Abstract:
The present invention relates to a magnetic switch, and more particularly, to a magnetic switch provided with a permanent magnet disposed at an outside of an upper frame and an externally fitted permanent magnet holder to reduce a number of components and facilitate maintenance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Patent Application No. 10-2015-0051883, filed on Apr. 13, 2015, the contents of which are hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a magnetic switch, and more particularly, to a magnetic switch provided with a permanent magnet disposed at an outside of an upper frame and an externally fitted permanent magnet holder to reduce a number of components and facilitate maintenance. 
     2. Description of the Related Art 
     In general, as a type of electrical circuit switching device for transferring mechanical drives and current signals using the principle of an electromagnet, a magnetic switch or direct current relay is installed in various facilities, machines, vehicles and the like. 
     In particular, in case of a relay for electric vehicles, it may be located at a battery system in an electric vehicle such as a hybrid vehicle, a fuel cell vehicle, a golf cart and an electric forklift to perform the role of switching the conductivity of a main current. 
     A direct current relay for electric vehicles may include a high voltage portion and a low voltage portion. The high voltage (HV) portion is connected to an electric wire or bus bar to take charge of the conduction and blocking of a main current, and the low voltage (LV) portion operates a drive unit to turn on or off the direct current relay. In general, a direct current relay for electric vehicles is located within a battery system. 
       FIG. 1  illustrates a lateral longitudinal cross-sectional view of a magnetic switch according to the related art, and  FIG. 2  illustrates an internal perspective view of an upper frame assembly in  FIG. 1 . 
     The configuration of a direct current relay for electric vehicles may include a lower frame  1 , an upper frame  2 , a pair of fixed contacts  3  and movable contacts  4  installed within the upper frame  2 , and an electric actuator  5  installed within the lower frame  1  to drive the movable contacts  4  to allow the switching control of contacts due to an electrical signal. A permanent magnet  6   a ,  6   b  is fixed to a permanent magnet holder  7  and provided within the upper frame  2  to effectively control an arc occurring during the blocking of contacts. 
     The operation during the blocking will be described with reference to  FIG. 3 . A pair of fixed contacts  3  ( 3   a ,  3   b ) are configured with two main contact terminals to have a positive (+) and a negative (−) polarity. A permanent magnet  6   a ,  6 B installed within the upper frame  2  forms a magnetic field (B), and fixed to a permanent magnet holder (not shown) to provide the path of a magnetic field. A magnetic field (B) generated from the permanent magnet  6   a ,  6   b  interacts with a current (+I, −I) to generate a force (+F, −F) of pushing an arc occurring during the switching to an outside, thereby performing the role of reducing the damage of a contact portion. 
     However, a magnetic switch according to the related art is assembled in such a manner that two permanent magnet holders  7  are pushed and installed into the upper frame  2  in a symmetric manner, and then permanent magnets  6   a ,  6   b  are coupled to both end portions of two permanent magnet holders  7 , respectively. The reason of providing two permanent magnet holders  7  is that the operation of pushing and installing into the upper frame  2  is difficult with one integrated form of permanent magnet holder  7 . In other words, there is a drawback of increasing the number of components and deteriorating the work process. 
     Furthermore, two permanent magnet holders  7  are pushed and installed into the upper frame  2 , which is a plastic injection molded part, thereby causing a problem of suppressing the intrinsic function of permanent magnets  6   a ,  6   b  in case where the permanent magnet holders  7  are released therefrom. 
     Moreover, it is assembled such a manner that the permanent magnets  6   a ,  6   b  are fixed to the permanent magnet holders  7  and the permanent magnet holders  7  are pushed and installed into the upper frame  2 , thereby deteriorating the disassembly performance and causing a damage on the surrounding parts during the process of performing dismantling operation when the permanent magnets  6   a ,  6   b  are removed for maintenance or the like. 
     SUMMARY OF THE INVENTION 
     The present invention is contrived to solve the foregoing problems, and an aspect of the present invention is to provide a magnetic switch provided with a permanent magnet disposed at an outside of an upper frame and an externally fitted permanent magnet holder so as to reduce a number of components and facilitate maintenance. 
     A magnetic switch according to an embodiment of the present disclosure may include an upper frame formed in a box shape on which a lower surface thereof is open; a pair of fixed contacts installed in a fixed manner within the upper frame; a movable contact brought into contact with or separated from the pair of fixed contacts to conduct or block a circuit; a pair of permanent magnets disposed on part of the upper frame; and a permanent magnet holder coupled to part of the upper frame to fix the pair of permanent magnets to the upper frame, wherein a first and a second mounting portion are provided at outer sides on a front and a rear surface of the upper frame, respectively, to place the pair of permanent magnets into the first and the second mounting portion, and the permanent magnet holder is formed in a U-shape and coupled to an upper portion of the upper frame to fix the pair of permanent magnets to an outside of the upper frame. 
     Here, the first and the second mounting portion may have a groove formed with a width and area capable of accommodating the permanent magnet. 
     Furthermore, a holder insertion portion into which the permanent magnet holder can be fixed may be formed on an upper surface of the upper frame. 
     Furthermore, the holder insertion portion may include a groove portion formed between a pair of protrusion portions protruded in an “11” shape. 
     Furthermore, part of the holder insertion portion may be protruded from a front surface of the upper frame to form a support portion. 
     Furthermore, the permanent magnet holder may include a body portion formed to transverse an upper surface of the upper frame and bridge portions extended in a vertically downward direction at both end portions of the body portion. 
     Furthermore, engagement portions engaged with lower end portions of the first and the second mounting portion, respectively, may be formed in a bent manner at both end portions of the permanent magnet holder. 
     Furthermore, adhesion portions capable of applying a contact pressure to the permanent magnets, respectively, may be formed at both end portions of the permanent magnet holder. 
     In addition, a handle portion may be provided on part of the permanent magnet holder. 
     According to a magnetic switch according to an embodiment of the present disclosure, a permanent magnet may be coupled to an outside of the upper frame by a permanent magnet holder, thereby having an effect of facilitating the assembly and removal work. Furthermore, it may reduce possibility of damaging the surrounding components during the removal. 
     On the other hand, the permanent magnet holder may be configured with a single component, thereby implementing the simplification of components and reducing the manufacturing cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a lateral longitudinal cross-sectional view illustrating a magnetic switch according to the related art; 
         FIG. 2  is an internal perspective view illustrating an upper frame assembly in  FIG. 1 ; 
         FIG. 3  is a configuration diagram illustrating an interactive relationship between a contact portion and a permanent magnet during the blocking in a magnetic switch according to the related art; 
         FIG. 4  is a perspective view illustrating a magnetic switch according to an embodiment of the present disclosure, in a state that a case is removed therefrom; 
         FIG. 5  is an exploded perspective view illustrating an upper frame assembly in  FIG. 4 ; 
         FIG. 6  is a rear perspective view illustrating an upper frame in  FIG. 4 ; 
         FIG. 7  is a perspective view illustrating a permanent magnet holder according to another embodiment of the present disclosure; and 
         FIGS. 8, 9 and 10  are perspective views illustrating a permanent magnet holder according to still another embodiment of the present disclosure, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings to such an extent that the present invention can be easily implemented by a person having ordinary skill in the art to which the present invention pertains, but it does not mean that the technical concept and scope of the present invention are limited due to this. 
       FIG. 4  illustrates a perspective view of a magnetic switch according to an embodiment of the present disclosure, and  FIG. 5  illustrates an exploded perspective view of an upper frame assembly, and  FIG. 6  illustrates a rear perspective view of an upper frame. A magnetic switch according to each embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. 
     A magnetic switch according to an embodiment of the present disclosure may include an upper frame  10  formed in a box shape on which a lower surface thereof is open; a pair of fixed contacts  20  installed in a fixed manner within the upper frame  10 ; a movable contact  25  brought into contact with or separated from the pair of fixed contacts  20  to conduct or block a circuit; a pair of permanent magnets  30  disposed on part of the upper frame  10 ; and a permanent magnet holder  40  coupled to part of the upper frame  10  to fix the pair of permanent magnets  30  to the upper frame  10 , wherein a first and a second mounting portion  11 ,  12  are provided at outer sides on a front and a rear surface of the upper frame  10 , respectively, to place the pair of permanent magnets  30  into the first and the second mounting portion  11 ,  12 , and the permanent magnet holder  40  is formed in a U-shape and coupled to an upper portion of the upper frame  10  to fix the pair of permanent magnets  30  to an outside of the upper frame  10 . 
     The upper frame  10  may be formed in a box shape on which a lower surface thereof is open. The upper frame  10  may be formed of a synthetic resin material such as plastic. The upper frame  10  may be formed of an injection molded part. 
     A support surface  14  extended to a front and a rear side may be formed at a lower portion of the upper frame  10 . A plurality of fixed protrusions  14   a  capable of fixing the upper frame  10  to a plate  23  for connecting the upper frame  10  to a lower frame  17  may be formed in a protruding manner on the support surface  14 . 
     A pair of contact holes  13  on which the fixed contacts  20  can be installed are formed on an upper surface of the upper frame  10 . 
     A pair of insertion grooves  16  into which a terminal  15  or bus bar connected to the fixed contact  20  can be inserted are formed on a front surface of the upper frame  10 . The positions of the insertion grooves may correspond to the positions of the fixed contacts  20 , respectively. Here, the terminal  15  may be formed of a material such as silver (Ag) or the like having a good conductivity. Furthermore, a through hole  15   a  into which the fixed contact  20  can be inserted and installed is formed on part of the terminal  15 . 
     A first mounting portion  11  on which a permanent magnet  30  can be mounted is formed on a front surface of the upper frame  10 . The first mounting portion  11  may be formed in a protruding manner in a substantially U shape at a lower portion of the upper frame  10  in consideration of a place at which the insertion grooves  16  is formed. The first mounting portion  11  has a width and area capable of accommodating the permanent magnet  30 . 
     A second mounting portion  12  on which a permanent magnet  30  can be mounted is formed on a rear surface of the upper frame  10 . The second mounting portion  12  may be formed in a protruding manner in a substantially “□” shape. An inner portion of the second mounting portion  12  has a width and area capable of accommodating the permanent magnet  30 . 
     A holder insertion portion  18  into which a permanent magnet holder  40  can be inserted and fixed may be formed at a central portion on an upper surface of the upper frame  10 . The holder insertion portion  18  may be configured with a groove portion  18   b  between a pair of protrusion portions  18   a  protruded in an “11” shape. Part of the holder insertion portion  18  may be protruded to a front surface of the upper frame  10  to form a support portion  18   c . The support portion  18   c  along with the first mounting portion  11  supports the permanent magnet  30 . 
     The lower frame  17  is coupled to a lower portion of the plate  23 , and a coil assembly  19  and an actuator (not shown) may be installed therewithin. 
     A pair of fixed contacts  20  are terminals that can be inserted into the through holes  15   a  of the terminals  15  and the contact holes  13  of the upper frame  10  to be exposed to an outside of the upper frame  10 , and connected to a power source or load. A pair of fixed contacts  20  may be formed of a material such as copper (Cu) or the like having a good conductivity. An upper end portion of the pair of fixed contacts  20  may be connected to a power source or load, and a lower end portion thereof may be brought into contact with the moving contact  25 . A connecting groove  21  may be formed on an upper end portion of the pair of fixed contacts  20  to insert a contact terminal of load thereinto. 
     The fixed contacts  20  are inserted into the through holes  15   a  of the terminals  15  and the contact holes  13  of the upper frame  10  from the bottom to the top direction in a state that the terminals  15  are inserted into the insertion grooves  16  of the upper frame  10 , and coupled thereto in a manner of being pressed and riveted at an upper portion in a state of being fixed and supported by a jig or the like. 
     The movable contact  25  is a terminal inserted into the upper frame  10  and brought into contact with and separated from a pair of fixed contacts  20 . The movable contact  25  is brought into contact with a lower end portion of the foregoing pair of fixed contacts  20 . The movable contact  25  is a plate-shaped body having a predetermined thickness on which a surface facing the fixed contact  20  is formed in a flat shape. The movable contact  25  may be fixed to a drive shaft (not shown) installed within the coil assembly  19 , and brought into contact with or separated from a pair of fixed contacts  20  as the drive shaft is linearly driven along an axial direction. A circuit is closed to allow conduction when the movable contact  25  is brought into contact with a pair of fixed contacts  20 , and the circuit is open to block the flow of a current when the movable contact  25  is separated from a pair of fixed contacts  20 . 
     A pair of permanent magnets  30  are installed on the upper frame  10 . The pair of permanent magnets  30  may be installed on the first mounting portion  11  and second mounting portion  12 , respectively. Here, the position of the permanent magnet  30  corresponds to a position at which the fixed contact  20  is brought into contact with the movable contact  25  based on the height. At this time, the pair of permanent magnets  30  may be installed such that surfaces having the same polarity direct the same direction. For example, they may be installed such that the S-pole (N-pole) is directed to the front. In this manner, a magnetic field directed from the rear to the front (or directed from the front to the rear) may be formed within the upper frame  10 . In general, they are installed such that an arc generated during the blocking due to an interaction between the magnetic field and a current flowing through a pair of fixed contacts  20  in an upward or downward direction, respectively, receives a force of being pushed to an outer side. 
     The permanent magnet holder  40  may be formed in a substantially U-shape. The permanent magnet holder  40  may be made of a steel. 
     The permanent magnet holder  40  may include a body portion  41  formed to transverse an upper surface of the upper frame  10  and bridge portions  42  extended in a vertically downward direction at both end portions of the body portion  41 . 
     A distance between both the bridge portions  42  may be set to a distance that can be engaged in a fitting manner to provide a contact pressure capable of fixing a pair of permanent magnets  30  thereto in a state that that the permanent magnets  30  are coupled to the first mounting portion  11  and second mounting portion  12 , respectively. 
     The body portion  41  may be inserted and fixed into the holder insertion portion  18  of the upper frame  10 . The body portion  41  is fixed to the holder insertion portion  18  in a state that a pair of permanent magnets  30  are placed on the first and the second mounting portion  11 ,  12 , respectively, and both the bridge portions  42  support the pair of permanent magnets  30 , and thus the pair of permanent magnets  30  are stably coupled to the upper frame  10 . 
     A pair of permanent magnets  30  may be placed on an outside of the upper frame  10 , and the permanent magnet holder  40  may be coupled thereto with a simple fitting operation without the help of a jig or the like, thereby having an effect of simplifying the work process and reducing the manufacturing time compared to the related art in which they are installed within the upper frame. Furthermore, a complicated disassembly work due to tools is not required as in the related art since the disassembly work is completed by simply separating the permanent magnet holder  40  therefrom even during the disassembly work for maintenance, thereby having an effect of simplifying the work process and reducing the manufacturing time. Furthermore, according to the related art, there is a possibility of deteriorating the disassembly work of permanent magnets and damaging the surrounding components during the process of using a tool or the like, but a magnetic switch according to an embodiment of the present disclosure has an effect of significantly reducing the possibility of damage. 
       FIG. 7  illustrates a perspective view of a permanent magnet holder according to another embodiment of the present disclosure. According to the present embodiment, the permanent magnet holder  140  is formed such that an engagement portion  43  is bent in an inward direction at a lower end of the bridge portion  42 . The permanent magnet  30  is more stably fixed by the engagement portion  43  engaged with a lower portion of the first and the second mounting portion  12  to prevent the permanent magnet  30  from being released during use. 
       FIG. 8  illustrates a perspective view of a permanent magnet holder according to still another embodiment of the present disclosure. According to the present embodiment, an adhesion portion  44  is formed at a lower end of the bridge portion  42  of the permanent magnet holder  240 . The width of the adhesion portion  44  is formed to be larger than that of the bridge portion  42  to increase a contact area to the permanent magnet  30 . Accordingly, it has an effect of increasing a force supporting the permanent magnet  30 . According to the embodiment, a contact pressure portion  45  formed in a protruding manner may be provided at an inner side of the adhesion portion  44  to further increase a contact pressure force to the permanent magnet  30 . 
       FIGS. 9 and 10  illustrate perspective views of a permanent magnet holder according to still yet another embodiment of the present disclosure. According to the present embodiment, a permanent magnet holder  340 ,  440  may include a handle portion  46 ,  47  formed on part of the body portion  41 . The handle portion  46 ,  47  allows an effect of more easily performing a release operation when releasing the permanent magnet holder  340 ,  440 . 
     According to a magnetic switch according to an embodiment of the present disclosure, a permanent magnet may be coupled to an outside of the upper frame by a permanent magnet holder, thereby having an effect of facilitating the assembly and removal work. Furthermore, it may reduce possibility of damaging the surrounding components during the removal. 
     On the other hand, the permanent magnet holder may be configured with a single component, thereby implementing the simplification of components and reducing the manufacturing cost. 
     It will be apparent to those skilled in this art that various changes and modifications may be made thereto without departing from the gist of the present invention. Accordingly, it should be noted that the embodiments disclosed in the present invention are only illustrative and not limitative to the concept of the present invention, and the scope of the concept of the invention is not limited by those embodiments. The scope protected by the present invention should be construed by the accompanying claims, and all the concept within the equivalent scope of the invention should be construed to be included in the scope of the right of the present invention.