Patent Publication Number: US-2023143466-A1

Title: Magnetic component and magnetic body thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a magnetic component and a magnetic body thereof and, more particularly, to a magnetic component and a magnetic body thereof capable of uniformizing magnetic field distribution and improving thermal balance. 
     2. Description of the Related Art 
     A magnetic component is an important electric component used for storing energy, converting energy and isolating electricity. In most of circuits, there is always a magnetic component installed therein. In general, the magnetic component mainly comprises a reactor, a transformer and an inductor. The magnetic component usually consists of a magnetic body and at least one coil disposed in the magnetic body. When an electronic device equipped with the magnetic component is operating, heat generated by the magnetic component will be accumulated to make the temperature of the electronic device rise, such that the operating efficiency of the electronic device will be reduced or even the magnetic body may crack. Therefore, how to avoid heat accumulation to improve thermal balance for the magnetic component has become a significant design issue. 
     SUMMARY OF THE INVENTION 
     The invention provides a magnetic component and a magnetic body thereof capable of uniformizing magnetic field distribution and improving thermal balance, so as to solve the aforesaid problems. 
     According to an embodiment of the invention, a magnetic component comprises a magnetic body and a coil. The magnetic body comprises an inner leg, at least one outer leg, a first bottom portion and a second bottom portion. The inner leg and the at least one outer leg protrude from the first bottom portion and the second bottom portion. A cross-sectional area of the inner leg is larger than a total cross-sectional area of the at least one outer leg. The coil is wound around the inner leg. 
     According to another embodiment of the invention, a magnetic body comprises an inner leg, at least one outer leg and a bottom portion. A cross-sectional area of the inner leg is larger than a total cross-sectional area of the at least one outer leg. The inner leg and the at least one outer leg protrude from the bottom portion. 
     As mentioned in the above, the invention adjusts and optimizes the cross-sectional areas of the inner leg and the at least one outer leg of the magnetic body to improve the characteristics of the magnetic component. Specifically, the cross-sectional area of the inner leg is larger than the total cross-sectional area of the at least one outer leg. When the structure of the magnetic body conforms to the aforesaid geometric criteria, the magnetic body can uniformize magnetic field distribution and then avoid heat accumulation to improve thermal balance for the magnetic component. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view illustrating a magnetic component according to an embodiment of the invention. 
         FIG.  2    is a perspective view illustrating a core shown in  FIG.  1   . 
         FIG.  3    is a top view illustrating the core shown in  FIG.  2   . 
         FIG.  4    is a side view illustrating the magnetic component shown in  FIG.  1   . 
         FIG.  5    is a front view illustrating the core shown in  FIG.  2   . 
         FIG.  6 A  is a perspective view illustrating a range of a volume of an inner leg shown in  FIG.  5   . 
         FIG.  6 B  is a perspective view illustrating the ranges of volumes of a first bottom portion and a second bottom portion shown in  FIG.  5   . 
         FIG.  6 C  is a perspective view illustrating the ranges of volumes of two outer legs shown in  FIG.  5   . 
         FIG.  7    is a perspective view illustrating a magnetic body according to another embodiment of the invention. 
         FIG.  8    is a perspective view illustrating a magnetic body according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS.  1  to  6 C ,  FIG.  1    is a cross-sectional view illustrating a magnetic component  1  according to an embodiment of the invention,  FIG.  2    is a perspective view illustrating a core  10   a  shown in  FIG.  1   ,  FIG.  3    is a top view illustrating the core  10   a  shown in  FIG.  2   ,  FIG.  4    is a side view illustrating the magnetic component  1  shown in  FIG.  1   ,  FIG.  5    is a front view illustrating the core  10   a  shown in  FIG.  2   ,  FIG.  6 A  is a perspective view illustrating a range of a volume V 1  of an inner leg  100  shown in  FIG.  5   ,  FIG.  6 B  is a perspective view illustrating the ranges of volumes V 2 _ 1 , V 2 _ 2  of a first bottom portion  104  and a second bottom portion  106  shown in  FIG.  5   , and  FIG.  6 C  is a perspective view illustrating the ranges of volumes V 3 _ 1 , V 3 _ 2  of two outer legs  102  shown in  FIG.  5   . 
     The magnetic component  1  of the invention may be a reactor, a transformer, an inductor or other magnetic components. As shown in  FIG.  1   , the magnetic component  1  comprises a magnetic body  10  and a coil  12 . The magnetic body  10  comprises an inner leg  100 , at least one outer leg  102 , a first bottom portion  104  and a second bottom portion  106 . Preferably, the first bottom portion  104  and the second bottom portion  106  may be plate structures and the magnetic body  10  may be a symmetric structure. The magnetic body  10  may be formed in one-piece or consists of a plurality of cores. In this embodiment, the magnetic body  10  may consist of two E cores  10   a ,  10   b , but the invention is not so limited. The number and type of the cores of the magnetic body  10  may be determined according to practical applications. For example, the core of the magnetic body  10  may be E core, EFD core, EPC core, PQ core, EC core, low profile core, POT core, ETD core, EP core, RM core, solid center post RM core, and so on. In this embodiment, the cores  10   a ,  10   b  have identical structure and  FIGS.  2  and  3    only show the core  10   a  for illustration purpose. However, in another embodiment, the cores  10   a ,  10   b  may have different structures. 
     In this embodiment, the magnetic body  10  may comprise a plurality of outer legs  102 , but the invention is not so limited. As shown in  FIG.  1   , the magnetic body  10  comprises two outer legs  102  and the inner leg  100  is disposed between the two outer legs  102 , wherein the inner leg  100  and the two outer legs  102  protrude from the first bottom portion  104  and the second bottom portion  106 . In this embodiment, the core  10   a  comprises a part of the inner leg  100 , parts of the two outer legs  102  and the first bottom portion  104 , and the core  10   b  comprises a part of the inner leg  100 , parts of the two outer legs  102  and the second bottom portion  106 . However, in another embodiment, the cores  10   a ,  10   b  may also have one single outer leg  102  according to practical applications. 
     In this embodiment, the coil  12  is wound around the inner leg  100  and there is no coil wound around the outer leg  102 . A magnetic flux MF generated by the coil  12  wound around the inner leg  100  passes through cross-sectional areas of the inner leg  100 , the first bottom portion  104 , the outer leg  102  and the second bottom portion  106  in sequence. Furthermore, a gap may exist between the inner legs  100  or/and the outer legs  102  of the cores  10   a ,  10   b  according to practical applications. 
     In this embodiment, a cross-sectional area of the inner leg  100  is larger than a total cross-sectional area of the outer leg  102 . As shown in  FIG.  3   , the cross-sectional area of the inner leg  100  is defined as A 1 , and the cross-sectional areas of the two outer legs  102  are defined as A 3 _ 1 , A 3 _ 2 . Thus, the cross-sectional areas of the inner leg  100  and the two outer legs  102  conform to the following inequality: A 1 &gt;A 3 _ 1 +A 3 _ 2 . It should be noted that the aforesaid inequality (A 1 &gt;A 3 _ 1 +A 3 _ 2 ) is adapted to the magnetic body  10  with two outer legs  102 . When the structure of the magnetic body  10  conforms to the aforesaid geometric criteria, the magnetic body  10  can uniformize magnetic field distribution and then avoid heat accumulation to improve thermal balance for the magnetic component  1 . 
     It should be noted that the number of the at least one outer leg  102  may be equal to N (N is a positive integer) and the cross-sectional areas of the inner leg  100  and the cross-sectional areas of the N outer legs  102  may be defined as A 3 _ 1 , . . . , A 3 _N. Thus, the N outer legs  102  conform to the following inequality: A 1 &gt;A 3 _ 1 + . . . +A 3 _N. In another embodiment, if the number of the at least one outer leg  102  is equal to 1, the cross-sectional areas of the inner leg  100  and the outer leg  102  conform to the following inequality: A 1 &gt;A 3 _ 1 . In another embodiment, if the number of the at least one outer leg  102  is equal to 4, the cross-sectional areas of the inner leg  100  and the four outer legs  102  conform to the following inequality: A 1 &gt;A 3 _ 1 +A 3 _ 2 +A 3 _ 3 +A 3 _ 4 . 
     In this embodiment, the cross-sectional area of the inner leg  100  is larger than the total cross-sectional area of the two outer legs  102 . Preferably, from the viewing angle shown in  FIG.  3   , a length-to-width ratio L 1 /W 1  of the inner leg  100  is between 1 and 10, and a length-to-width ratio L 2 /W 2  of the outer leg  102  is between 1 and 10. In another embodiment, the length-to-width ratio L 1 /W 1  of the inner leg  100  may be between 1 and 8, and the length-to-width ratio L 2 /W 2  of the outer leg  102  may be between 1 and 8. In this embodiment, a height of the magnetic body  10  may be between 22 mm and 152 mm (i.e. the height of each of the two cores  10   a ,  10   b  may be between 11 mm and 76 mm). Accordingly, the effect of the invention may be more outstanding. 
     In another embodiment, the cross-sectional area of the inner leg  100  may be further larger than an effective cross-sectional area of the magnetic body  10 . When a number of the at least one outer leg  102  is equal to N (N is a positive integer), the effective cross-sectional area of the magnetic body  10  may be obtained by Aeff=(A 1 *V 1 +A 2 _ 1 *V 2 _ 1 +A 2 _ 2 *V 2 _ 2 +A 3 _ 1 *V 3 _ 1 + . . . +A 3 _N*V 3 _N)/((V 1 *N+V 2 _ 1 +V 2 _ 2 +V 3 _ 1 + . . . +V 3 _N)/N), wherein Aeff represents the effective cross-sectional area, A 1  represents the cross-sectional area of the inner leg  100  (as shown in  FIG.  3   ), A 2 _ 1  represents a cross-sectional area of the first bottom portion  104  (as shown in  FIG.  4   ), A 2 _ 2  represents a cross-sectional area of the second bottom portion  106  (as shown in  FIG.  4   ), A 3 _N represents a cross-sectional area of an N-th outer leg of the N outer legs  102  (as shown in  FIG.  3   ), V 1  represents a volume of the inner leg  100  (as shown in  FIGS.  5  and  6 A ), V 2 _ 1  represents a volume of the first bottom portion  104  (as shown in  FIGS.  5  and  6 B ), V 2 _ 2  represents a volume of the second bottom portion  106  (as shown in  FIGS.  5  and  6 B ), and V 3 _N represents a volume of the N-th outer leg of the N outer legs  102  (as shown in  FIGS.  5  and  6 C ). In this embodiment, the number of the at least one outer leg  102  is equal to 2 (i.e. N=2), so Aeff=(A 1 *V 1 +A 2 _ 1 *V 2 _ 1 +A 2 _ 2 *V 2 _ 2 +A 3 _ 1 *V 3 _ 1 +A 3 _ 2 *V 3 _ 2 )/((V 1 *2+V 2 _ 1 +V 2 _ 2 +V 3 _ 1 +V 3 _ 2 )/2). In another embodiment, if the number of the at least one outer leg  102  is equal to 1 (i.e. N=1), Aeff=(A 1 *V 1 +A 2 _ 1 *V 2 _ 1 +A 2 _ 2 *V 2 _ 2 +A 3 _ 1 *V 3 _ 1 )/((V 1 *1+V 2 _ 1 +V 2 _ 2 +V 3 _ 1 )/1). In another embodiment, if the number of the at least one outer leg  102  is equal to 4 (i.e. N=4), Aeff=(A 1 *V 1 +A 2 _ 1 *V 2 _ 1 +A 2 _ 2 *V 2 _ 2 +A 3 _ 1 *V 3 _ 1 +A 3 _ 2 *V 3 _ 2 +A 3 _ 3 *V 3 _ 3 +A 3 _ 4 *V 3 _ 4 )/((V 1 * 4 +V 2 _ 1 +V 2 _ 2 +V 3 _ 1 +V 3 _ 2 +V 3 _ 3 +V 3 _ 4 )/4). 
     In this embodiment, for example, provided that A 1  is equal to 530 mm 2 , A 2 _ 1  is equal to 262 mm 2 , A 2 _ 2  is equal to 220 mm 2 , A 3 _ 1  is equal to 260 mm 2 , A 3 _ 2  is equal to 220 mm 2 , V 1  is equal to 14861 mm 3 , V 2 _ 1  is equal to 6064 mm 3 , V 2 _ 2  is equal to 5091.9 mm 3 , V 3 _ 1  is equal to 4974 mm 3 , and V 3 _ 2  is equal to 4208.8 mm 3 , Aeff will be equal to 511.56 mm 2  through the aforesaid equation. When the structure of the magnetic body  10  further conforms to the aforesaid geometric criteria, the magnetic body  10  can also uniformize magnetic field distribution and then avoid heat accumulation to improve thermal balance for the magnetic component  1 . In the aforesaid inequality and equation, when A 2 _ 1  is equal to A 2 _ 2  or/and A 3 _ 1  is equal to A 3 _ 2 , the thermal stress will be further reduced. 
     In another embodiment, the cross-sectional area of the inner leg  100  may be further larger than a total cross-sectional area of the first bottom portion  104  and the second bottom portion  106 . As shown in  FIG.  3   , the cross-sectional area of the inner leg  100  is defined as A 1 . As shown in  FIG.  4   , the cross-sectional area of the first bottom portion  104  is defined as A 2 _ 1  and the cross-sectional area of the second bottom portion  106  is defined as A 2 _ 2 . Thus, the cross-sectional areas of the inner leg  100 , the first bottom portion  104  and the second bottom portion  106  conform to the following inequality: A 1 &gt;A 2 _ 1 +A 2 _ 2 . It should be noted that the cross-sectional area of the inner leg  100  may also be equal to the total cross-sectional area of the first bottom portion  104  and the second bottom portion  106  (i.e. A 1 =A 2 _ 1 +A 2 _ 2 ), but it is preferred to use A 1 &gt;A 2 _ 1 +A 2 _ 2 . Furthermore, if the first bottom portion  104  and the second bottom portion  106  have identical cross-sectional area, the cross-sectional area of the inner leg  100  will be larger than two times the cross-sectional area of the first bottom portion  104  or the second bottom portion  106  (i.e. A 1 &gt;2*A 2 _ 1  or A 1 &gt;2*A 2 _ 2 ). When the structure of the magnetic body  10  conforms to the aforesaid geometric criteria, the magnetic body  10  can uniformize magnetic field distribution and then avoid heat accumulation to improve thermal balance for the magnetic component  1 . 
     Referring to tables 1 and 2 below, tables 1 and 2 show several effect comparisons between the original structure and the improved structure of the invention. In table 2, AB represents differential magnetic distribution and ΔT represents differential temperature, wherein AB is the difference between the magnetic field density B 1  of the inner leg  100  and the magnetic field density B 3  of the outer leg  102 . As shown in tables 1 and 2, it is obvious that the invention can uniformize magnetic field distribution and then avoid heat accumulation to improve thermal balance for the magnetic component  1  indeed. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Aeff 
                 A1 
                 A2_1 
                 A2_2 
                 A3_1 
                 A3_2 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Example 1 
                 Original 
                 540 
                 508 
                 288 
                 288 
                 254 
                 254 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 509 
                 508 
                 285 
                 285 
                 160 
                 160 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                 Example 2 
                 Original 
                 535 
                 457 
                 305 
                 305 
                 261.5 
                 261.6 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 553 
                 542 
                 312 
                 312 
                 223 
                 223 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                 Example 3 
                 Original 
                 540 
                 510 
                 280 
                 280 
                 260 
                 260 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 526 
                 530 
                 262 
                 262 
                 260 
                 260 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                 Example 4 
                 Original 
                 527 
                 457 
                 288 
                 288 
                 262 
                 262 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 545 
                 542 
                 255 
                 255 
                 291 
                 291 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                 Example 5 
                 Original 
                 527 
                 457 
                 288 
                 288 
                 262 
                 262 
               
               
                   
                 structure 
                   
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 531 
                 542 
                 289 
                 289 
                 223 
                 223 
               
               
                   
                 structure 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                   
                   
                   
                   
                 After 10 
                   
               
               
                   
                   
                 A1/ 
                 A1/ 
                 minutes 
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 (A2_1 + 
                 (A3_1 + 
                 ΔB= 
                   
                 Geometric 
               
               
                   
                   
                 A2_2) 
                 A3_2) 
                 B1 − B3 
                 ΔT 
                 criteria 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Example 1 
                 Original 
                 0.88 
                 1.00 
                 42.5 
                 8 
                 A1 = (A3_1 + 
               
               
                   
                 structure 
                   
                   
                   
                   
                 A3_2) 
               
               
                   
                 Improved 
                 0.89 
                 1.59 
                 −28.2 
                 1 
                 A1 &gt; (A3_1 + 
               
               
                   
                 structure 
                   
                   
                   
                   
                 A3_2) 
               
               
                   
                   
                   
                   
                   
                   
                 A1≈Aeff 
               
               
                   
                   
                   
                   
                   
                   
                 B1 &lt; B3 
               
               
                 Example 2 
                 Original 
                 0.75 
                 0.87 
                 14 
                 36 
                   
               
               
                   
                 structure 
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 0.87 
                 1.22 
                 −13.45 
                 15 
                 A1 &gt; (A3_1 + 
               
               
                   
                 structure 
                   
                   
                   
                   
                 A3_2) 
               
               
                   
                   
                   
                   
                   
                   
                 B1 &lt; B3 
               
               
                 Example 3 
                 Original 
                 0.91 
                 0.98 
                 42.5 
                 110 
                   
               
               
                   
                 structure 
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 1.01 
                 1.02 
                 34.55 
                 70 
                 A1 &gt; (A2_1 + 
               
               
                   
                 structure 
                   
                   
                   
                   
                 A2_2) 
               
               
                   
                   
                   
                   
                   
                   
                 A1 &gt; (A3_1 + 
               
               
                   
                   
                   
                   
                   
                   
                 A3_2) 
               
               
                   
                   
                   
                   
                   
                   
                 A1 &gt; Aeff 
               
               
                 Example 4 
                 Original 
                 0.79 
                 0.87 
                 14 
                 36 
                   
               
               
                   
                 structure 
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 1.06 
                 0.93 
                 6.6 
                 20 
                 A1 &gt; (A2_1 + 
               
               
                   
                 structure 
                   
                   
                   
                   
                 A2_2) 
               
               
                 Example 5 
                 Original 
                 0.79 
                 0.87 
                 14 
                 36 
                   
               
               
                   
                 structure 
                   
                   
                   
                   
                   
               
               
                   
                 Improved 
                 0.94 
                 1.22 
                 −13.45 
                 15 
                 A1 &gt; (A3_1+ 
               
               
                   
                 structure 
                   
                   
                   
                   
                 A3_2) 
               
               
                   
                   
                   
                   
                   
                   
                 A1 &gt; Aeff 
               
               
                   
                   
                   
                   
                   
                   
                 B1 &lt; B3 
               
               
                   
               
            
           
         
       
     
     In table 2, ΔB is the difference between the magnetic field density B 1  of the inner leg  100  and the magnetic field density B 3  of the outer leg  102 . Once the absolute value of ΔB (i.e. |ΔB|) decreases or B 1  is smaller than B 3 , the differential temperature ΔT and the thermal stress will decrease correspondingly. 
     In another embodiment, the first bottom portion  104  or the second bottom portion  106  may comprise a heat dissipating surface for in contact with a heat dissipating module (not shown) for heat dissipation. If the heat dissipating surface of the first bottom portion  104  is in contact with a heat dissipating module for heat dissipation, the cross-sectional area of the first bottom portion  104  may be smaller than the cross-sectional area of the second bottom portion  106 . Alternatively, if the heat dissipating surface of the second bottom portion  106  is in contact with a heat dissipating module (not shown) for heat dissipation and the cross-sectional area of the second bottom portion  106  may be smaller than the cross-sectional area of the first bottom portion  104 . 
     Referring to  FIGS.  7  and  8   ,  FIG.  7    is a perspective view illustrating a magnetic body  10 ′ according to another embodiment of the invention and  FIG.  8    is a perspective view illustrating a magnetic body  10 ″ according to another embodiment of the invention. 
     As shown in  FIG.  7   , the magnetic body  10 ′ comprises one outer leg  102 . As shown in  FIG.  8   , the magnetic body  10 ″ comprises four outer legs  102 . The thermal stress corresponding to the magnetic bodies  10 ,  10 ′ and  10 ″ may be reduced by 50%, 30% and 55% respectively. It should be noted that, for the magnetic body  10 ″ shown in  FIG.  8   , the cross-sectional area of the inner leg  100  is larger than the total cross-sectional area of the four outer legs  102 . Furthermore, a ratio between the cross-sectional area of the inner leg  100  and the total cross-sectional area of the outer leg(s)  102  may be between 1.01 and 1.6, such that the thermal stress will be further reduced. 
     In an embodiment, the cross-sectional area of the inner leg  100  may be a minimum value along a height direction of the inner leg  100  (i.e. the direction of H shown in  FIG.  1   ) and the total cross-sectional area of the two outer legs  102  may be a minimum value along a height direction of the two outer legs  102  (i.e. the direction of H shown in  FIG.  1   ). 
     In another embodiment, the cross-sectional area of the inner leg  100  may be identical along a height direction of the inner leg  100  (i.e. the direction of H shown in  FIG.  1   ) and the total cross-sectional area of the two outer legs  102  may be identical along a height direction of the two outer legs  102  (i.e. the direction of H shown in  FIG.  1   ), such that the manufacturing cost can be reduced. 
     As mentioned in the above, the invention adjusts and optimizes the cross-sectional areas of the inner leg and the at least one outer leg of the magnetic body to improve the characteristics of the magnetic component. Specifically, the cross-sectional area of the inner leg is larger than the total cross-sectional area of the at least one outer leg. Furthermore, the cross-sectional area of the inner leg may be larger than the effective cross-sectional area of the magnetic body and/or the cross-sectional area of the inner leg may be larger than the total cross-sectional area of the first bottom portion and the second bottom portion. When the structure of the magnetic body conforms to the aforesaid geometric criteria, the magnetic body can uniformize magnetic field distribution and then avoid heat accumulation to improve thermal balance for the magnetic component. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.