Patent Publication Number: US-9406469-B2

Title: Electromagnetic relay having a movable contact and a fixed contact and method for manufacturing the same

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to an electromagnetic relay, and especially to an electromagnetic relay capable of performing operation characteristics adjusting work for a fixed contact terminal. 
     2. Related Art 
     As a conventional electromagnetic relay, for example, there is an electromagnetic relay like one shown in FIG. 1 of Japanese Unexamined Patent Publication No. (Translation of PCT Application) No. 2001-521273, in which a core 16 is inserted from the lateral side through a coil tube 11 of a coil body 1 having first and second flanges 12, 13 at both ends thereof, while first and second fixed contact supports 3, 4 are assembled on the first flange 12 side from above. In the foregoing electromagnetic relay, a contact spring 23 rotates via an armature 22 that is adsorbed to and separated from the core 16, to open and close contacts. 
     SUMMARY 
     However, in the foregoing electromagnetic relay, it is necessary to plastically deform the upper ends of the first and second fixed contact supports 3, 4, for adjustment of operation characteristics which is performed in order to eliminate dispersion of component accuracy and assembly accuracy. This makes it troublesome to adjust the operation characteristics, causing low product yield as well as low productivity. 
     One or more embodiments of the present invention provides an electromagnetic relay, capable of easily adjusting operation characteristics and having high productivity and good yield, and a method for manufacturing the same. 
     An electromagnetic relay according to one or more embodiments of the present invention is an electromagnetic relay in which a movable touch piece is rotated by a movable iron piece configured to rotate based on magnetization and demagnetization of an electromagnet block, to make a movable contact that is provided on the movable touch piece come into contact with and separate from a fixed contact opposed to the movable contact. The electromagnetic relay has a configuration where operation characteristics are made adjustable by means of a press-fitting amount at the time of press-fitting a fixed contact terminal provided with the fixed contact into a spool of the electromagnet block along a moving direction of the movable contact. 
     According to one or more embodiments of the present invention, assembly work and operation characteristics adjusting work for the fixed contact terminal can be carried out by performing the same work, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. It is to be noted that the press-fitting amount means a pressing distance in the press-fitting. 
     According to one or more embodiments of the present invention, a configuration may be formed where the operation characteristics are made adjustable by means of a press-fitting amount at the time of press-fitting the fixed contact terminal, provided with the fixed contact located on the opposite side to the electromagnet block with respect to the movable contact, into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, the assembly work and the operation characteristics adjusting work for the fixed contact terminal can be carried out by performing the same work by press-fitting the fixed contact terminal, located on the opposite side to the electromagnet block, into the spool of the electromagnet block, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. 
     According to one or more embodiments of the present invention, a configuration may be formed where the operation characteristics are made adjustable by means of a press-fitting amount at the time of press-fitting the fixed contact terminal, provided with the fixed contact located on the opposite side to the electromagnet block out of a pair of fixed contacts opposed to each other with the movable contact provided therebetween, into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, the assembly work and the operation characteristics adjusting work for the fixed contact terminal can be carried out by performing the same work by press-fitting the fixed contact terminal into the spool of the electromagnet block, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. 
     Further, according to one or more embodiments of the present invention, a configuration may be formed where the operation characteristics are made adjustable, while alignment is made, by taking as a normally closed fixed contact the fixed contact located on the opposite side to the electromagnet block out of the pair of fixed contacts opposed to each other with the movable contact provided therebetween, and press-fitting a normally closed fixed contact terminal provided with the normally closed fixed contact into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, assembly work and operation characteristics adjusting work for the normally closed fixed contact terminal can be carried out by performing the same work by press-fitting the normally closed fixed contact terminal into the spool of the electromagnet block, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. 
     According to one or more embodiments of the present invention, a configuration may be formed where the operation characteristics are made adjustable by means of a press-fitting amount at the time of press-fitting the fixed contact terminal, provided with the fixed contact located on the electromagnet block side with respect to the movable contact, into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, the assembly work and the operation characteristics adjusting work for the fixed contact terminal can be carried out by performing the same work by press-fitting the fixed contact terminal into the spool of the electromagnet block, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. 
     Moreover, according to one or more embodiments of the present invention, a configuration may be formed where the operation characteristics are made adjustable, while alignment is made, by taking as a normally closed fixed contact the fixed contact located on the opposite side to the electromagnet block out of the pair of fixed contacts opposed to each other with the movable contact provided therebetween, and press-fitting a normally closed fixed contact terminal provided with the normally closed fixed contact into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, assembly work and operation characteristics adjusting work for the normally closed fixed contact terminal can be carried out by performing the same work by press-fitting the normally closed fixed contact terminal into the spool of the electromagnet block, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. 
     Furthermore, according to one or more embodiments of the present invention, a configuration may be formed where the operation characteristics are made adjustable, while alignment is made, by taking as a normally open fixed contact the fixed contact located on the electromagnet block side out of the pair of fixed contacts opposed to each other with the movable contact provided therebetween, and press-fitting a normally open fixed contact terminal provided with the normally closed fixed contact into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, assembly work and operation characteristics adjusting work for the normally open fixed contact terminal can be carried out by performing the same work by press-fitting the normally open fixed contact terminal into the spool of the electromagnet block, and hence it is possible to obtain an electromagnetic relay with high productivity and good yield. 
     According to one or more embodiments of the present invention, the fixed contact terminal may be arranged with the fixed contact between a pair of press-fitting portions that extend in parallel so as to be press-fitted into the spool of the electromagnet block. 
     According to one or more embodiments of the present invention, with the fixed contact accurately and firmly supported by the pair of press-fitting portions, it is possible to obtain an electromagnetic relay with high alignment accuracy and no dispersion of operation characteristics. 
     According to one or more embodiments of the present invention, the press-fitting portions may be respectively cut from corners formed by bending both-side edges of the fixed contact terminal in the same direction. 
     According to one or more embodiments of the present invention, the press-fitting portions may be cut from the corners formed by bending both-side edges of the fixed contact terminal. For this reason, not only the material yield is good, but also the fixed contact terminal has high rigidity and resists elastic deformation, and hence it is possible to obtain an electromagnetic relay having high supporting strength and alignment accuracy and no dispersion of operation characteristics. 
     A method for manufacturing an electromagnetic relay according to one or more embodiments of the present invention is a method for manufacturing an electromagnetic relay in which a movable touch piece is rotated by a movable iron piece configured to rotate based on magnetization and demagnetization of an electromagnet block, to make a movable contact that is provided on the movable touch piece come into contact with and separate from a fixed contact opposed to the movable contact. This method has a step where operation characteristics are adjusted by means of a press-fitting amount at the time of press-fitting a fixed contact terminal provided with the fixed contact into a spool of the electromagnet block along a moving direction of the movable contact. 
     According to one or more embodiments of the present invention, the assembly work and the operation characteristics adjusting work for the fixed contact terminal can be carried out by performing the same work by press-fitting the fixed contact terminal into the spool of the electromagnet block, and hence it is possible to obtain a method for manufacturing an electromagnetic relay with high productivity and good yield. 
     According to one or more embodiments of the present invention, there may be performed a step where the operation characteristics are adjusted by means of a press-fitting amount at the time of press-fitting the fixed contact terminal, provided with the fixed contact located on the opposite side to the electromagnet block with respect to the movable contact, into the spool of the electromagnet block along the moving direction of the movable contact. 
     Further, according to one or more embodiments of the present invention, there may be performed a step where the operation characteristics are adjusted by means of a press-fitting amount at the time of press-fitting the fixed contact terminal, provided with the fixed contact located on the electromagnet block side with respect to the movable contact, into the spool of the electromagnet block along the moving direction of the movable contact. 
     According to one or more embodiments of the present invention, the assembly work and the operation characteristics adjusting work for the fixed contact terminal can be carried out by performing the same work by press-fitting the fixed contact terminal into the spool of the electromagnet block, thus exerting the effect of being able to obtain a method for manufacturing an electromagnetic relay with high productivity and good yield. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are respectively a perspective view and a perspective view seen from a different angle, showing an electromagnetic relay according to one or more embodiments of the present invention; 
         FIG. 2  is an exploded perspective view of the electromagnetic relay shown in  FIG. 1A ; 
         FIG. 3  is an exploded perspective view of the electromagnetic relay shown in  FIG. 1B ; 
         FIGS. 4A and 4B  are respectively a longitudinal sectional view and a partial lateral sectional view of the electromagnetic relay shown in  FIG. 1 ; 
         FIGS. 5A and 5B  are longitudinal sectional views showing an assembled state of a casing shown in  FIG. 1 ; 
         FIGS. 6A and 6B  are longitudinal sectional views showing states before and after operation of the electromagnetic relay shown in  FIG. 1 ; 
         FIGS. 7A and 7B  are respectively a perspective view, and a perspective view seen from a different angle, of a base shown in  FIGS. 2 and 3 ; 
         FIGS. 8A and 8B  are respectively a perspective view, and a perspective view seen from a different angle, of a spool shown in  FIGS. 2 and 3 ; 
         FIG. 9  is a perspective view of a normally open fixed contact terminal and a normally closed fixed contact terminal shown in  FIGS. 2 and 3 ; and 
         FIGS. 10A and 10B  are respectively a bottom view and a longitudinal sectional perspective view of the casing shown in  FIGS. 2 and 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention will be described in accordance with the accompanying drawing of  FIGS. 1 to 10 . 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. As shown in  FIG. 2 , an electromagnetic relay according to the present embodiment is configured of a base  10 , a pair of electromagnet blocks  20  juxtaposed on the base  10 , a contact mechanism portion  40  assembled into the base  10  and the electromagnet block  20 , and a casing  60 . 
     As shown in  FIG. 7A , on the base  10 , a pair of aligning recessed portions  12 ,  12  is formed while a partition portion  11  projectingly provided in a central portion on the upper surface is placed therebetween. Further, at one-side edge out of mutually opposed both-side edges of the base  10 , a pair of notches  13 ,  13  to be fitted with a seal-retaining rib  23   b  of a spool  21 , which will be described later, are juxtaposed. Moreover, at the other-side edge of the base  10 , notches  14 ,  15  are alternately juxtaposed, the notches being to be fitted with a terminal portion  53  of a normally open fixed contact terminal  50  and a terminal portion  58  of a normally closed fixed contact terminal  55  which will be described later. Furthermore, as shown in  FIG. 7B , a continuous taper surface  16  is formed along an outer periphery of the rear surface of the base  10 . 
     As shown in  FIG. 2 , the electromagnet block  20  is formed such that a coil  30  is wound around a body  22  of a spool  21  while an iron core  31  having a substantially T-shape in section is inserted through a through hole  22   a  of the body  22 , and the projecting one end is made a magnetic pole portion  32  while the projecting other end  33  is caulked and fixed to a vertical portion  35  of a substantially L-shaped yoke  34 . A seal-retaining projected portion  35   a  is projectingly provided on the outward surface of the vertical portion  35 , and from the lower edge thereof, a movable contact terminal portion  36  provided with a chamfered portion  36   a  ( FIGS. 4, 5 ) extends to the lower side. 
     In particular, as shown in  FIG. 8 , the spool  21  has guard portions  23 ,  24  on both sides of the body  22 , and a recessed portion  23   a  to be fitted with the yoke  34  is formed on the outward surface of the one guard portion  23 , from the lower edge of which the seal-retaining rib  23   b  extends ( FIG. 8B ). Further, a press-fitting groove  23   c  where a coil terminal  37  can be press-fitted is provided on the side end surface of the guard portion  23  ( FIG. 4A ). Moreover, as shown in  FIG. 8A , press-fitting holes  24   a ,  24   b  are provided in upper and lower parts at each-side edge of the outward surface of the other guard portion  24  in the spool  21 . Furthermore, a seal-retaining rib  24   c  extends to the lateral side from a position adjacent to the press-fitting hole  24   a  at a side edge in the guard portion  24 . Then, engaging receiving portions  23   d ,  24   d  are respectively provided at upper corners of the opposed surfaces of the guard portions  23 ,  24 . 
     As shown in  FIG. 2 , the contact mechanism portion  40  is configured of a movable touch piece  41 , the normally open fixed contact terminal  50  and the normally closed fixed contact terminal  55 . 
     The movable touch piece  41  is made up of a conductive plate spring flexed in a substantially L-shape. One end thereof is provided with a movable contact  42 , while a vertical portion thereof is caulked and fixed to a movable iron piece  43 . Then, the other end of the movable touch piece  41  is caulked and fixed to a horizontal portion of the yoke  34 , thereby to rotatably support the movable iron piece  43  and the movable touch piece  41  around the leading edge of the horizontal portion of the yoke  34  as a fulcrum. 
     In the normally open fixed contact terminal  50 , as shown in  FIG. 9 , both-side edges located on both sides to a normally open fixed contact  51  having been caulked and fixed are flexed in parallel into a substantially C-shape in plain, and a press-fitting portion  52  is cut from the corner thereof, while a terminal portion  53  extends from the edge of one side thereof to the lower side. Press-fitting receiving portions  52   a  to come into press-contact with the press-fitting holes  24   a  of the spool  21  are provided in upper and lower parts in the press-fitting portion  52 , while a push-out preventive rib  52   b  for preventing push-out of chips from the press-fitting hole  24   a  is provided on a base of the press-fitting receiving portion  52   a . Further, a taper surface  52   c  for facilitating a press-fitting operation is formed on each side surface of the press-fitting portion  52 . 
     In the normally closed fixed contact terminal  55 , a pair of press-fitting portions  57  extends in parallel in a horizontal direction from the upper corners located to both sides of the normally closed fixed contact  56  having been caulked and fixed, and from the corner of the lower edge thereof, the terminal portion  58  extends to the lower side. Press-fitting receiving portions  57   a  to come into press-contact with the press-fitting holes  24   b  of the spool  21  are provided in upper and lower parts in the press-fitting portion  57 , while a push-out preventive rib  57   b  for preventing push-out of chips from the press-fitting hole  24   b  is provided on a base of the press-fitting receiving portion  57   a . Further, a taper surface  57   c  for facilitating a press-fitting operation is formed on each side surface of the press-fitting portion  57 . 
     As shown in  FIG. 2 , the casing  60  has a box shape fittable to the base  10  where the electromagnet block  20  and the contact mechanism portion  40  are assembled, and a corner portion of the upper surface thereof has a gas vent hole  61 . Further, as shown in  FIG. 10 , an insulating rib  62  is projectingly provided in a central portion on each of the opposed inner side surfaces of the casing  60 , while a position-regulating projected portion  63  is provided on the base of the insulating rib  62 . Moreover, position-regulating projected threads  64  as position-regulating projected portions are projectingly provided respectively at the opposed edges of the ceiling surface of the casing  60 . 
     Next, a procedure for assembling the foregoing constitutional components will be described. 
     First, the coil  30  is wound around the body  22  of the spool  21 , while a leader line thereof is bound to a binding portion  38  of the coil terminal  37  press-fitted into the press-fitting groove  23   c  of the guard portion  23  and soldered, and thereafter the binding portion  38  is bent inward. Then, the iron core  31  is inserted through the through hole  22   a  provided in the body  22  of the spool  21 , and the projecting other end is caulked and fixed to the vertical portion  35  of the yoke  34 , to complete the electromagnet block  20 . Subsequently, the other end of the movable touch piece  41  caulked and fixed with the movable iron piece  43  is caulked and fixed to the horizontal portion of the yoke  34 . Further, the press-fitting portion  52  of the normally open fixed contact terminal  50  is press-fitted into the press-fitting hole  24   a , provided at the edge of the outward surface of the guard portion  24  of the electromagnet block  20 , along the shaft center of the iron core  31 , to contactably and separably arrange the movable contact  42  on the normally open fixed contact  51 . At this time, a contact distance between the normally open fixed contact  51  of the normally open fixed contact terminal  50  and the movable contact  42  can be adjusted by means of a press-fitting amount of the press-fitting portion  52 , thereby to allow adjustment of the operation characteristics such as an operating voltage and a restoration voltage. 
     Subsequently, the electromagnet blocks  20 ,  20  are respectively aligned in the pair of aligning recessed portions  12 ,  12  of the base  10  such that the shaft center of the iron core  31  is in parallel with the upper surface of the base  10 . Then, the seal-retaining rib  23   b  of the spool  21  is fitted to the notch  13  of the base  10  while the terminal portions  53 ,  58  of the normally open fixed contact terminal  50  and the normally closed fixed contact terminal  55  are fitted to the notches  14 ,  15  ( FIGS. 1, 4 ). 
     Moreover, the press-fitting portion  57  of the normally closed fixed contact terminal  55  is press-fitted into the press-fitting hole  24   b  of the guard portion  24  along the shaft center of the iron core  31 . A contact distance between the normally closed fixed contact  56  of the normally closed fixed contact terminal  55  and the movable contact  42  can be adjusted by means of a press-fitting amount of the press-fitting portion  57  at this time, thereby to allow adjustment of the operation characteristics such as an operating voltage and a restoration voltage. 
     According to the present embodiment, the operation characteristics can be accurately adjusted while the press-fitting portion  57  of the normally closed fixed contact terminal  55  is press-fitted into the press-fitting hole  24   b  of the spool  21 , thereby to facilitate an assembly operation and an adjustment operation, leading to improvement in productivity and yield. For this reason, internal constitutional components are not required to have high dimensional accuracy, thereby to facilitate manufacturing of the internal constitutional components. It is to be noted that the internal constitutional components refer to components constituting the electromagnet block, such as the coil wound around the spool, the iron core and the yoke, and components constituting the contact mechanism portion such as the movable touch piece and the fixed touch piece. 
     Further, since the press-fitting portions  52 ,  57  can be press-fitted into the press-fitting holes  24   a ,  24   b  arranged in upper and lower parts along each-side edge of the guard portion  24 , it is possible to save spaces to install the normally open fixed contact terminal  50  and the normally closed fixed contact terminal  55 , so as to obtain an electromagnetic relay with a small floor area, especially a small lateral width. 
     It is to be noted that, although the configuration has been formed in the present embodiment where the contacts are arranged in the order of the normally open fixed contact  51 , the movable contact  42  and the normally closed fixed contact  56  from the side close to the electromagnet block  20  (cf.  FIG. 6 ), the order of the normally open fixed contact and the normally closed fixed contact can be changed, or either one fixed contact may be omitted. 
     Then, by fitting the casing  60  to the base  10 , the pair of electromagnet blocks  20 ,  20  is partitioned by the insulating rib  62  ( FIG. 4B ), the position-regulating projected portion  63  and the position-regulating projected thread  64 , provided in the casing  60 , are fitted to the engaging receiving portions  23   d ,  24   d  of the guard portions  23 ,  24 , to regulate the positions ( FIG. 5 ). 
     According to the present embodiment, it is possible to accurately align the electromagnet blocks  20 ,  20  in predetermined positions on the base  10 , so as to obtain an electromagnetic relay with little dispersion of operation characteristics. 
     Further, according to the present embodiment, as shown in  FIG. 5B , the engaging receiving portions  23   d ,  24   d  are left-right asymmetric, which is a structure capable of preventing wrong assembly. 
     It is to be noted that, although the case has been described in the present embodiment where a total of four engaging receiving portions  23   d ,  24   d  are provided in the guard portions  23 ,  24 , at least one engaging receiving portion may be provided, and two or three may be provided. Especially in the case of providing two engaging receiving portions, it is preferable to arrange those on a diagonal line. However, the present invention is not limited to such a configuration. 
     Finally, a sealing member is injected and solidified to be sealed via the taper surface  16  provided along the peripheral edge of the bottom surface of the base  10  shown in  FIG. 1B . 
     According to the present embodiment, a space between the base  10  and the casing  60  is blocked by the seal-retaining ribs  23   b ,  24   c  provided in the guard portions  23 ,  24 . Further, the seal-retaining projected portion  35   a  provided on the outward surface of the yoke  34  is in contact with the inner side surface of the casing  60 . Hence it is possible to prevent the sealing member from getting into the casing  60 , and prevent the sealing member from adhering to the internal constitutional component such as the movable touch piece  41 . 
     Next, the operation of the electromagnetic relay according to the present embodiment will be described. 
     That is, as shown in  FIG. 6A , prior to application of a voltage to the coil  30  of the electromagnet block  20 , the movable contact  42  is in contact with the normally closed fixed contact  56  due to spring force of the movable touch piece  41 . 
     Then, by applying a voltage to the coil  30  to magnetize it, the movable iron piece  43  is sucked to the magnetic pole portion  32  of the iron core  31  to rotate against the spring force of the movable touch piece  41 . Therefore, after the contacts are opened as the movable contact  42  is separated from the normally closed fixed contact  56  and it then comes into contact with the normally open fixed contact  51 , the movable iron piece  43  is adsorbed to the magnetic pole portion  32  of the iron core  31  ( FIG. 6B ). 
     Subsequently, when the magnetization of the coil  30  is released (demagnetization), the contacts are opened as the movable contact  42  is separated from the normally open fixed contact  51  due to the spring force of the movable touch piece  41 , and the movable iron piece  43  rotates in a reverse direction while the movable contact  42  comes into contact with the normally closed fixed contact  56 , to restore the original state. 
     Although the electromagnetic relay including the normally open fixed contact terminal and the normally closed fixed contact terminal has been described in the foregoing embodiment, it may be applied to an electromagnetic relay having either one of the normally open fixed contact terminal and the normally closed fixed contact terminal. 
     Further, it may not be restricted to the case of providing a pair of electromagnet blocks, but may be applied to the case of providing one electromagnet block. 
     Moreover, it may naturally be applied to an electromagnetic relay where the shaft center of the electromagnet block is arranged so as to be orthogonal to the upper surface of the base. 
     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.