Patent Publication Number: US-2023145346-A1

Title: Component assemblies and methods of manufacturing component assemblies that include a magnetic yoke assembly for electromechanical contactors and relays

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 63/276,318, filed Nov. 5, 2021, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE TECHNOLOGY 
     The subject disclosure relates to component assemblies and methods of manufacturing component assemblies that include a magnetic yoke assembly for electromechanical contactors and relays. 
     BACKGROUND 
     Electromechanical switching devices, such as contactors and relays, are designed to carry certain amount of electrical current for certain periods of time. Existing designs struggle to perform during very high current, short duration events commonly called short-circuits, which can cause the internal electrical contacts to separate destructively (commonly called contact levitation). One solution to this problem involves the use of ferromagnetic components, known as yokes or armatures, configured around the electrical contacts such that the short-circuit current induces a magnetic field and an attractive “anti-levitation” force between the ferromagnetic components that prevents the electrical contacts from separating. Existing applications using this approach mount the yoke surrounding the moveable electrical contact onto the moving assembly, increasing the mass of the moving assembly. This reduces operation speed and negatively impacts contactor/relay switching performance. 
     SUMMARY 
     Component assemblies and methods of manufacturing component assemblies that include a magnetic yoke assembly for electromechanical contactors and relays are disclosed. In a particular embodiment, a component assembly that includes a magnetic yoke assembly for electromechanical contactors and relays is described. In this embodiment, the magnetic yoke assembly includes a movable contact and a ferromagnetic upper yoke mounted above the moveable contact and separate from the moveable contact. The magnetic yoke assembly also includes a ferromagnetic lower yoke mounted under the moveable contact. 
     In another embodiment, a method of manufacturing a component assembly that includes a magnetic yoke assembly for electromechanical contactors and relays is described. In this embodiment, the method includes mounting a ferromagnetic upper yoke above a moveable contact and separate from the moveable contact. The method also includes mounting a ferromagnetic lower yoke under the moveable contact. 
     As will be explained in further detail below, by mounting the magnetic yoke separately from a moveable contact in a magnetic yoke assembly, the mass of a moveable contact assembly is reduced, which improves the operational speed and performance of a component assembly over component assemblies that include previously known designs of magnetic yoke assemblies. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  2    is a diagram illustrating current flow within an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  3    is a diagram of various views of an example hermetic assembly of an electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  4    is a diagram of various views of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  5    is a diagram of an example Molex connector of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  6    is a diagram illustrating dimensions of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  7    is a diagram illustrating a view of an example external view of an arc envelope according to at least one embodiment of the present disclosure. 
         FIG.  8    is a chart of performance metrics for force on an actuator plunger based on a plunger position in the coil according to at least one embodiment of the present disclosure. 
         FIG.  9    is a diagram illustrating a view of a magnetic yoke assembly for electromechanical contactors and relays according to at least one embodiment of the present disclosure. 
         FIG.  10    is a diagram illustrating a view of a magnetic yoke assembly for electromechanical contactors and relays according to at least one embodiment of the present disclosure. 
         FIG.  11    is a diagram illustrating a view of a contact actuator of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  12    is a diagram illustrating a cross-sectional view of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  13    is a diagram illustrating a side cross-sectional view of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  14    is a diagram illustrating a front side cross-sectional view of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  15    is a diagram illustrating a chamfered yoke variation of a magnetic yoke assembly for electromechanical contactors and relays according to at least one embodiment of the present disclosure. 
         FIG.  16    is a cross-sectional view of an example electromechanical contactor with a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  17    is a graph of data from a short-circuit test using a chamfered yoke variation of a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  18    is a diagram illustrating a cross-sectional view of an electromechanical contactor that includes a chamfered yoke variation of a magnetic yoke assembly according to at least one embodiment of the present disclosure. 
         FIG.  19    is a diagram of a cage component of an electromechanical contactor that includes a magnetic yoke assembly with a chamfered yoke variation according to at least one embodiment of the present disclosure. 
         FIG.  20    is a flowchart of an example method of manufacture for a magnetic yoke assembly for electromechanical contactors and relays according to at least one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The terminology used herein for the purpose of describing particular examples is not intended to be limiting for further examples. Whenever a singular form such as “a”, “an” and “the” is used and using only a single element is neither explicitly or implicitly defined as being mandatory, further examples may also use plural elements to implement the same functionality. Likewise, when a functionality is subsequently described as being implemented using multiple elements, further examples may implement the same functionality using a single element or processing entity. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including”, when used, specify the presence of the stated features, integers, steps, operations, processes, acts, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, processes, acts, elements, components and/or any group thereof. 
     It will be understood that when an element is referred to as being “connected” or “coupled” to another element, the elements may be directly connected or coupled or via one or more intervening elements. If two elements A and B are combined using an “or”, this is to be understood to disclose all possible combinations, i.e., only A, only B, as well as A and B. An alternative wording for the same combinations is “at least one of A and B”. The same applies for combinations of more than two elements. 
     Accordingly, while further examples are capable of various modifications and alternative forms, some particular examples thereof are shown in the figures and will subsequently be described in detail. However, this detailed description does not limit further examples to the particular forms described. Further examples may cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. Like numbers refer to like or similar elements throughout the description of the figures, which may be implemented identically or in modified form when compared to one another while providing for the same or a similar functionality. 
     In a particular embodiment, the use of ferromagnetic components to improve short-circuit performance in contactors involves mounting a u-shaped ferromagnetic yoke that surrounds the moveable contact onto the moving assembly. 
     In a particular embodiment, the u-shaped yoke can also be chamfered to optimize the anti-levitation force. This allows further reduction of the lower yoke&#39;s mass. 
     According to embodiments of the present disclosure, a u-shaped ferromagnetic yoke is mounted above a moveable current-carrying contact, under which is a second ferromagnetic component. During a high current event (ex. short-circuits), the inverted yoke magnetically attracts the second ferromagnetic component under the moveable contact, increasing contact force and maintaining continuity. According to one or more embodiments of the present disclosure, the yoke is mounted separately from the moveable contact, thus reducing mass on the moving assembly, and thereby increasing mechanism operating speed in comparison to similar designs. In addition, mounting the yoke separately from the moveable contact allows for short-circuit performance improvement without the negative impact to switching performance. 
     In a particular embodiment, a magnetic yoke for improved switching performance in electromechanical contactors and relays includes bidirectional performance, improved corrosion resistance (CR) by removing plastic and coils from a sealed hermetic chamber. The yoke also includes modular performance—these requirements drive models used. Such requirements include make/break performance, levitation performance, isolated moveable, and aux normally open (NO) or normally closed (NC). The modular package includes housing, connectors, and mounting. 
     For further explanation,  FIG.  1    illustrates an example embodiment of an electromechanical contactor  100  according to at least one embodiment of the present disclosure. The contactor  100  includes an upper housing  102  and lower housing  106  that encloses the internal components of the contactor  100 , including the magnetic yoke assembly described in further detail below. The contactor  100  also includes a connector  104 . In some embodiments, the connector  104  includes a Molex connector  104  (see, e.g.,  FIG.  5   ). In other embodiments, the connector  104  includes solder pins, flying leads, or other types of connectors as can be appreciated. The contactor  100  also includes one or more terminals  108  for routing current through a moveable contact of a magnetic yoke assembly. 
     With respect to the bidirectional performance,  FIG.  2    illustrates that magnetic poles are in line with current direction, with non-sensitive installation. In the example of  FIG.  2   , arrows  202  show a magnetic pole direction. Arrows  204  show a direction of a flow of current. Arrows  206  shows an arc direction pending current flow.  FIG.  3    shows an example hermetic assembly  300 . In contrast to solutions for hermetic assemblies shown in the cross-sectional view  310 , plastic has been completely removed from the sealed chamber of the hermetic assembly  300  to reduce CR as shown in the cross-sectional view  320 . For isolated moveable and NC aux options, minimal plastic is used. In some implementations, the coil is removed from the hermetic chamber. This results in a chamber that is cleaner and has less moisture and contaminates. In this embodiment, changes in size/pin location do not impact the sealed design. 
     As is illustrated in the example contactor  402  of  FIG.  4   , no housing is required according to at least one embodiment of the present disclosure. In some embodiments, a one-up (see contactor  404 ) or two-up design (see contactor  406 ) is used. In some embodiments, the yoke is mounted with a space efficient, top-down install. In some embodiments, the housing can be modified to fit custom mounting schemes with changes to the dimensional envelope as shown in the example dimensions shown in  FIG.  6   .  FIG.  7    shows external views of an exterior view  702  of a contactor&#39;s arc envelope according to some embodiments of the present disclosure.  FIG.  8    shows a flow chart of performance metrics for the force on an actuator plunger based on a plunger position in the coil described herein according to various embodiments. 
       FIG.  9    shows the main components of an example yoke  900  according to some embodiments of the present disclosure. The yoke  900  includes a ferromagnetic upper yoke  902  and a ferromagnetic lower yoke  904 . The ferromagnetic upper yoke  902  is an upper u-shaped yoke while the ferromagnetic lower yoke  904  is a flat yoke. In some embodiments, the ferromagnetic lower yoke  904  includes an opening through which various components can pass. As an example, a plunger shaft of an actuator can pass through the opening. 
       FIG.  10    shows the yoke  900  mounted around a moveable contact  1002  according to some embodiments of the present disclosure. As shown in  FIG.  10   , the ferromagnetic upper yoke  902  and ferromagnetic lower yoke  904  wrap around movable contact  1002  to help prevent levitation. The moveable contact  1002  is in contact with terminals  1004 . In this example embodiment, arrow  1006  shows a direction of magnetic force, arrows  1008  show a direction of levitation force, and arrows  1010  show a direction of current flow. During a high current event, the ferromagnetic upper yoke  902  is drawn to the ferromagnetic lower yoke  904  by magnetic force. 
       FIG.  11    shows an example view of a contact actuator assembly with yokes included according to some embodiments of the present disclosure. As shown in  FIG.  11   , the ferromagnetic lower yoke  904  contacts the actuator  1102 . The ferromagnetic lower yoke  904  supports the moveable contact  1002  which is framed by the ferromagnetic upper yoke  902 . The actuator assembly  1102  includes a plunger shaft  1104  applied force by a plunger spring  1106 . In some embodiments, the plunger shaft  1104  passes through an opening in the ferromagnetic lower yoke  902 . In some embodiments, the plunger shaft  1104  passes through an opening in the moveable contact  1002 . Moreover, in some embodiments, when the plunger shaft  1104  is in an actuated state, the moveable contact  1002  conductively links the terminals  1004  to allow current to pass through the terminals  1004  via the moveable contact  1002 . 
       FIG.  12    shows a cross sectional view of a contactor  1200  with yoke design features according to some embodiments of the present disclosure. The contactor  1200  includes an actuator assembly including a plunger  1202  and plunger shaft  1104 . A plunger spring  1106  surrounds the plunger shaft  1104  and is housed in an inner chamber of the plunger  1202 . A standoff  1208  elevates the plunger shaft  1104 . 
     The plunger shaft  1104  passes through an opening in a moveable contact  1002 . The moveable contact  906  passes through a yoke including a ferromagnetic upper yoke  902  and a ferromagnetic lower yoke  904 . The yoke and actuator components are housed within an arc envelope  1210 , such as a ceramic arc envelope. A terminal  1004  extends from the top of the contactor  1200 . A lower portion of the contactor  1200  includes a coil bobbin  1212  housing the plunger  1202 . Coil wire  1214  surrounds the coil bobbin  1212 . The lower portion of the contactor  1200  is defined by a top core  1216  separator. 
       FIG.  13    shows an example contactor  1300  side cross-sectional view according to some embodiments of the present disclosure. As shown in the example side cross-sectional view, the contactor  1300  includes an arc envelope  1210  that supports the ferromagnetic upper yoke  902 . The ferromagnetic lower yoke  904  is attached to an actuator. The moveable contact  906  rests on the ferromagnetic lower yoke  904 . A plunger shaft  1104  passes through an opening in the moveable contact  1002 . 
       FIG.  14    shows an example contactor  1400  front cross-sectional view according to some embodiments of the present disclosure. As shown in  FIG.  14   , a plunger shaft  1104  passes through and is elevated by a standoff  1208 . The plunger shaft  1104  also passes through an opening in the ferromagnetic lower yoke  904  and the moveable contact  1002 . The ferromagnetic upper yoke  902  is supported by an arc envelope  1210 . Terminals  1004  contact the moveable contact  1002 , allowing for current to pass through the terminals  1004  via the moveable contact  1002 . 
       FIG.  15    shows a chamfered yoke  1500  variation according to some embodiments of the present disclosure. The chamfered yoke  1500  includes a chamfered upper yoke  1502  and a lower yoke  1504 . As shown, the lower yoke  1504  includes one or more openings to allow passage of other components, such as a plunger shaft  1104 . Both the chamfered upper yoke  1502  and the lower yoke  1504  are ferromagnetic as can be appreciated. 
       FIG.  16    shows a cross-sectional view of a contactor  1600  with a chamfered yoke  1500 . In the example contactor  1600 , the chamfered upper yoke  1502  is supported by an arc envelope  1602 . A moveable contact  1002  rests on the lower yoke  1504 . A plunger shaft  1104  passes through the openings in the lower yoke  1504  and the moveable contact  906 . The chamfered upper yoke  1502  allows additional ferromagnetic mass, increasing the anti-levitation force, without interfering with actuator movement.  FIG.  17    shows data from a 10 kA, 20 ms short-circuit test using a chamfered yoke design according to some embodiments of the present disclosure. Current is successfully passed through contactor using the chamfered yoke design. 
       FIG.  18    shows a design variation of a contactor  1800  including an over-molded component  1802  in the actuator that isolates the high-voltage current carry circuit from the low-voltage coil circuit according to some embodiments of the present disclosure. As shown, the over-molded component  1802  is coupled to a plunger shaft  1104  of an actuator. The ferromagnetic lower yoke  904  sits atop the over-molded component  1802 , with the moveable contact  1002  sitting on the ferromagnetic lower yoke  904 . The ferromagnetic upper yoke  902  and the ferromagnetic lower yoke  904  frame or encircle the moveable contact  1002 . 
       FIG.  19    shows a cage component  1902  used to attach the ferromagnetic upper yoke  902  to the arc envelope  1602  according to some embodiments of the present disclosure. The cage component  1902  is coupled to the arc envelope  1602  and holds the ferromagnetic upper yoke  902  in place. As shown, the arc envelope  1602  includes openings for terminals  1004  that can contact a moveable contact  1002  after assembly. 
       FIG.  20    shows a flowchart of an example method of manufacture for a contactor having a magnetic yoke for improved switching performance in electromechanical contactors and relays according to some embodiments of the present disclosure. The method of  FIG.  20    includes mounting  2002  a ferromagnetic upper yoke  902  in an inverted position above a moveable contact  1002  and separate from the moveable contact. In some embodiments, mounting  2002  the ferromagnetic upper yoke  902  includes supporting the ferromagnetic upper yoke  902  by an arc envelope  1602  such as a ceramic arc envelope  1602 . In some embodiments, mounting  2002  the ferromagnetic upper yoke  902  includes coupling or attaching the ferromagnetic upper yoke  902  to a cage component  1902  that is coupled to the arc envelope  1602 . The ferromagnetic upper yoke  902  is mounted above and separate from the moveable contact  1002  such that there is no direct physical coupling between the ferromagnetic upper yoke  902  and the moveable contact  1002 . 
     The method of  FIG.  20    also includes mounting  2004  a ferromagnetic lower yoke  904  under the moveable contact  1002 . Thus, the movable contact  1002  sits on or is attached to the ferromagnetic lower yoke  904 . In some embodiments, the ferromagnetic lower yoke  904  is attached or coupled to an actuator. In some embodiments, the ferromagnetic upper yoke  902  and ferromagnetic upper yoke  904  are mounted inside a chamber that is hermetically sealed. 
     It will be understood from the foregoing description that modifications and changes may be made in various embodiments of the present disclosure without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense. The scope of the present disclosure is limited only by the language of the following claims.