Abstract:
A high voltage relay device according to the present invention includes fixed contacts, a movable contact provided at one side of the fixed contacts and contactable with or separated from the fixed contacts, fixed-side arc electrodes coupled to the fixed contacts, and a movable-side arc electrode coupled to one side of the movable contact and contactable with or separated from the fixed-side arc electrodes when the movable contact is brought into contact with or separated from the fixed contacts, whereby a generation of arc from primary electrodes when current flows and is cut off can be prevented so as to enhance reliability of the primary electrodes, and also usage of specialized materials may result in reduction of material costs.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     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. 10-2015-0109086, filed on Jul. 31, 2015, the contents of which are all hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This specification relates to a high voltage relay device, and more particularly, a high voltage relay device having arc electrodes in addition to primary electrodes. 
     2. Background of the Invention 
     Hybrid electric vehicles (HEVs) and fuel cell electric vehicles (FCEVs), which replace currently-used diesel or gasoline vehicles, are expected to be key issues in the development of vehicle engines, in the aspects of running out of oil riches and eco-friendly environment. 
     The HEV uses the existing engine and a battery as power sources. At an initial operation, the HEV is accelerated by using electric energy produced using battery power, and recharging/discharging of the battery is repeatedly performed using an engine and a brake according to a driving speed. The HEV exhibits higher fuel efficiency when a percentage of using the battery as a power source is higher. Accordingly, it is expected that a capacity of the battery is gradually increasing according to consumers&#39; demands. In order to increase the capacity of the battery, the most convenient way is to increase a voltage. So, usage voltages of recently-produced batteries have increased from 12V, which is a conventionally used voltage level, to 200˜300 V, and in future, a further increase is expected. This requires for high insulating capabilities of peripheral electric devices. Accordingly, a high voltage relay which functions to power on/off a high voltage battery is newly developed now and high reliability of the high voltage relay is also required. 
       FIG. 1  is a longitudinal sectional view illustrating a high voltage relay for an electric vehicle according to the related art. 
     As illustrated in  FIG. 1 , a high voltage relay for an electric vehicle according to the related art includes a fixed electrode  1  having a fixed contact  11 , a movable contact arm  20  having a movable contact  21  which is contactable with or separated from the fixed contact  11 , an arc-extinguishing unit  3  for extinguishing arc A that is generated upon a contact or separation between the fixed electrode  1  and the movable contact arm  20 , and a driving unit  4  for driving the movable contact arm  2 . 
     The fixed electrode  1  is provided as a pair each having the fixed contact  11  on its end portion. 
     The movable contact arm  2  is formed in the shape of a flat plate, and provided with the movable contact  21  at a surface facing the fixed contacts  11 . 
     The arc-extinguishing unit  3  includes a case  31  forming an arc-extinguishing space of the arc A using an insulating material, and a permanent magnet (not illustrated) for controlling the arc A generated between the fixed electrodes  1  and the movable contact arm  2 . The case  31  is formed of an insulating material, for example, ceramic, and the pair of fixed electrodes  1  is coupled to an upper portion of the case  31 . The movable contact arm  2  is installed within the case  31  in a manner of being simultaneously brought into contact with or spaced apart from the fixed contacts  11 , and a downwardly-extending connection shaft  46  is coupled to a center of the movable contact arm  2 . 
     The driving unit  4  includes a bobbin  41  in a cylindrical shape, an excitation coil  42  wound around a circumference of the bobbin  41 , a yoke  43  disposed below the case  31 , a fixed core  44  disposed within the bobbin  41 , a movable core  45  brought into contact with or separated from the fixed core  44 , a connection shaft  46  having one end connected to the movable contact arm  2  and another end connected to the movable core  45  through the fixed core  44 , and a return spring  47  applying an elastic force to the movable core  45  to be separated from the fixed core  44 . 
     The high voltage relay for the electric vehicle according to the related art will operate in the following manner. 
     That is, when power is applied to the excitation coil  42 , the excitation coil  42  generates an electronic attractive force. The movable core  45  is then moved upward until being brought into contact with the fixed core  44 , due to the electronic attractive force. The movable contact arm  2  connected to the movable core  45  by the connection shaft  46  is moved upward, in response to the upward movement of the movable core  45 , such that the movable contact  21  of the movable contact arm  2  is brought into contact with the fixed contacts  11 . Accordingly, a primary circuit which has been open may be closed. 
     On the other hand, when power supplied to the excitation coil  42  is cut off, the electronic attractive force is not generated from the excitation coil  42  any more. Accordingly, the return spring  47  which is interposed between the fixed core  44  and the movable core  45  returns to its original state. During this, the movable core  45  is pushed down. The movable contact arm  2  is also moved down along with the movable core  45 , such that the movable contact  21  is separated from the fixed contacts  11 . Consequently, the primary circuit is shorted or open. 
     In this instance, while the fixed contacts  11  and the movable contact  21  are brought into contact with or separated from each other, the arc A is always generated between the fixed contacts  11  and the movable contact  21 . As such, both conduction and arc extinguishment are caused between the fixed contacts  11  and the movable contact  21 , and thus the fixed contacts  11  and the movable contact  21  should be formed of a material which simultaneously satisfies electric conductivity and resistance to arc, in view of ensuring reliability. However, the two properties are difficult to be simultaneously satisfied due to a characteristic of a material, and a material satisfying them is very expensive and difficult to be processed. 
     SUMMARY OF THE INVENTION 
     Therefore, an aspect of the detailed description is to provide a high voltage relay device, which has an improved contact structure by separately employing electrodes managing conduction of the relay and electrodes managing arc extinguishment, respectively, and which is relatively cheap and easily processed while satisfying both of electric conductivity and durability by using materials which are specialized for the electric conductivity and the durability, respectively. 
     To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a high voltage relay device, including fixed contacts, a movable contact provided at one side of the fixed contacts and contactable with or separated from the fixed contacts, fixed-side arc electrodes coupled to the fixed contacts, and a movable-side arc electrode coupled to one side of the movable contact and contactable with or separated from the fixed-side arc electrodes when the movable contact is brought into contact with or separated from the fixed contacts. 
     Here, the fixed-side arc electrodes and the movable-side arc electrode may be brought into contact with each other before the fixed contacts and the movable contact are brought into contact with each other and separated from each other after the fixed contacts and the movable contact are separated from each other. 
     The least interval between the fixed-side arc electrodes and the movable-side arc electrode may be shorter than the least interval between the fixed contacts and the movable contact. 
     An inner circumferential surface of the movable-side arc electrode may be brought into contact with outer circumferential surfaces of the fixed-side arc electrodes in a sliding manner. 
     The fixed-side arc electrodes and the movable-side arc electrode may be made of a material with heat resistance or abrasion resistance superior to that of a material forming the fixed contacts and the movable contact. 
     The fixed contacts and the movable contact may be made of a material with conductivity superior to that of a material forming the fixed-side arc electrodes and the movable-side arc electrode. 
     To achieve these and other advantages of the present invention, there is provided a high voltage relay device, including fixed electrodes each having a fixed contact, a movable contact arm having a movable contact that performs a relative motion with respect to the fixed contacts of the fixed electrodes to be contactable with or separated from the fixed contacts, an arc-extinguishing unit provided to accommodate the fixed electrodes and the movable contact arm and capable of extinguishing arc generated when the fixed contacts and the movable contact are brought into contact with or separated from each other, a driving unit capable of driving the movable contact arm, fixed-side arc electrodes coupled to the fixed electrodes, and a movable-side arc electrode coupled to the movable contact arm and contactable with or separated from the fixed-side arc electrodes so as to configure a part of the arc-extinguishing unit. 
     Here, a stepped surface may be formed on at least one of an outer circumferential surface of each of the fixed electrodes and an outer circumferential surface of the movable contact arm, and each of the fixed-side arc electrodes or the movable-side arc electrode may be coupled to the stepped surface in an inserting manner. 
     The least interval between the fixed-side arc electrodes and the movable-side arc electrode may be shorter than the least interval between the fixed contacts and the movable contact, and an inner diameter of the movable-side arc electrode may be greater than an outer diameter of each of the fixed-side arc electrodes, such that an inner circumferential surface of the movable-side arc electrode and an outer circumferential surface of each of the fixed-side arc electrodes are brought into contact with each other in an overlapping manner. 
     Guide surfaces each in an inclined or curved shape may be formed at a lower edge of the outer circumferential surface of each of the fixed-side arc electrodes and an upper edge of the inner circumferential surface of the movable-side arc electrode, respectively. 
     The fixed-side arc electrodes and the movable-side arc electrode may be formed in a cylindrical shape. 
     At least one of each of the fixed-side arc electrodes and the movable-side arc electrode may be coupled to only a part of an outer circumferential surface of the corresponding fixed electrode or movable contact arm. 
     The high voltage relay device according to the present invention may employ arc electrodes managing arc extinguishment, in addition to primary electrodes managing conduction, and the primary electrodes and the arc electrodes may be made of materials with electric conductivity and resistance to arc, respectively. This may prevent a generation of arc from the primary electrodes when current flows or is cut off, thereby enhancing reliability of the primary electrodes. Also, the usage of such specialized materials may result in reduction of material costs. 
     Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description. 
    
    
     
       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 exemplary embodiments and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a longitudinal sectional view illustrating a high voltage relay for an electric vehicle according to the related art; 
         FIG. 2  is a longitudinal sectional view illustrating one embodiment of a high voltage relay for an electric vehicle in accordance with the present invention; 
         FIG. 3  is a longitudinal sectional view illustrating relationship between a contact and an arc electrode of  FIG. 2 ; 
         FIG. 4  is a longitudinal sectional view illustrating another embodiment related to fixed-side arc electrodes and movable-side arc electrodes according to  FIG. 2 ; 
         FIGS. 5 and 6  are longitudinal sectional views illustrating relationship between contacts and arc electrodes during a current-flowing (conductive) state and a current-cutoff (broken) state according to  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given in detail of a high voltage relay device according to the present invention, with reference to the accompanying drawings. 
       FIG. 2  is a longitudinal sectional view illustrating one embodiment of a high voltage relay device for a vehicle in accordance with the present invention,  FIG. 3  is a longitudinal sectional view illustrating relationship between a contact and an arc electrode of  FIG. 2 , and  FIG. 4  is a longitudinal sectional view illustrating another embodiment related to fixed-side arc electrodes and movable-side arc electrodes according to  FIG. 2 . 
     As illustrated, the high voltage relay device for the electric vehicle according to this exemplary embodiment may include an arc-extinguishing unit  130  accommodating therein fixed contacts  111  and a movable contact  121 , and extinguishing arc generated when the fixed contacts  111  and the movable contact  121  are brought into contact with or separated from each other, a driving unit  140  provided at one side of the arc-extinguishing unit  130  and allowing the movable contact  121  to move, a sealing unit  150  sealing a space or a gap between the arc-extinguishing unit  130  and the driving unit  140 , and an arc interrupting unit  160  disposed between the arc-extinguishing unit  130  and the driving unit  140  within the sealing unit  150  and preventing a leakage of the arc A into the sealing unit  150 . 
     The arc-extinguishing unit  130  may include a case  131  made of an insulating material and forming an inner space for extinguishing the arc, and a permanent magnet (not illustrated) controlling the arc A generated between the fixed contacts  111  and the movable contact  121 . The case  131  may be formed of an insulating material, such as ceramic, and a plurality of fixed electrodes  110  each having a fixed contact  111  may be coupled to an upper portion of the case  131 . 
     A movable contact arm  120  having the movable contact  121  which is simultaneously brought into contact with or separated from the fixed contacts  111  may be installed within the case  131 , and a connection shaft  146  which downwardly extends to be connected to the driving unit  140  may be coupled to a center of the movable contact arm  120 . The connection shaft  146  will be explained later. 
     The driving unit  140  may include a bobbin  141  in a cylindrical shape, an excitation coil  142  wound on a circumference of the bobbin  141 , a yoke  143  disposed below the case  131 , a fixed core  144  disposed at an inner side of the bobbin  141 , a movable core  145  brought into contact with and separated from the fixed core  144 , a connection shaft  146  having one end connected to the movable contact  121  and another end connected to the movable core  145  through the fixed core  145 , and a return spring  147  applying an elastic force to the movable core  145  to be separated from the fixed core  144 . 
     The sealing unit  150  may be provided with a seal cup  151  which is made of a metal material and seals the inner space between the arc-extinguishing unit  130  and the driving unit  140  so as to prevent a leakage of gas within such inner space. The seal cup  151  may be formed in a shape of a round cup. An upper end of the seal cup  151  may be closely adhered onto a lower surface of the case  131  of the arc-extinguishing unit  130  and a lower end thereof may be closely adhered onto an upper surface of the yoke  143  of the driving unit  140 . 
     The arc-interrupting unit  160  may include a plate  161  formed in approximately the same shape as an open surface of the case  131  of the arc-extinguishing unit  130 , and a sealing protrusion  162  protruding from an upper surface of the plate  161  toward the case  131  by a predetermined height so as to be slidably inserted into an inner circumferential surface of the case  131 . 
     The high voltage relay device for the electric vehicle according to this embodiment will operate in the following manner. 
     That is, when power is applied to the excitation coil  142  of the driving unit  140 , the movable core  145  may be moved in a direction of being contactable with the fixed core  144 . The connection shaft  146  integrally coupled to the fixed core  144  may be moved accordingly and the movable contact  121  may be brought into contact with the fixed contacts  111 , thereby allowing a flow of current. 
     On the other hand, when power supplied to the excitation coil  142  is cut off, the movable core  144  may be separated from the fixed core  144  by an elastic force of the return spring  147 , and simultaneously the movable contact  121  may be separated from the fixed contacts  111 . 
     In this instance, arc A in a streamline shape may be generated between the fixed contacts  111  and the movable contact  121 . Here, since the case  131  is formed of the insulating material, this arc A may be locked in the inner space of the case  131  and apt to be induced to the seal cup  151  made of the metal material. However, the arc A may be prevented from being induced to the seal cup  151  by the arc-interrupting unit  160  which surrounds the inner circumferential surface of the seal cup  151 , namely, the open surface of the case  131 . 
     Meanwhile, according to this embodiment, as illustrated in  FIGS. 2 and 3 , arc electrodes  181  and  182  which serve to extinguish arc may be provided at circumferences of the fixed contacts  111  and the movable contact  121 , respectively. In this instance, the fixed contacts  111  and the movable contact  121  may manage conduction (flow of current), and the arc electrodes  181  and  182  may manage arc extinguishment. Accordingly, the fixed contacts  111  and the movable contact  121  may be made of a material facilitating the conduction, and the arc electrodes  181  and  182  may be made of a material facilitating the arc extinguishment. 
     For example, the fixed contacts  111  and the movable contact  121  may be made of copper or copper alloy that a material such as molybdenum or zirconium is contained in copper, taking into account conductivity or heat resistance. On the other hand, the arc electrodes  181  and  182  may be made of copper alloy that a material, such as tungsten, which has relatively higher intensity than the material forming the fixed contacts  111  or the movable contact  121 , is contained in copper, taking into account abrasion resistance or heat resistance. 
     The arc electrodes  181  and  182  should be brought into contact with the fixed contacts  111  before the movable contact  121  is brought into contact with the fixed contacts  111  and should be separated from the fixed contacts  111  after the movable contact  121  is separated from the fixed contacts  111 . Consequently, the arc electrodes  181  and  182  may preferably be formed to protrude higher than a cross section of the fixed contacts  111  or the movable contact  121 . That is, as illustrated in  FIG. 3 , the least interval t 1  between the fixed-side arc electrode and the movable-side arc electrode may be shorter than the least interval t 2  between the fixed contacts  111  and the movable contact  121 . 
     To this end, the arc electrodes may include a plurality of fixed-side arc electrodes  181  coupled to the fixed electrodes  110 , and a movable-side arc electrode  182  coupled to the movable contact arm  120 . The fixed-side arc electrode  182  coupled to the movable contact arm  120 . The fixed-side arc electrodes  181  and the movable-side arc electrode  182  may be brought into contact with or separated from each other in a sliding manner. Here, the fixed-side arc electrodes  181  and the movable-side arc electrode  182  may be coupled in a press-fitting, welding or bolting manner. 
     Since the fixed-side arc electrodes  181  and the movable-side arc electrode  182  are brought into contact with or separated from each other in the sliding manner, the fixed-side arc electrodes  181  and the movable-side arc electrode  182  should be supported in a sliding direction to maintain reliability. For this, each of the fixed-side arc electrodes  181  and the movable-side arc electrode  182  may be formed in a cylindrical shape, and stepped surfaces  112  and  122 , to which the fixed-side arc electrodes  182  and the movable-side arc electrode  182  are coupled in an inserting manner, respectively, may be formed at an outer circumferential surface of the fixed electrode  110  and an outer circumferential surface of the movable contact arm  120 , respectively. 
     An outer diameter of each of the fixed-side arc electrodes  181  may be the same as or slightly smaller than an inner diameter of the movable-side arc electrode  182 . Accordingly, guide surfaces  181   a  and  182   a  each of which is formed as a tilt surface or a curved surface may be formed in a facing manner at an upper edge of an inner circumferential surface of the movable-side arc electrode  182  and a lower edge of an outer circumferential surface of each fixed-side arc electrode  181 , so as to guide the inner circumferential surface of the movable-side arc electrode  182  to be inserted into the outer circumferential surface of the fixed-side arc electrode  181 . 
     Alternatively, the fixed-side arc electrode  181  may not be formed in a cylindrical shape. For example, as illustrated in  FIG. 4 , both of the fixed-side arc electrodes  181  may come in contact at an almost one point with the inner circumferential surface of the movable-side arc electrode  182 . Accordingly, the fixed-side arc electrodes  181  and the movable-side arc electrode  182  may be formed only at portions where the fixed-side arc electrodes  182  and the movable-side arc electrode  182  come in contact with each other. In this instance, the fixed-side arc electrodes  182  or the movable-side arc electrode  182  may preferably be fixed in a welding manner or by a separate coupling member  185 , such as a bolt. Of course, one of the fixed-side arc electrode and the movable-side arc electrode may be formed in a cylindrical shape so as to be press-fit into a corresponding contact, and only the other may be formed in a non-cylindrical shape so as to be fixed by a coupling member. 
     Hereinafter, operation effects of the high voltage relay device for the electric vehicle having such arc electrodes according to the embodiment will be described. 
     As illustrated in  FIG. 5 , when the movable contact arm  120  is moved toward the fixed electrodes  110 , the movable contact  121  may be brought into contact with the fixed contacts  111 , thereby allowing a flow of current. During this, arc may be generated between the fixed contacts  111  and the movable contact  121 . However, the fixed-side arc electrodes  181  may be installed at the fixed electrodes  110  and the movable-side arc electrode  182  may be installed at the movable contact arm  120 . Accordingly, the fixed-side arc electrodes  181  and the movable-side arc electrode  182  may be brought into contact with each other before the fixed contacts  111  and the movable contact  121  are brought into contact with each other. 
     That is, the fixed-side arc electrodes  181  and the movable-side arc electrode  182  are in contact with each other and the interval t 1  between the two arc electrodes  181  and  182  becomes zero (0) accordingly, but the fixed contacts  111  and the movable contact  121  may still be spaced apart from each other by the predetermined interval t 2 . 
     Accordingly, arc may be generated between the fixed-side arc electrodes  181  and the movable-side arc electrode  182 , thereby preventing the generation of the arc between the fixed contacts  111  and the movable contact  121  having relatively low resistance to arc. 
     Here, the fixed-side arc electrodes  181  and the movable-side arc electrode  182  may be formed of a material with resistance to arc, and thus general durability of the high voltage relay device can be improved more than a relay in which the arc is generated between the fixed contacts and the movable contact. 
     On the other hand, as illustrated in  FIG. 6 , when the movable contact arm  120  is moved away from the fixed electrodes  110 , the movable contact  121  may be separated from the fixed contacts  111 , thereby blocking a flow of current. In this instance, the fixed contacts  111  and the movable contact  121  are already spaced by the predetermined interval (t 2 ≠0), but the fixed-side arc electrodes  181  and the movable-side arc electrode  182  may still be in a contact state by the predetermined height h. 
     Accordingly, as the fixed-side arc electrodes  181  and the movable-side arc electrode  182  are separated from each other later than the fixed contacts  111  and the movable contact  121 , the arc may be generated between the fixed-side arc electrodes  181  and the movable-side arc electrode  182  which have relatively high resistance to arc. This may prevent the generation of the arc between the fixed contacts  111  and the movable contact  121 , thereby improving durability of the high voltage relay device.