Abstract:
The present invention relates to a slotless winding for a rotating electric machine and a manufacturing method thereof. The slotless winding includes at least one flexible printed circuit board having at least one circuit, and one piece of flexible printed circuit board(s) is curved or a plurality of pieces of flexible printed circuit board(s) is mutually combined to form a barrel shape, thereby simplifying the procedure of manufacturing the slotless winding, improving production speed and reliability, and enabling diversified designing schemes to meet the demands of the rotating electric machine. In addition, it is not necessary for the coil winding to be cured for assembling, and assembling yield is thus enhanced.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a slotless winding for a rotating electric machine and a manufacturing method thereof. More particularly, the present invention relates to a slotless winding for a rotating electric machine and formed on a flexible printed circuit board and a manufacturing method thereof. 
         [0003]    2. Description of the Related Art 
         [0004]      FIGS. 1   a - 1   d  show schematic views of four kinds of conventional motors. In the four conventional motors, the same elements are labeled with the same reference numbers. In  FIG. 1   a , a first kind of conventional motor  1 A includes a housing  11 , a winding  12 , a magnet  13 , a shaft  14 , and a gap  15 . The winding  12  is fixed on the housing  11 , the magnet  13  is fixed on the shaft  14 , and the gap  15  exists between the winding  12  and the magnet  13 . In electronic machinery, the winding and the components connected thereto are referred to as a primary, and the magnet and the components connected thereto are referred to as a secondary. After energization, the magnetic force between the magnet  13  and the winding  12  can drive the primary and the secondary to rotate respective to each other. 
         [0005]    In  FIG. 1   b , the elements of a second kind of conventional motor  1 B are substantially the same as elements of the first kind of conventional motor  1 A, except that the arrangement thereof is different. The second kind of conventional motor  1 B includes a housing  11 , a winding  12 , a magnet  13 , a shaft  14 , a gap  15 , and a back iron  16 . The magnet  13  is fixed on the housing  11 , the winding  12  and the back iron  16  are fixed on the shaft  14 , and the gap  15  exists between the winding  12  and the magnet  13 . After energization, the magnetic force between the magnet  13  and the winding  12  can drive the primary and the secondary to rotate relative to each other. 
         [0006]      FIG. 1   c , the elements of a third kind of conventional motor  1 C are substantially the same as elements of the first kind of conventional motor  1 A, except that the arrangement thereof is different. The third kind of conventional motor  1 C includes a housing  11 , a winding  12 , a first magnet  131 , a second magnet  132 , a shaft  14 , a first gap  151 , and a second gap  152 . The first magnet  131  is fixed on the housing  11 , the second magnet  132  is fixed on the shaft  14 , the first gap  151  exists between the winding  12  and the first magnet  131 , and the second gap  152  exists between the winding  12  and the second magnet  132 . 
         [0007]    In  FIG. 1   d , the elements of a fourth kind of conventional motor  1 D are substantially the same as elements of the first kind of conventional motor  1 A, except that the arrangement thereof is different. The fourth kind of conventional motor  1 D includes a housing  11 , a first winding  121 , a second winding  122 , a magnet  12 , a shaft  14 , a first gap  151 , a second gap  152 , and a back iron  16 . The first winding  121  is fixed on the housing  11 , the second winding  122  and the back iron  16  are fixed on the shaft  14 , the first gap  151  exists between the magnet  13  and the first winding  121 , and the second gap  152  exists between the magnet  13  and the second winding  122 . 
         [0008]    In the four kinds of conventional motors  1 A,  1 B,  1 C, and  1 D, the windings (including the winding  12 , the first winding  121 , and the second winding  122 ) are coil windings, as shown in  FIG. 2 . Reference to the form of the coil winding can be seen in U.S. Pat. No. 6,507,991, U.S. Pat. No. 6,791,224, U.S. Pat. No. 5,998,905, U.S. Pat. No. 5,715,590, U.S. Pat. No. 5,606,791, U.S. Pat. No. 5,197,180 etc. The method of manufacturing the coil winding is as follows. First, a winding machine is used to wind the coil, and a connection wire is reserved and fixed on a mold holder to form an initial cylindrical coil. Then, the initial cylindrical coil is flattened and curled to an annular shape, and then cured and shaped by using resin or self-adhering enamel wire. Finally, the coil is placed into the motor. 
         [0009]    Another manufacturing method is that a purpose made winding machine is directly used to fabricate the coil with the slotless winding design on special mold and jig. The processes of the above two methods are quite complex and require the matching of special jig and mold holder, and if the copper wire used for winding is slim, it is necessary for the winding machine to have corresponding tension controlling device to prevent the wires from breaking. After the winding is finished, it is still necessary to perform plastic compression, shaping, and curing procedures, so it is disadvantageous for mass production assembly. 
         [0010]    Therefore, it is necessary to provide an innovative and progressive slotless winding for a rotating electric machine and a manufacturing method thereof, so as to solve the above problems. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is mainly directed to a slotless winding for a rotating electric machine, which includes at least one flexible printed circuit board having at least one circuit. One piece of flexible printed circuit board(s) is curved or wound, or a plurality of pieces of flexible printed circuit board(s) are mutually combined to form a barrel shape. 
         [0012]    The present invention is further directed to a method of manufacturing a slotless winding for a rotating electric machine, which includes the following steps: (a) providing at least one flexible printed circuit board; (b) forming at least one circuit on a surface of or inside each flexible printed circuit board; and (c) making the flexible printed circuit board(s) form a barrel shape. 
         [0013]    The advantage of the present invention is that the procedure of manufacturing the slotless winding is simplified, and production speed and reliability are enhanced. Further, the winding can be designed in various ways to meet the demand of motor or generator, so as to increase the applicability of coil copper wire and to greatly improve the performance. In addition, the coil is manufactured through a semiconductor process, and thus the industrial value and technical threshold of the motor are increased. Finally, it is not necessary for the coil to be cured for assembling, thus enhancing the assembling yield. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1   a  is a schematic view of a first kind of conventional motor; 
           [0015]      FIG. 1   b  is a schematic view of a second kind of conventional motor; 
           [0016]      FIG. 1   c  is a schematic view of a third kind of conventional motor; 
           [0017]      FIG. 1   d  is a schematic view of a fourth kind of conventional motor; 
           [0018]      FIG. 2  is a schematic view of a conventional coil winding; 
           [0019]      FIG. 3   a  is a schematic top view of a flexible printed circuit board according to a first embodiment of the present invention, in which only a first circuit is shown; 
           [0020]      FIG. 3   b  is a schematic top view of the flexible printed circuit board according to a first embodiment of the present invention, in which only a second circuit is shown; 
           [0021]      FIG. 4  is a schematic top view of the flexible printed circuit board according to a second embodiment of the present invention; 
           [0022]      FIG. 5   a  is a schematic top view of the flexible printed circuit board according to a third embodiment of the present invention, in which only a first circuit is shown; 
           [0023]      FIG. 5   b  is a schematic top view of the flexible printed circuit board according to a third embodiment of the present invention, in which only a second circuit is shown; 
           [0024]      FIG. 6  is a schematic top view of the flexible printed circuit board according to a fourth embodiment of the present invention; 
           [0025]      FIG. 7  is a schematic top view of the flexible printed circuit board according to a fifth embodiment of the present invention; 
           [0026]      FIG. 8  is a schematic top view of the flexible printed circuit board according to a sixth embodiment of the present invention; 
           [0027]      FIG. 9  is a schematic view of a first type slotless winding of the present invention for the first kind of conventional motor; 
           [0028]      FIG. 10  is a schematic view of a second type slotless winding of the present invention for the first kind of conventional motor; 
           [0029]      FIG. 11  is a schematic view of a third type slotless winding of the present invention for the first kind of conventional motor; and 
           [0030]      FIG. 12  is a flow chart of the method of manufacturing the slotless winding for the rotating electric machine of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    The slotless winding of the present invention can be for a rotating electric machine including but not limited to motor, generator, etc. The slotless winding of the present invention includes at least one flexible printed circuit board, the flexible printed circuit board has at least one circuit, and one piece of flexible printed circuit board(s) is curved and wound or a plurality of pieces of flexible printed circuit board(s) are mutually combined to form a barrel shape. In application, the present invention uses the slotless winding with the barrel shape formed by the flexible printed circuit board(s) to replace the conventional coil windings (including the winding  12  ( FIGS. 1   a ,  1   b , and  1   c ), the first winding  121 , and the second winding  122  ( FIG. 1   d )). 
         [0032]    In the present invention, the forming method of the circuit is selected from electrocasting, imprinting, screen printing, photolithography, ink-jet printing, and other semiconductor processes, and is preferably electrocasing. The circuit can be formed on two surfaces of or inside the flexible printed circuit board. Preferably, the circuit comprises a plurality of parallel wires. In an embodiment, in order to increase the layout density, the circuit has a first circuit and a second circuit, the first circuit and the second circuit are respectively located on different layers of the flexible printed circuit, that is, the first circuit and the second circuit can be located on two surfaces of the flexible printed circuit, or can be located on different layers in the flexible printed circuit board. In this case, the flexible printed circuit board must have a plurality of vias for connecting the first circuit and the second circuit. 
         [0033]      FIGS. 3   a  and  3   b  show schematic top views of the flexible printed circuit board according to a first embodiment of the present invention.  FIG. 3   a  only shows the first circuit, and  FIG. 3   b  only shows the second circuit. The flexible printed circuit board  2  has a first surface  21 , a second surface (not shown), and a circuit. The first surface  21  has three first winding regions  211 , the second surface has three second winding regions  241 , and the first winding regions  211  correspond to the second winding regions  241 . In other application, the number of the first winding region  211  and the second winding region  241  is not limited to three. 
         [0034]    The circuit has a first circuit  22  and a second circuit  23 , the first circuit  22  is located on the first surface  21 , and the second circuit  23  is located on the second surface and is shown by dashed circuit. The first circuit  22  includes three first winding coils  221 , and each first winding coil  221  is located in each first winding region  211 . The first winding coil  221  comprises a plurality of mutually parallel coils wound by a wire, and in this embodiment, the first winding coil  221  is octagonal. However, in other application, the first winding coil  221  can also be triangular, rhombic, hexagonal, polygonal, oval, round, or composed of a plurality of circular arcs. 
         [0035]    The second circuit  23  includes three second winding coils  231 , and each second winding coil  231  is located in each second winding region  241 . The second winding coil  231  comprises a plurality of mutually parallel coils wound by a wire, and in this embodiment, the second winding coil  231  is octagonal. However, in other application, the first winding coil  231  can also be triangular, rhombic, hexagonal, polygonal, oval, round, or composed of a plurality of circular arcs. In this embodiment, the pattern of the first circuit  22  is the same as the pattern of the second circuit  23 , that is, the pattern of the first winding coil  221  is the same as the pattern of the second winding coil  231 , and they are mirror images of each other. In addition, the flexible printed circuit board  2  further has a plurality of vias  25  for connecting the first circuit  22  and the second circuit  23 . 
         [0036]      FIG. 4  shows a schematic top view of the flexible printed circuit board according to a second embodiment of the present invention. The flexible printed circuit board  3  has a first surface  31 , a second surface (not shown), and a circuit. The circuit has a first circuit  32  and a second circuit  33 , the first circuit  32  is located on the first surface  31 , and the second circuit  33  is located on the second surface and is shown by dashed circuit. The pattern of the first circuit  32  comprises a plurality of mutually parallel first wires  321 , and the first wires  321  are quasi-U-shaped with openings in the horizontal direction (to the right in the drawing). The pattern of the second circuit  33  comprises a plurality of mutually parallel second wires  331 , and the second wires  331  are quasi-U-shaped with openings in the horizontal direction (to the left in the drawing). 
         [0037]    In this embodiment, the pattern of the first circuit  32  is the same as the pattern of the second circuit  33 , that is, the pattern of the first wires  321  is the same as the pattern of the second wires  331 , and they are mirror images of each other. In addition, the flexible printed circuit board  3  further has a plurality of vias (not shown) for connecting the first circuit  32  and the second circuit  33 , so as to form a plurality of mutually parallel octagonal coils. 
         [0038]      FIGS. 5   a  and  5   b  show schematic top views of the flexible printed circuit board according to a third embodiment of the present invention.  FIG. 5   a  only shows a first circuit, and  FIG. 5   b  only shows a second circuit. The flexible printed circuit board  4  has a first surface  41 , a second surface (not shown), and a circuit. The circuit has a first circuit  42  and a second circuit  43 , the first circuit  42  is located on the first surface  41 , and the second circuit  43  is located on the second surface and is shown by dashed circuit. The pattern of the first circuit  42  comprises a plurality of wave-shaped first wires  421 , and the first wires  421  are mutually parallel. The pattern of the second circuit  43  comprises a plurality of wave-shaped second wires  431 , and the second wires  431  are mutually parallel. 
         [0039]    In this embodiment, the pattern of the first circuit  42  is the same as the pattern of the second circuit  43 , that is, the pattern of the first wires  421  is the same as the pattern of the second wires  431 , and they are mirror images of each other. In addition, the flexible printed circuit board  4  further has a plurality of vias (not shown) for connecting the first circuit  42  and the second circuit  43 . 
         [0040]      FIG. 6  shows a schematic top view of the flexible printed circuit board according to a fourth embodiment of the present invention. The flexible printed circuit board  5  has a first surface  51 , a second surface (not shown), and a circuit. The circuit has a first circuit  52  and a second circuit  53 . The first circuit  52  is located on the first surface  51 , and is shown by solid circuit. The second circuit  53  is located on the second surface, and is shown by dashed circuit. The pattern of the first circuit  52  comprises a plurality of obliquely parallel first wires  521 , and the pattern of the second circuit  53  comprises a plurality of obliquely parallel second wires  531 . 
         [0041]    In this embodiment, the pattern of the first circuit  52  is the same as the pattern of the second circuit  53 , that is, the pattern of the first wires  521  is the same as the pattern of the second wires  531 , and they are mirror images of each other. In addition, the flexible printed circuit board  5  further has a plurality of vias (not shown) for connecting the first circuit  52  and the second circuit  53 . 
         [0042]    For convenience of illustration, the circuit of each embodiment includes a first circuit and a second circuit disposed on different layers of the flexible printed circuit board. In practical application, the circuit can further include a third circuit, a fourth circuit, etc. disposed on different layers of the flexible printed circuit board, and the number of circuits can be increased as desired. 
         [0043]      FIG. 7  shows a schematic top view of the flexible printed circuit board according to a fifth embodiment of the present invention. A surface  61  of the flexible printed circuit board  6  has a circuit including a wire group  62 . The pattern of the wire group  62  comprises a plurality of mutually parallel wires  621 , and the wires  621  are connected in parallel. 
         [0044]    As used herein, the term “wire group” refers to a set of wires in the circuit of the same layer. Therefore, one winding coil of  FIGS. 3   a  and  3   b  is equivalent to one wire group. 
         [0045]      FIG. 8  shows a schematic top view of the flexible printed circuit board according to a sixth embodiment of the present invention. The flexible printed circuit board  7  has a circuit, and the circuit includes a plurality of wire groups. The circuit of the embodiment as shown in  FIG. 8  includes a first wire group  72  and a second wire group  73 . The pattern of the first wire group  72  comprises a plurality of parallel first wires  721 . The pattern of the second wire group  73  comprises a plurality of parallel second wires  731 . In this embodiment, the pattern of the first wire group  72  is the same as the pattern of the second wire group  73 , that is, the pattern of the first wires  721  is the same as the pattern of the second wires  731 , and they are mirror images of each other. The first wires  721  of the first wire group  72  are mutually connected in parallel, and similarly, the second wires  731  of the second wire group  73  are also mutually connected in parallel. The first wire group  72  and the second wire group  73  are serially connected by at least one wire. The first wire group  72  and the second wire group  73  can be disposed on the same layer of the flexible printed circuit board  7  or disposed on different layers and are connected by vias. 
         [0046]      FIG. 9  shows a schematic view of a first type of slotless winding of the present invention for the first kind of conventional motor. A motor  8  as shown in the drawing is substantially the same as the first kind of conventional motor  1 A as shown in  FIG. 1   a , only except that in the motor  8 , a slotless winding  82  is used to replace the coil winding  12  in the first kind of conventional motor  1 A. The slotless winding  82  is the first type of slotless winding of the present invention, has a three-layer structure, and is formed by joining three flexible printed circuit boards  821  end to end to form a barrel shape and then stacking the three flexible printed circuit boards  821 . In other applications, the first type of slotless winding can be a single flexible printed circuit board  821  joined end to end to form a barrel shape. The flexible printed circuit board  821  is the flexible printed circuit board of the present invention. 
         [0047]      FIG. 10  shows a schematic view of a second type of slotless winding of the present invention for the first kind of conventional motor. A motor  9  as shown in the drawing is substantially the same as the first kind of conventional motor  1 A as shown in  FIG. 1   a , only except that in the motor  9 , a slotless winding  92  is used to replace the coil winding  12  in the first kind of conventional motor  1 A. The slotless winding  92  is the second type of slotless winding of the present invention, and is formed by combining one end of each flexible printed circuit board  921  with one end of an adjacent flexible printed circuit board so as to form a barrel shape. The flexible printed circuit board  921  is the flexible printed circuit board of the present invention. 
         [0048]      FIG. 11  shows a schematic view of a third type of slotless winding of the present invention for the first kind of conventional motor. A motor  9 A as shown in the drawing is approximately the same as the first kind of conventional motor  1 A as shown in  FIG. 1   a , only except that in the motor  9 A, a slotless winding  93  is used to replace the coil winding  12  in the first kind of conventional motor  1 A. The slotless winding  93  is the third type of slotless winding of the present invention, and is formed by winding one piece of flexible printed circuit board  931  for a plurality of turns to form a multi-layer structure. The flexible printed circuit board  931  is the flexible printed circuit board of the present invention. 
         [0049]      FIG. 12  shows a flow chart of a method of manufacturing a slotless winding for a rotating electric machine of the present invention. In step S 101 , at least one flexible printed circuit board is provided. The flexible printed circuit board has a first surface and a second surface, and at least one winding region is pre-divided from the flexible printed board. In step S 102 , at least one circuit is formed on a surface of or inside each flexible printed circuit board. The forming method of the circuit is selected from electrocasting, imprinting, screen printing, photolithography, ink-jet printing, and other semiconductor processes, and is preferably electrocasing. In an embodiment, the circuit includes at least one winding coil, each winding coil being located in each winding region and comprises a plurality of mutually parallel coils wound by a wire. The winding coil can be triangular, rhombic, hexagonal, octagonal, polygonal, oval, round, or composed of a plurality of circular arcs. In the embodiment of the present invention, the circuit comprises a plurality of parallel wires, and the wires are wave-shaped or oblique, and are parallel to one another. 
         [0050]    In the embodiment of the present invention, the circuit has a first circuit and a second circuit, the first circuit and the second circuit are respectively located on different layers of the flexible printed circuit board. Preferably, the first circuit is located on a first surface, and the second circuit is located on a second surface. The flexible printed circuit board further has a plurality of vias for connecting the first circuit and the second circuit. Preferably, the pattern of the first circuit is the same as the pattern of the second circuit, and the pattern of the first circuit and the pattern of the second circuit are mirror images of each other. 
         [0051]    The patterns of the first circuit and the second circuit include but are not limited to the three following types. 
         [0052]    In a first type, the first surface includes at least one first winding region, the second surface includes at least one second winding region, the circuit includes at least one first winding coil and at least one second winding coil, each first winding coil is located in each first winding region, each second winding coil is located in each second winding region, each first winding coil comprises a plurality of mutually parallel coils wound by a wire, and each second winding coil comprises a plurality of mutually parallel coils wound by a wire, as shown in  FIGS. 3   a  and  3   b.    
         [0053]    In a second type, the pattern of the first circuit comprises a plurality of wave-shaped or oblique first wires, and the first wires are mutually parallel; the pattern of the second circuit comprises a plurality of wave-shaped or oblique second wires, and the second wires are mutually parallel, as shown in  FIGS. 5   a ,  5   b , and  6 . 
         [0054]    In a third type, the pattern of the first circuit comprises a plurality of mutually parallel first wires, and the first wires are quasi-U-shaped with openings in the horizontal direction; the pattern of the second circuit comprises a plurality of mutually parallel second wires, and the second wires are quasi-U-shaped with openings in the horizontal direction, as shown in  FIG. 4 . 
         [0055]    In step S 103 , the flexible printed circuit board(s) form(s) a barrel shape. The method of forming the barrel shape includes but is not limited to the three following types. 
         [0056]    In a first method, each flexible printed circuit board is joined end to end to form a barrel shape, and a plurality of flexible printed circuit board are stacked together to form a multi-layer structure, as shown in  FIG. 9 . In a second method, one end of each flexible printed circuit board is combined with one end of a adjacent flexible printed circuit board, so as to form a barrel shape, as shown in  FIG. 10 . In a third method, one piece of flexible printed circuit board is wound for a plurality of turns, so as to form a multi-layer structure, as shown in  FIG. 11 . 
         [0057]    The present invention has the following advantages. 1. The flexible printed circuit board is used to fabricate the winding without iron core, winding types corresponding to motor or generator rotor magnet can be directly drawn on the printed circuit board, and winding is wound or curled to be round or of various shapes to serve as motor or generator stator coil, so as to simplify the process of fabricating the slotless winding. 2. The conductor is patterned on the flexible printed circuit board directly, which is not limited by the conventional method of fabricating the winding, so as to generate various winding types suitable for different motor or generator designs. 3. Wires of different sizes can be directly fabricated, so the thickness of the winding can be controlled to reduce loss of copper, and the windings are mutually stacked in an offset manner with multi-layer layout technique, so as to suit various designs, and to effectively downsize the motor or the generator. 4. After being wound and shaped, the winding fabricated by using flexible printed circuit board has certain strength, so it is not necessary to add the resin for curing. As a result, the procedure is simplified and the subsequent assembling is made convenient, which is helpful to the assembling automatization process after the downsizing of the motor or the generator. 
         [0058]    While several embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention should not be limited to the particular forms as illustrated, and that all modifications which maintain the spirit and scope of the present invention are within the scope defined in the appended claims.