65 , respectively, whereby the first spool  61  and the second spool  65  are joined and integrated. The yoke  75  is provided to construct a magnetic circuit together with first and second iron cores  76 ,  77  described below. 
   As shown in  FIG. 13 , the first and second iron cores  76 ,  77  have a generally L-shape in cross section, and are directly fixed to upper end surfaces of the supporting posts  32 ,  33  and  34 ,  35  of the contact point base  31  with screws  78   a ,  78   b  and  78   c ,  78   d , respectively. Accordingly, the first and second iron cores  76 ,  77  are assembled to the contact point base  31  with high assembling accuracy. Vertical portions  76   a ,  77   b  of the first and second iron cores  76 ,  77  are inserted into through holes  61   b ,  65   b  of the cylindrical body portions  61   a ,  65   b  of the first, second spools  61 ,  65 , respectively, so as to be brought into surface contact with both of the arm portions  75   a ,  75   b , thus constructing a magnetic circuit. 
   As shown in  FIG. 19 , a control unit  80  is constructed by mounting a terminal stand  82  and an electronic component  88  on a printed circuit board  81 . 
   As shown in  FIG. 18 , input/output terminals  83  to  87  are press-fitted into terminal holes  82   a  to  82   e , respectively, of the terminal stand  82  from an upper side so as to be protruded to a lower side thereof, and a seal material is injected and solidified to fix the input/output terminals. Terminal portions of the input/output terminals  83  to  88  that protrude from the lower side of the terminal stand  82  are respectively electrically connected to the printed circuit board ( FIG. 20 ). 
   As the electronic component  88 , for example, a small relay for monitor output is given. 
   A cover  90  has a box shape that can be fitted over the base block  11  of the contact point unit  10  on which the electromagnetic unit  60  is mounted, and two elongate openings  91 ,  92  for input/output terminals are provided in a ceiling surface thereof. 
   A method for assembling the above components will be described. 
   First, as shown in  FIG. 11 , the coaxial connectors  21 ,  22 ,  23  are screwed into the through holes  13 ,  14 ,  15 , respectively, and integrated therewith. 
   On the other hand, the coil springs  41 ,  42  are positioned with respect to the step portions of the operation holes  31   a ,  31   b  provided in the contact point base  31 , respectively, and the shaft portions  43   a ,  44   a  of the plungers  43 ,  44  having the generally T-shape in cross section are inserted therethrough. Then, the protruding lower end portions of the plungers  43 ,  44  are fitted into the caulk openings  45   a ,  45   b  of the movable contact points  45 ,  46  and fixed by caulking. 
   According to the present embodiment, the arm portions  43   b ,  44   b  of the plungers  43 ,  44  come in contact with the position restricting protrusions  36   d ,  37   d  provided at the basal portions of the opposite surfaces of the supporting walls  36 ,  37  of the contact point base  31 , respectively, so that their positions are restricted (see  FIG. 8A ). Thus, the movable contact points  44 ,  45  are accurately brought into contact with the fixed contact points  21   a ,  22   a ,  23   a  without rotation of the plungers  43 ,  44 , and the movable contact points  44 ,  45 . Therefore, there is an advantage that contact reliability is high. In addition, the position restricting means for the plungers  43 ,  44  may be protrusively provided at other portions of the contact point base  31 . 
   Subsequently, the positioning holes  38   a ,  38   b  of the contact point base  31  are inserted to the positioning pins  16   a ,  16   b  of the base block  11  so as to hold the copper sheet  24 . The copper sheet  24  performs magnetic shielding, so that high-frequency characteristics can be improved. Then, screws  47   a ,  47   b  are screwed into the screw holes  17   a ,  17   b  of the base block  11  from the fixing holes  39   a ,  39   b  of the contact point base  31 , respectively, whereby the contact point unit  10  is completed. 
   Then, as shown in  FIG. 12 , by placing the movable iron piece  50  between the supporting walls  36 ,  37  of the contact point base  31 , and inserting the supporting shaft  58  into the shaft holes  36   e ,  37   e  of the supporting walls  36 ,  37  and the shaft hole  55   a  of the movable iron piece  50 , the movable iron piece  50  is supported so as to be rotatable. 
   Next, as shown in  FIG. 13 , the first iron core  76  is positioned with respect to the upper surfaces  32 ,  33  of the contact point base  31  through a shielding plate  48 , and fixed with the screws  78   a ,  78   b . Similarly, the second iron core  78  is positioned with respect to the upper surfaces  34 , of the contact point base  31 , and fixed with the screws  78   c ,  78   d . Positioning of the first and second iron cores  76 ,  77  may be performed with jigs not shown. Further, if required, the shielding plate may be placed on both sides of the contact point base  31 . 
   On the other hand, as shown in  FIG. 14A , after inserting the coil terminals  72   a ,  72   b  into the flange portion  62  of the first spool  61  from a lateral side, the leader line of the coil  71  wound on the body portion  61   a  is tied to the protruding horizontal end portions of the coil terminals  72   a ,  72 , and then soldered. Similarly, as shown in  FIG. 14B , after inserting the coil terminals  74   a ,  74   b  into the flange portion  66  of the second flange  65  from a lateral side, the leader line of the coil  73  wound on the body portion  65   a  is tied to the protruding horizontal end portions of the coil terminals  74   a ,  74   b , and then soldered. 
   Thereafter, as shown in  FIG. 15 , the first and second spools  61 ,  65  are positioned. Then, the arm portions  75   a ,  75   b  of the yoke  75  are press-fitted into the through holes  61   b ,  65   b  of the cylindrical body portions  61   a ,  65   a , respectively, so that they are integrated. After that, as shown in  FIG. 16 , the permanent magnet  79  is inserted between the positioning tongues  62   a ,  66   a  of the first and second spools  61 ,  65  as well as between the notch portions  63   a ,  67   a  of the flange portions  63 ,  67 , whereby an upper end surface of the permanent magnet  79  is attracted to a lower surface of the yoke  75 . 
   Furthermore, as shown in  FIG. 17 , the vertical portions  76   a ,  77   b  of the first and second iron cores  76 ,  77  assembled to the contact point unit  10  are inserted into the through holes  61   b ,  65   b  of the cylindrical body portions  61   a ,  65   b  of the first, second spools  61 ,  65 , respectively, whereby the arm portions  75   a ,  75   b  of the yoke  75  and the vertical portions  76   a ,  77   b  of the first and second spools are brought into surface contact with each other (see  FIGS. 2 and 3 ). Therefore, the movable iron piece  50  is attracted to a lower end surface of the permanent magnet  79  in a manner so as to be rotatable. Then, a seal material is injected into the through holes  61   b ,  65   b  to be solidified, whereby the arm portions  75   a ,  75   b  and the vertical portions  76   a ,  77   a  are joined to be integrated, so that the electromagnetic block  60  is fixed to the contact point unit  10 . 
   According to the present embodiment, since the movable iron piece  50  is attracted to the lower end surface of the permanent magnet  79  so as to be rotatable, and the elastic arm portions  56 ,  57  of the plate spring  53  urge the plungers  43 ,  44  downward, the movable iron piece  50  is in a state of being pressed upward. On the other hand, the supporting shaft  58  is inserted through the shaft holes  36   e ,  37   e  of the supporting walls  36 ,  37  to be supported. Therefore, the supporting shaft  58  does not come in contact with the movable iron piece  50 , and a lower surface of the supporting shaft  58  is always in line contact with an inner peripheral surface of the bearing portion  55 . Using the contact portion as a fulcrum, the movable iron piece  50  is supported so as to be rotatable. As a result, since the plate spring  53  is brought into line contact with the supporting shaft  58 , there is an advantage that a relay which has a small friction, a long lifetime and good operation characteristics with less movement of the rotation shaft center is obtained. 
   Further, according to the present embodiment, since the contact point base  31 , which has the shaft holes  36   e ,  37   e , and whose upper and lower surfaces serve as reference surfaces, is held by the base block  11  and the electromagnetic block  60 , there is an advantage that high assembling accuracy can be secured and that a relay having excellent operation characteristics is obtained. 
   By bending the arm portions  56 ,  57  of the plate spring  53  from gaps between the supporting posts  32 ,  33 ,  34 , and the supporting walls  36 ,  37  of the contact point base  31 , adjustment of the operation characteristics is performed. 
   Therefore, according to the present embodiment, since the adjustment of the operation characteristics can be performed by bending the elastic arm portions  56 ,  57  of the plate spring  53  from the gaps, there is an advantage that a relay with high operability and a high manufacturing yield is obtained. 
   Thereafter, the printed circuit board  81  on which the terminal stand  82  and the electronic component  88  are mounted is placed on the positioning walls  64 ,  68  of the flange portions  62 ,  66 , and electrically connected to vertical upper end portions of the coil terminals  72   a ,  72   b  and  74   a ,  74   b  of the electromagnetic unit  80 ,  50  that they are integrated. 
   By fitting the cover  90  over the contact point unit  10  on which the electromagnetic unit  60  is mounted, the input/output terminals  83  to  88  are protruded from the elongate openings  91 ,  92 . Then, the seal material is injected into notch portions provided in opening edge portions of the cover  90  to be solidified, thus sealing the notch portions. 
   Next, operation of the coaxial relay will be described. 
   First, as shown in  FIG. 3 , if a voltage is not applied to the coils  71 ,  73 , since the permanent magnet  79  is not located at the center, and the magnetic balance is disturbed by placing the shielding plate  48  on one side, the other end portion  50   b  of the movable iron piece  50  is attracted to the second iron core  77 . Therefore, the elastic arm portion  56  of the plate spring  53  presses the plunger  43  downward against a spring force of the coil spring  41 . As a result, both end portions of the movable contact point  45  are respectively brought into press contact with the fixed contact points  21   a ,  22   a  respectively to close an electrical circuit. 
   Then, if a voltage is applied to the coils  71 ,  73  so that one end portion  50   a  of the movable iron piece  50  is attracted, the other end portion  50   b  of the movable iron piece  50  repulses the second iron core  77 , and said one end portion  50   a  is attracted to the first iron core  76 . Therefore, the movable iron piece  50  is rotated using as a fulcrum a portion where a lower end surface of the supporting shaft  58  assembled to the movable iron piece  50  and an inner peripheral surface of the shaft hole  55  are brought into line contact with each other. As a result, after the elastic arm portion  56  of the plate spring  53  has separated from the plunger  43 , the elastic arm portion  57  presses down the plunger  44  against a spring force of the coil spring  42 . Therefore, after both of the end portions of the movable contact point  45  have separated from the fixed contact points  21   a ,  22   a , both end portions of the movable contact point  46  are attracted to the fixed contact points  22   a ,  23   a.    
   If a voltage applied to the coils  71 ,  73  is disconnected, the right and left magnetic balance of the movable iron piece  50  is disrupted, so that the resultant force of the coil spring  42  and the plate spring  53  becomes relatively larger than the magnetic force of the permanent magnet  79 . Therefore, the other end portion  50   b  of the movable iron piece  50  is attracted to the second iron core  77 , and the movable iron piece  50  is rotated using the lower end surface of the supporting shaft  58  as a fulcrum. As a result, the elastic arm portion  57  of the plate spring  53  is separated from the plunger  44 , and the elastic arm portion  56  presses down the plunger  43 . Then, after both of the end portions of the movable contact point  46  have separated from the fixed contact points  22   a ,  23   a , both of the end portions of the movable contact point  45  are brought into press contact with the fixed contact points  21   a ,  22   a  so as to recover to the original state. 
   Although the self-resetting type relay was described in the present embodiment, for example, using a pair of self-holding type spools  69  as shown in  FIG. 10E  and  FIG. 10F , the permanent magnet  79  is held at the center to construct the self-holding type relay. 
   INDUSTRIAL APPLICABILITY 
   The coaxial relay of the present invention is not limited to the above mentioned embodiment, and it can be applied to other relays.