Patent Publication Number: US-6661326-B2

Title: Wire-winding structure and method for a transformer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a wire-winding structure and a wire-winding method, and more particularly to a wire-winding structure and wire-winding method applied to a transformer. 
     2. Description of the Prior Art 
     Please refer to FIG. 1A, showing a bobbin  1  of a conventional transformer. The bobbin  1  includes a primary winding side  11  and a secondary winding side  12 . A plurality of slots  14  are formed in the secondary winding side  12 . A plurality of pins  15  are disposed at two ends of the base  13  of the bobbin  1  to be connected with a printed circuit board at users&#39; end. Conventional winding way of the bobbin is shown in FIG.  1 B. The wire is wound on the slots  14 . Specifically speaking, the wire is first soldered to a starting pin  151 . After winding on the first slots  14 , the wire traverses a wire-traversing groove  16  and then is wound on the second and third slots. After the entire array of slots is wound with the wire, the wire is pulled back through a wire-traversing structure  17  to a pin  152  and soldered to the pin  152 . The bobbin  1  with winding wire is then combined with two E-type iron core structures  18  to constitute the transformer. 
     However, there is a gap formed at the connection portion between the two iron core structures. Thus, when the magnetic field encounters different media (space or glue), instability is generated. This affects the windings, and causes loss of transformer power. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to solve the above-mentioned problems by providing a wire-winding structure and method for a transformer. The transformer power is thereby enhanced. 
     According to a first aspect of the present invention, the wire-winding method applied to a transformer includes the following steps. A bobbin which includes a plurality of pins and a plurality of slots formed on the external surface is provided. A wire is wound from a first pin and successively wound on the rest of the plurality of slots, but not on the slot adjacent to a predetermined connection portion between iron core structures of the transformer. The wire is soldered to a second pin and the bobbin with the winding wire is combined with the iron core structures to constitute the transformer. 
     Preferably, the bobbin can include a primary winding side and a secondary winding side, and the plurality of slots are formed on the secondary winding side. The bobbin is provided with a plurality of outwardly protruding insulating flanges on the external surface of the bobbin to form the plurality of slots. 
     Moreover, the bobbin includes a base, and the plurality of pins are disposed at two ends of the base for connection to a printed circuit board. 
     According to another aspect of the present invention, the wire-winding structure of the transformer includes a bobbin and the bobbin is provided with a plurality of slots on the external surface of the bobbin. The slots are wound with a wire, but a slot adjacent to a predetermined connection portion between iron core structures of the transformer is not wound with the wire. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, given by way of illustration only and thus not intended to be limitative of the present invention. 
     FIG. 1A is a schematic diagram showing a bobbin of a conventional transformer. 
     FIG. 1B is a schematic diagram showing the wire-winding method of a bobbin of a conventional transformer. 
     FIG. 2A is a schematic diagram showing the wire-winding method of the transformer of the present invention. 
     FIG. 2B is a schematic diagram showing the combination of the transformer of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention discloses a wire-winding structure and a wire-winding method applied to a transformer. FIG. 2A shows a bobbin according to a preferred embodiment of the present invention, which is used to further describe the technique and feature of the present invention. The bobbin  2  includes a primary winding side  21  and a secondary winding side. In the secondary winding side, a plurality of insulating flanges outwardly protrude from the external surface of the bobbin  2 . The secondary winding side is partitioned by the insulating flanges into a plurality of slots  24 . A plurality of pins are disposed at two ends of the base  23  of the bobbin  2  for connection to a printed circuit board at the users&#39; end. The wire-winding method is described below. A wire is wound on the slots  24 . First, the wire is soldered to a starting pin (or a first pin)  251  and wound on the first slot. After the winding on the first slot is complete, the wire traverses a wire-traversing groove  26  of the insulating flanges, and then is wound on a second slot. The wire is not wound on a slot  241  adjacent to a predetermined connection portion  29  between iron core structures of the transformer (as shown in FIG.  2 B), and then is wound on the next slot. Next, the winding continues until the rest of the slots are wound. Next, the wire is pulled back through a wire-traversing structure  27  of the insulating flanges to a soldering pin (or a second pin)  252  and soldered to the second pin  252 . Finally, the bobbin  2  with winding wire is combined with two iron core structures  28  to constitute the transformer. Of course, the wire-winding method of the present invention can be applied to a transformer combined by a bobbin and iron core structures with other shapes. 
     There is a gap formed at the connection portion between the two iron core structures. Thus, when the magnetic field encounters different media (space or glue), instability is generated. This affects the windings, and causes loss of transformer power. To prevent the above problems, the wire is not wound on a slot  241  adjacent to a predetermined connection portion  29  between iron core structures in the present invention. Thus, not only are the various electrical properties of the transformer enhanced, but also the coupling properties of the primary winding side and the secondary winding side are improved. This effectively decreases magnetic leakage of the secondary winding side and decreases the stray capacitance. Transformer power is also enhanced. 
     The foregoing description of the preferred embodiments of this invention has been presented for purposes of illustration and description. Obvious modifications or variations are possible in light of the above teaching. The embodiments were chosen and described to provide the best illustration of the principles of this invention and its practical application to thereby enable those skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.