Patent Publication Number: US-8111117-B2

Title: Electromagnetic relay

Description:
TECHNICAL FIELD 
     The present invention relates to an electromagnetic relay, in particular to an attachment structure of a card for driving a contact mechanism portion. 
     BACKGROUND ART 
     Conventionally, as an electromagnetic relay, for example, there is one wherein, based on excitation and non-excitation of an electromagnetic assembly X, a movable contact spring  9  is rotated by a card  12  that makes a reciprocating movement by rotation of an armature  7  to open/close contacts (refer to Patent Document 1). 
     In the above electromagnetic relay, engagement portions  12   a ,  12   b  protruding sideways from one end side of the card  12  are engaged with notch portions  7   b ,  7   c  of the armature  7  so as to be supported. 
     Patent Document 1: JP4-272628A 
     DISCLOSURE OF INVENTION 
     Problem to be Solved by the Invention 
     However, in the above electromagnetic relay, as shown in  FIGS. 1 and 2  of the Patent Document 1, one side of a frame portion of the card  12  located at a basal portion of the engagement portions  12   a ,  12   b  is disposed directly overhead between a magnetic pole portion of an iron core  4  and the movable iron piece  7 . Therefore, in the above electromagnetic relay, adjustment cannot be made by inserting a thickness gauge when adjusting operation characteristics, so that adjustment work requires a lot of time and effort, and there is a problem that variations in operation characteristics tend to increase. 
     In view of the above problem, an object of the present invention is to provide an electromagnetic relay whose operation characteristics are easily adjusted and in which variations in the operation characteristics are small. 
     Means of Solving the Problem 
     In order to solve the above problem, in an electromagnetic relay of the present invention, one end portion of a frame-shaped card is engaged with a movable iron piece that is rotated by being attracted to and separated from a magnetic pole portion of an iron core based on excitation and non-excitation of an electromagnetic block formed by winding a coil around the iron core, and a contact mechanism portion is driven by the other end portion of the frame-shaped card that makes a reciprocating movement so as to open/close contacts,
         a pair of protrusions are protrusively provided on the same shaft center inside of the one end portion of the frame-shaped card, both side edge portions of the movable iron piece are held by the one end portion of the card and the protrusions, and an adjustment opening is provided between the protrusions.
 
Effect of the Invention
       

     According to the present invention, since the adjustment opening is provided between the protrusions provided on the same shaft center inside of the card, by inserting a thickness gauge into the adjustment opening, adjustment work of the operation characteristics is facilitated and an electromagnetic relay having the good operation characteristics is obtained. 
     In another electromagnetic relay of the present invention, one end portion of a frame-shaped card is engaged with a movable iron piece that is rotated by being attracted to and separated from a magnetic pole portion of an iron core based on excitation and non-excitation of an electromagnetic block formed by winding a coil around the iron core, and a contact mechanism portion is driven by the other end portion of the frame-shaped card that makes a reciprocating movement so as to open/close contacts,
         a pair of protrusions are protrusively provided on the same shaft center inside of the one end portion of the frame-shaped card, and the center of the one end portion of the card is provided with a slit, whereby both side edge portions of the movable iron piece are held by the one end portion of the card and the protrusions, and an adjustment opening may be provided between the protrusions.       

     According to the present invention, in addition to the above effect, by the slit provided in the center of the one end portion of the card, the one end side of the card is easily elastically deformed, so that assembling of the movable iron piece is facilitated. 
     In an embodiment of the present invention, an upper end edge portion of the movable iron piece may be provided with an engagement pawl engaged with the one end portion of the frame-shaped card. 
     According to the present embodiment, the movable iron piece is engaged with the frame-shaped card so as to prevent the frame-shaped card from coming off, so that reliability is improved. 
     In another embodiment of the present invention, intermediate portions on both opposite sides of the frame-shaped card may be bridged over by a connection portion. 
     According to the present embodiment rigidity of the frame-shaped card is improved so that it is hardly deformed. Therefore, there is an effect that operation characteristics are improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  and  FIG. 1B  are perspective views respectively showing a first embodiment of the electromagnetic relay of the present invention from different angles; 
         FIG. 2  is an exploded perspective view of the electromagnetic relay shown in  FIG. 1 ; 
         FIG. 3A  and  FIG. 3B  are a side cross sectional view and a front cross sectional view, respectively, of the electromagnetic relay shown in  FIG. 1 ; 
         FIG. 4A  and  FIG. 4B  are perspective views for describing an assembling method of a hinge spring, and  FIG. 4C  is a perspective view of the hinge spring; 
         FIG. 5A  is a perspective view of a base shown in  FIG. 1 ,  FIG. 5B  is a perspective view showing a state in which a yoke is assembled to the base, and  FIG. 5C  is a perspective view showing a state in which a coil is disposed on the base; 
         FIG. 6A  and  FIG. 6B  are perspective views for describing an adjustment method using a thickness gauge; 
         FIG. 7  is a perspective view showing a spool and a hinge spring according to a second embodiment; and 
         FIG. 8A  and  FIG. 8B  are perspective views showing a card and an electromagnetic relay, respectively, according to a third embodiment. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS 
       10 : base 
       11 : cylindrical-shaped cover 
       12 : engagement pawl 
       20 : electromagnetic block 
       22 : spool 
       23 : body portion 
       24 ,  25 : flange portion 
       26 : pedestal portion 
       26   a : insertion opening 
       27 : receiving portion 
       30 : iron core 
       31 : magnetic pole portion 
       32 : the other end portion 
       35 : coil terminal 
       40 : yoke 
       41 : vertical portion 
       42 : caulking hole 
       43 : thin neck portion 
       44 : horizontal portion 
       45 : shallow groove 
       50 : movable iron piece 
       52 : upper side portion 
       53 : engagement pawl 
       60 : hinge spring 
       61 : horizontal portion 
       62 : positioning rib 
       62   a : elastic pawl portion 
       63 : press-fitting elastic tongue piece 
       65 : vertical portion 
       66 : supporting elastic tongue piece 
       70 : contact mechanism portion 
       71 : normally-closed fixed contact terminal 
       72 : normally-closed fixed contact 
       73 : normally open fixed contact terminal 
       74 : normally open fixed contact 
       71   a ,  73   a ,  75   a : press-fitting portion 
       75 : movable contact terminal 
       76 : movable contact piece 
       77 : movable contact 
       80 : card 
       81 : connection portion 
       82 : pressing arm portion 
       82   a : engagement projection 
       83 : engagement recess 
       83   a : slit 
       84 : protrusion 
       85 : adjustment opening 
       90 : case 
       91 : thickness gauge 
       92 : gauge portion 
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described in accordance with the accompanying drawings of  FIGS. 1 to 8 . 
     A first embodiment is generally constructed of a base  10 , an electromagnetic block  20 , a movable iron piece  50 , a contact mechanism portion  70 , a card  80  and a case  90  as shown in  FIGS. 1 to 6 . 
     The base  10  is obtained by integrally molding at its upper surface central portion a cylindrical-shaped cover  11  provided with a partition wall at its back side. The base  10  has a structure that allows the electromagnetic block  20  described below to slide from one side so that it can be assembled thereto. Further, both upper surface side edge portions on the opening side of the cylindrical-shaped cover  11  of the base  10  are respectively provided with engagement pawls  12 ,  12  protruding therefrom for being engaged with both upper surface side edge portions of a yoke  40  described below. 
     In the electromagnetic block  20 , a coil  21  is wound around a body portion  23  of a spool  22  having flange portions  24 ,  25  at its both ends. Then, an iron core  30  having a generally T-shape in cross section is inserted into a through hole  23   a  in the body portion  23 , one end portion thereof that protrudes serves as a magnetic pole portion  31 , and the other end portion  32  that protrudes is fixed by caulking to a vertical portion  41  of the yoke  40  described below. 
     Both side edge portions of the one side flange portion  24  are respectively provided with pedestal portions  26 ,  26  protruding therefrom, and lower side edge portions of the pedestal portions  26 ,  26  are connected with a receiving portion  27 . An insertion opening  26   a  through which a horizontal portion  44  of the yoke  40  can be inserted is provided between the receiving portion  27  and the flange portion  24 . Further, coil terminals  35 ,  35  are respectively press-fitted into the pedestal portions  26 ,  26 , and lead-out wires of the coil  21  are tied and soldered to upper end portions of the coil terminals  35  that protrude therefrom. 
     The yoke  40  is made of a magnetic material generally having an L-shape. A vertical portion  41  thereof is formed with a caulking hole, and a shallow groove  45  having an arc shape in cross section along an outer peripheral surface of the coil  21  is formed in the upper surface center of the horizontal portion  44  along a lengthwise direction. Further, a basal portion of the vertical portion  41  is formed with a thin neck portion  43  having a narrow width. Therefore, there is an advantage that bending work is facilitated. 
     Then, the horizontal portion  44  of the yoke  40  is inserted through the insertion opening  26   a , and the other end portion  32  of the iron core  30  is caulk-fixed to the caulking hole  42 , whereby the yoke  40  is integrated with the spool  22 . Therefore, a tip end surface of the horizontal portion  44  of the yoke  40  is exposed from the insertion opening  26   a  ( FIG. 3 ). 
     As shown in  FIG. 2 , the movable iron piece  50  is made of a plate-shaped magnetic material formed by press work. Its outer surface is protrusively provided with an engagement protrusion  51  by protruding work, and an extended upper side portion  52  is formed with an engagement pawl  53 . The movable iron piece  50  is rotatably supported between the pedestal portions  26 ,  26  of the spool  22  through a hinge spring  60 , and a lower end edge portion of the movable iron piece  50  comes in contact with the tip end surface of the horizontal portion  44  of the yoke  40  ( FIG. 3 ). 
     As shown in  FIG. 4 , the hinge spring  60  is formed of a thin plate spring material that is bent in a generally L-shape, and positioning ribs  62 ,  62  are formed by cutting and raising both side edge portions of a horizontal portion  61 . Further, each positioning rib  62  is formed with an elastic pawl portion  62   a  so as to prevent the hinge spring  60  from coming off. Also, a press-fitting elastic tongue piece  63  is cut and raised at the center of the horizontal portion  61 , and an assembling tongue piece  64  is cut at a cornered portion of the hinge spring  60 . On the other hand, the center of a supporting elastic tongue piece  66 , which is cut out of a vertical portion  65  of the hinge spring  60 , is provided with a caulking hole  66   a . In  FIG. 4 , the coil  21  and the movable iron piece  50  are not shown for the sake of convenience of the description. 
     Thereafter, after the engagement protrusion  51  of the movable iron piece  50  is caulk-fixed to the caulking hole  66   a , the horizontal portion  61  of the hinge spring  60  is press-fitted into a gap between a bottom surface of the horizontal portion  44  of the yoke  40  and the receiving portion  27  with the assembling tongue piece  64  of the hinge spring  60  being held, and each positioning rib  62  is press-fitted into the gap  26   a  between a side surface of the yoke  40  and each pedestal portion  26 . As a result, the positioning rib  62  that comes out from the gap  26   a  between the side surface of the yoke  40  and the pedestal portion  26  is engaged with a notched step portion  45   a  of the yoke  40 , and the elastic pawl portion  62   a  is locked to an edge portion of the pedestal portion  26 , so that the movable iron piece  50  is prevented from coming off. Thereby, the movable iron piece  50  is rotatably supported by the hinge spring  60 , and the electromagnetic block  20  is completed. 
     In the present embodiment, the positioning ribs  62  and the gap  26   a  can be visually checked at the same time and thus there is an advantage that assembling work is facilitated. 
     The contact mechanism portion  70  is disposed on one side of the cylindrical-shaped cover  11  of the base  10 , and consists of normally-closed, normally open fixed contact terminals  71 ,  73  and a movable contact terminal  75 . The normally-closed, the normally open fixed contact terminals  71 ,  73  are obtained by continuously integrally molding press-fitting portions  71   a ,  73   a  and terminal portions  71   b ,  73   b , respectively, at lower sides of fixed contacts  72 ,  74 . In particular, the press-fitting portion  71   a  of the normally-closed side fixed contact terminal  71  is bent generally at right angles. 
     In the movable contact terminal  75 , a connection portion of a movable contact piece  76  formed by being punched in a generally J-shape  76   a  is bent generally at right angles to form a rib portion  76   a  serving as a rotational fulcrum, and a movable contact  77  is caulk-fixed to a free end portion thereof. Further, right above the movable contact  77 , a protrusion  82   a  of a card  80  described below is inserted, and an engagement opening  76   b  serving as a point of action is formed. Therefore, a shaft center of the engagement opening  76   b  and a shaft center of the movable contact  77  are located on the same vertical surface. 
     In the movable contact terminal  75 , a press-fitting portion  75   a  located at a basal portion of the movable contact piece  76  is press-fitted sideways into a slit  13 , which is provided in one side edge portion of the base  10 , whereby a terminal portion  75   b  is protruded from a bottom surface of the base  10 . Further, the press-fitting portions  71   a ,  73   a  of the normally-closed, normally open fixed contact terminals  71 ,  73  are press-fitted sideways into a pair of slits  14 ,  15 , respectively, which are provided in an edge portion on the opposite side of the slit  13  for the movable contact terminal. Thereby, the terminal portions  71   b ,  73   b  are protruded from the bottom surface of the base  10 , and the movable contact  77  and the fixed contacts  72 ,  74  are opposite to each other so that they can be respectively contacted with and separated from each other. 
     Subsequently, both the side edge portions of the horizontal portion  44  of the yoke  40  are inserted in a sliding manner so as to be engaged with the pair of the engagement pawls  12 ,  12 , and a part of the electromagnetic block  20  is inserted into the cylindrical-shaped cover  11 , whereby the base  10  and the electromagnetic block  20  are integrated with each other. 
     The card  80  is for connecting the movable iron piece  50  and the movable contact terminal  75 . It has a rectangular frame shape in plan view, and its middle portion is provided with a connection portion  81 . In particular, frame portions in a lengthwise direction each have a generally triangular shape in cross section (refer to  FIG. 3B ), and therefore a dead space can be effectively used, so that there is an advantage that the entire device can be reduced in size. Further, the card  80  is provided sideways with an engagement projection  82   a  protruding from the center of a tip end surface of a pressing arm portion  82 , which is provided protruding from the center of a tip end surface of one end side of the card  80 . Further, a central portion of the other end side of the card  80  is formed with an engagement recess  83 , and a pair of protrusions  84 ,  84  are protrusively provided on the same shaft center in its inside, whereby an adjustment opening  85  is formed between the protrusions  84 . 
     Then, while the engagement projection  82   a  is inserted through the engagement opening  76   b , both side edge portions of the upper side portion  52  of the movable iron piece  50  are held by one end portion of the card  80  and the pair of the protrusions  84 ,  84 , and the engagement pawl  53  of the movable iron piece  50  is engaged with the engagement recess  83  to prevent the card  80  from coming off. 
     The case  90  has a box shape capable of covering the base  10 . The case is assembled to the base  10  to which internal components are assembled, whereby an assembling work is completed. 
     Next, an operation method of the electromagnetic relay will be described. 
     That is, if a voltage is not applied to the coil  21  of the electromagnetic block  20 , the card  80  is urged to the movable iron piece  50  side by a spring force of the movable contact piece  76 . Therefore, the movable contact  77  is in contact with the normally-closed fixed contact  72 , and separated from the normally open fixed contact  74 . 
     Then, by applying a voltage to the coil  21  of the electromagnetic block  20 , the magnetic pole portion  31  of the iron core  30  attracts the movable iron piece  50 . Therefore, the movable iron piece  50  is rotated against the spring force of the movable contact piece  76 , whereby the card  80  is moved in a sliding manner in a horizontal direction to press the movable contact piece  76 , so that the movable contact  77  is separated from the fixed contact  72 , brought into contact with the fixed contact  74  and then the movable iron piece  50  is attracted to the magnetic pole portion  31 . 
     Then, if the voltage application to the coil  21  is stopped, the card  80  is pushed back by the spring force of the movable contact piece  76 , and the movable iron piece  50  is separated from the magnetic pole portion  31 . Thereafter, the movable contact  77  is separated from the fixed contact  74  and brought into contact with the fixed contact  72  to return to the original state. 
     If operation characteristics of the electromagnetic relay of the present embodiment are adjusted, as shown in  FIG. 6 , for example, a gauge portion  92  of a thickness gauge  91  having a thickness of 0.15 mm is inserted into the adjustment opening  85  formed between the pair of the protrusions  84 ,  84 . Then if a voltage is applied to the coil  21  to rotate the movable iron piece  50 , and the gauge portion  92  is held by the movable iron piece  50  and the magnetic pole portion  31  of the iron core  30 , whether or not the movable contact  77  is in contact with the normally open fixed contact  74  is judged by an electrical means. If they are not in contact with each other, since it means that a predetermined stroke with respect to the normally open fixed contact  74  is not obtained, the fixed contact terminal  73  and the like are slightly deformed to adjust the operation characteristics. 
     A second embodiment is a case where a press fitting protrusion  67  is provided by protruding work in place of the press-fitting elastic tongue piece provided at the horizontal portion  61  of the hinge spring  60  as shown in  FIG. 7 . According to the present embodiment, there is an advantage that the hinge spring  60  can be prevented from coming off without reducing its strength. Since the other portions are the same as those in the above embodiment, the same portions are designated by similar numerals and the description thereof is omitted. 
     A third embodiment is a case where the center of one end portion of the card  80  is provided with a slit  83   a  as shown in  FIG. 8 . According to the present embodiment, the one end side of the card  80  is easily elastically deformed, and the engagement pawl  53  is easily engaged, so that there is an advantage that assembling performance is improved. 
     INDUSTRIAL APPLICABILITY 
     The electromagnetic relay of the present invention can be applied not only to the above electromagnetic relays but also to other electromagnetic relays.