Abstract:
The present publication relates to one or more coils for axial flux PM-motor according to the description where the coil(s) are made up of coil elements of lap type with slots where the coil element is manufactured by casting, or a combination off milling or punching and water cutting or wire cutting or similar. It is also made slots  101  for the connector which connects each coil element.

Description:
SUMMARY 
       [0001]    This patent is an extension of Patent WO 2012/128646 1A “Coil assembly for three phased transversal axial flux multi disk machines”, which includes machines with other phase numbers, winding patterns and manufacturing techniques. 
         [0002]    WO 2012/1286461A describes how a 3 phased axial flux PM-motor can be made from coil elements where you get a completely flat coil by making cuts in the thread so the coil elements fit together in a jigsaw. 
         [0003]    The most important new in this patent application contra WO 2012/128646 1A is general claims on other types of coils and optimal solutions for coil shape and production methods. 
     
    
     
       DESCRIPTION 
         [0004]    In this patent we keep the numbering from patent WO 2012/128646 1A but new details has numbering form  100 - 111 . New figures have numbering from  20 - 28 . 
           [0005]      FIG. 20  show the same type of coil element as  FIGS. 1 and 9 . The new details here are:
       the connector  29  is made part of the coil element  15 . This eliminates one contact point.   It is made slots  101  for connector  29  and the connector  29  is given a thickness so it fit into the slot  101 . This ensures that the connector does not build extra thickness compared to the coil. It is three slots  101  for connectors from three other coil elements. This coil is lap winding of AA-BB-CC type meaning that two adjacent coil legs  13 ,  14  belong to the same phase. Then it is necessary with 4 coil slots  1 - 4  both at top and bottom of each coil element  15 .       
 
       
    
    
       [0008]    Slots with the same number contain wires from the same phase. This holds for all coil slot numbering. 
         [0009]    Coil element  15  can be made by casting or a combination off milling or punching and water cutting or wire cutting. This allows the conductor  9  in the active area under the magnet to have varying thickness. Note how the thickness increases with distance from motor shaft centre line. This gives increased current density and increase heat generation closer to centre, but this heat is very effective distributed along the conductor so it is net heat generated in the conductor which counts. 
         [0010]      FIG. 21  show a complete assembly based new configuration of coil elements  15 . Coil element  16  and  19  belongs to phase 1, coil elements  17  and  20  belongs to phase 2 and coil elements  18  and  21  belongs to phase 3. Note that the wires in the paired elements are mirrored so the current can go in the same direction in up to 6 consecutive coil legs  13  and  14 . This gives a lower pole number. 
         [0011]    Note how the Iron  35  is visible between the coil layers  103 . Also note the gap  102 . It is difficult to recognize this on a standard patent drawing, but it is possible to see right through the coil through this gap. There are only 4 gaps visible on this view but there are of course gaps everywhere which cooling fluid can go through. 
         [0012]    It is possible to make slots in other types of coil elements to make other types of coils for axial flux machines. A small change is the two phase design show in  FIG. 22 . The coil is identical to  FIG. 21  except that the connectors  29  connect every second coil element instead of every third. For this reason the coil elements are numbered  18 - 21  instead of  16 - 21  as in  FIG. 21 . This is not the preferred way to make a 2 phased motor because a 2 phased motor can be made with coil slots  1  and  3  only as shown in  FIG. 28 . This gives less end windings. 
         [0013]    A more significant change would be coil of wave design. The advantage of wave windings is that you do not need the connectors you need in lap windings.  FIG. 23  show one phase  104  of a coil for a 3 phased motor with 32 magnets on each rotor disk. This phase  104  can be cut in one single piece or you can make it of many elements if the machine is large. The holes  107  are for connecting coil elements. 
         [0014]      FIG. 24  show the complete coil  108  made up of phase  104 ,  105  and  106 . The coil  108  is wave winding of ABC-ABC type and only need only two slots  1 , 3  in each “coil element”. This gives smaller end windings but it also double the number of magnets poles on the rotor disk. This gives a penalty because the edge of the magnet contributes less than the centre to the magnetic field because of field leakage to the adjacent magnet. 
         [0015]      FIG. 25  show a complete coil  109  of 3 phased wave winding type. Here the entire coil elements  109 A-C consists of a single wire. Note that  109 A has all the cuts  1 A,  3 A facing up. When assembling the coil  109  this coil element  109 A is places first on the table. Coil element  109 B has half of its cuts  1 B facing up, and half of its cuts  3 B facing down. This coil element  109 B is placed on top of coil element  109 A so the slots  1 A and  3 B goes into each other. The coil element  109 C goes is placed on the table last. The slots  1 C fits into slots  3 A while slots  3 C fits into slot  1 B. The advantage of this design is that it is possible to assemble the coils easily. Theoretically a wave coil consisting of identical coil elements could be assembled but is would require that the coil elements was braided together or that all 3 elements was manufactured at the same time by metal printing techniques, and that is not practical. Small plastic pieces  110  or similar is placed in the cuts  1  and  3  to provide extra electric insulation in the cuts. The coil contacts  111  are placed on outside the coil, making this a motor/generator with a rotating centre shaft. Had the coil contacts  111  been placed on the inside of the coil, the coil would have been suited as a wheel motor. 
         [0016]    To get a two phased machine coil element  109 B can be skipped from the coil  109 . The slots which then are not filled can then also be skipped. If coil element  109 A and  109 C is used directly there will be open space in coil  109 , but it is easy to imagine how the slots must be moved to make an optimal two phase coil. 
         [0017]    The lap winding coils shown in  FIG. 20-23  and  FIG. 28  can be assembled but inserting the last coil element to finish the coil can be a little tricky because it requires wide tolerances and some bending to get the last coil elements together. Imagine that you make a circle of standing domino pieces arranged so that if you tip any piece all will fall. Then tip one piece. Now if you want to remove one fallen piece you will have to lift another piece. Finishing the coils in  FIG. 20-23  is similar to put the removed domino piece back, but more complicated because of the slots. You have to bend a large part of the entire coil to get the last elements  15  in place. For large coils for e.g. wind turbines generators this is undesirable because it makes assembly and disassembly nearly impossible. 
         [0018]    The idea of changing the slots in some of the coil elements  15  to make assembly easier is also applicable to lap winding. This gives more types of coil elements, but also easier assembly. An example of this is shown in  FIG. 26 . This is a tree phase coil made of lap windings. The coil elements are given 6 different shapes  16 - 21 . 
         [0019]    For coil element  16  is shaped so that all coil slots ( 1 A- 4 A) and all the connector slots  101 AA- 101 AC are all facing up on the figure. The connector  29 A is along the table. For coil element  19  is shaped so that all coil slots ( 1 B-BA) and all the connector slots  101 BA- 101 BC are all facing down on the figure. The connector  29 B is in the air. Coil elements  16  and  19  belong to phase 1. 
         [0020]    For coil element  17  is coil slot  3 B is facing down while the rest of the coil slots  1 B, 2 B and  4 B are facing up. Connector slot  101 CA is facing down while connector slot  101 CB and  101 CC are facing up. The connector  29 C is along the table. For coil element  20  is coil slot  3 D is facing up while the rest of the coil slots  1 D, 2 D and  4 D are facing down. Connector slot  101 DA is facing up while connector slot  101 DB and  101 DC are facing down. The connector  29 C is in the air. Coil elements  17  and  20  belong to phase 2. 
         [0021]    For coil element  18  is coil slot  3 E and  4 E is facing down while the rest of the coil slots  1 E and  2 E are facing up. Connector slot  101 EA and  101 EB is facing down while connector slot  101 EC is facing up. The connector  29 C is along the table. For coil element  21  is coil slot  3 F and  4 F is facing up while the rest of the coil slots  1 F and  2 F are facing down. Connector slot  101 FA and  101 FB is facing up while connector slot  101 FC is facing down. The connector  29 F is in the air. Coil elements  18  and  21  belong to phase 3. 
         [0022]    That a slot is facing down means that it is not visible when seen as shown on  FIG. 26 . That the connector  29  is along the table means that the connector would touch the table when the coil elements are placed on a table as shown on  FIG. 26 . That the connector  29  is in the air means that the connector is not touching the table when the coil element  15  is placed on a table as shown in  FIG. 26 . 
         [0023]    Note that coil element  16  and  19  are identical except for the connector. 
         [0024]    Note that coil element  17  and  20  are identical except for the connector. 
         [0025]    Note that coil element  18  and  21  are identical except for the connector. 
         [0026]    This means that if the connector are manufactured separate 3 types of coil elements are enough. However this will give twice as many contacts. The assembled coil elements are shown in  FIG. 27 . 
         [0027]    For a two phased motor the same arrangement as shown in  FIG. 27  the coil elements will only have two slots. Including connectors there will be 4 types of coil elements  15 . Excluding connectors 2 type of coil elements  15  is enough. Similar arrangements can also be made for 4 and more phased motors, but it is doubtful that 4 or more phased machines with this kind of coils will be made because the end windings will be unacceptable large. 
         [0028]    There are more possible coil configurations for axial flux machines. These configurations can be made completely flat by making coil elements with slots which fit into a flat 3D jigsaw as described here and in patent WO 2012/128646 1A.