Patent Publication Number: US-2003227366-A1

Title: Inductor structure and manufacturing method for the inductor structure

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention is related to an inductor structure and a manufacturing method for the inductor structure. The manufacturing method is simplified and the inductance of the inductor is changeable.  
       [0002] A conventional inductor is used to insulate DC and AC signals from each other. The conventional inductors are widely used various circuits such as stereo, sound divider, modem, etc. for regulating signal frequency of current transmission. U.S. Pat. Nos. 7,125,880 and 7,110,535 disclose typical conductors.  
       [0003] A conventional inductor includes a housing and an iron core (magnetic core) fixed on an end face of the housing. A coil is wound around the iron core. Two terminals of the coil extend from two sides of the housing and are bent and soldered. Then, a cap member is mounted on the housing to seal a cavity of the housing in which the coil is disposed. A base seat having an external conductive terminal is connected with the bottom side of the housing to make the terminals of the coil contact with the external conductive terminal. In the conventional structure, a ceramic mud is often filled into the cavity to fix the coil.  
       [0004] It is relatively troublesome to manufacture the above conventional inductor. Taiwanese Patent No. 89110219 discloses a manufacturing method for plate-shaped conductor. Taiwanese Patent No. 87113898 discloses a manufacturing method for an inductor. Taiwanese Patent No. 88121966 discloses a winding type inductor. Taiwanese Patent No. 88108824 discloses a manufacturing method for an inductor. Taiwanese Patent No. 8911869 discloses an inductor. Taiwanese Patent No. 89219886 discloses a magnetic core of an inductor. Taiwanese Patent No. 89200104 discloses an iron core structure of mini-inductor. These patents provide improved manufacturing methods for inductors.  
       [0005] It is known that the current passing through the inductor changes to cause magnetic line variation rate. That is, the greater the inductance is, the greater the magnetic line variation rate is or the greater the dielectric capacity of magnetic core relative to air is. Therefore, when changing the inductance of the conventional inductor, it is often necessary to recast the mold and provide another specification of coil and magnetic core. This increases the cost. The above patents all fail to provide a measure to solve this problem.  
       SUMMARY OF THE INVENTION  
       [0006] It is therefore a primary object of the present invention to provide an inductor structure and manufacturing method for the inductor structure. The inductor structure includes a frame body defining a cavity having two openings and a conductive coil unit fitted on an iron core. The coil unit and the magnetic core are movably disposed in a predetermined position in the cavity. A filling material is filled into the cavity to fix the coil unit and the magnetic core. The coil unit has two flattened terminals extending out of the cavity in a direction normal to the axis of the iron core. The terminals are bent from the frame body and fixed on a wall of the frame body. When it is desired to change the inductance of the inductor, a user only needs to replace the iron core and the coil. Accordingly, without recasting the mold, another specification of inductance or magnetic line can be achieved.  
       [0007] It is a further object of the present invention to provide the above inductor structure and manufacturing method for the inductor structure. A filling material is then filled into the cavity of the frame body to locate the coil unit and the iron core in a fixed position in the cavity. The terminals are bent downward from the frame body and fixedly received in dents formed on the bottom wall of the frame body.  
       [0008] The present invention can be best understood through the following description and accompanying drawings wherein: 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009]FIG. 1 is a perspective exploded view of the inductor of the present invention;  
     [0010]FIG. 2 is a perspective assembled view of the inductor of the present invention;  
     [0011]FIG. 3 is a bottom perspective view of the inductor of the present invention according to FIG. 2; and  
     [0012]FIG. 4 is a flow chart of the manufacturing method for the inductor of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0013] Please refer to FIGS. 1 and 2. The inductor  10  of the present invention includes a frame body  11  made of iron material. The frame body  11  has four side walls  12  defining a cavity  13  having two openings in a horizontal reference axis. The inductor  10  further includes a conductive coil unit  20  which is an annular body. The coil unit  20  is fitted around an iron-made cylindrical magnetic core  30 . In the horizontal reference axis, the conductive coil unit  20  has two flat terminals  21 . The coil unit  20  fitted around the magnetic core  30  is movably disposed in the cavity  13  of the frame body  11 . The terminals  21  of the coil unit  20  extend out of the cavity  13  from the openings of the frame body  11 . As shown in FIG. 2, a filling material  40  is filled in the cavity  13  for fixing the coil unit  20  and the magnetic core  30  in a predetermined position in the cavity  13 .  
     [0014] Referring to FIG. 3, the bottom wall  12 ′ of the frame body  11  is formed with dents  14  corresponding to the terminals  21 . The terminals  21  of the coil unit  20  are bent downward from the openings of the frame body  11  and received in the dents  14  to form the inductor  10 .  
     [0015]FIG. 4 shows the manufacturing method for the inductor  10  of the present invention. The manufacturing method includes a step of providing an annular conductive coil  20  with two flattened terminals  21 . In a preferred embodiment, the flattened terminal  21  has a thickness of about 0.35 mm and a width of about 3.6˜3.8 mm. In practice, the paint on the terminal  21  is scraped off and then the terminal  21  is electroplated with tin. In a next step of the manufacturing method, the coil  20  is placed onto the magnetic core  30 . Then, a tool is used to place the coil  20  into the cavity  13  of the frame body  11  and locate the coil  20  in a predetermined position. Basically, the magnetic core  30  is positioned at the center of the cavity  13  with the terminals  21  respectively extending out of the cavity  13  from the openings of the frame body  11 . A filling material  40  is then filled into the cavity  13 . Then, the terminals  21  are bent downward from the openings of the frame body  11  and fixedly received in the dents  14  of the bottom wall  12 ′ of the frame body  11 .  
     [0016] According to the above arrangement, the present invention has the following advantages:  
     [0017] 1. The cavity  13  of the frame body  11  has two openings so that the conductive coil unit  20  and the magnetic core  30  are movably disposed in the cavity  13 . When it is desired to change the inductance, a user only needs to remove the filling material and replace the conductive coil  20 . This lowers the manufacturing cost of the inductor.  
     [0018] 2. The frame body  11  and the magnetic core  30  can be reused, while having different inductances. Accordingly, it is no more necessary to recast the mold as in the conventional measure.  
     [0019] 3. The assembly of the frame body  11 , magnetic core  30  and conductive coil  20  has a structure much simpler than that of the conventional structure including a cap, a base seat and a housing soldered together. Accordingly, the shortcomings existing in the conventional manufacturing method are eliminated.  
     [0020] The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.