Abstract:
The invention provides slotless electrical machines with mixed ferromagnetic/non-ferromagnetic core (mixed core). The invented slotless electrical machines with mixed core have less attraction and cogging force than conventional electrical machines with ferromagnetic core.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The design of slotless electrical machine includes coils mounted on the core and permanent magnets. In the traditional construction, the core is made of ferromagnetic solid or laminated material (An Analytical Solution for the Normal Force in Linear Actuators by M. A. da Silveira, A. F. Flores Filho, R. P. Homrich—2005 IEEE International Conference on Electric Machines and Drives, May 2005). For this construction, the attraction and cogging force between permanent magnets and ferromagnetic core can be very high. 
         [0002]    The invented construction of slotless electrical machines with mixed core provides less magnetic attraction and cogging force. The mixed core is made of both ferromagnetic and non-ferromagnetic laminations. In the construction with mixed core the attraction and cogging force is reduced. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0003]    FIG.  1 —Linear flat slotless electrical machine with forcer that includes ferromagnetic core. 
           [0004]    FIG.  2 —Invented linear flat slotless electrical machine with forcer that includes mixed core. 
           [0005]    FIG.  3 —Mixed ferromagnetic/non-ferromagnetic core for invented linear flat slotless electrical machine. 
           [0006]    FIG.  4 —Height mixed ferromagnetic/non-ferromagnetic core for invented linear flat slotless electrical machine. 
           [0007]    FIG.  5 —Invented linear flat slotless electrical machine with forcer that includes height mixed core. 
           [0008]    FIG.  6 —Random mixed ferromagnetic/non-ferromagnetic core for invented linear flat slotless electrical machine. 
           [0009]    FIG.  7 —Invented linear flat slotless electrical machine with forcer that includes random mixed core. 
           [0010]    FIG.  8 —Rotary slotless electrical machine with stator that includes ferromagnetic core. 
           [0011]    FIG.  9 —Invented rotary slotless electrical machine with stator that includes mixed core. 
           [0012]    FIG.  10 —Mixed ferromagnetic/non-ferromagnetic core for invented rotary slotless electrical machine. 
           [0013]    FIG.  11 —Radial mixed ferromagnetic/non-ferromagnetic core for invented rotary slotless electrical machine. 
           [0014]    FIG.  12 —Invented rotary slotless electrical machine with stator that includes radial mixed core. 
           [0015]    FIG.  13 —Random mixed ferromagnetic/non-ferromagnetic core for invented rotary slotless electrical machine. 
           [0016]    FIG.  14 —Invented rotary slotless electrical machine with stator that includes random mixed core. 
           [0017]    FIG.  15 —Linear tube slotless electrical machine (internal magnets) with forcer that includes ferromagnetic core. 
           [0018]    FIG.  16 —Invented linear tube slotless electrical machine (internal magnets) with forcer that includes mixed core. 
           [0019]    FIG.  17 —Mixed ferromagnetic/non-ferromagnetic core for invented linear tube slotless electrical machine (internal magnets). 
           [0020]    FIG.  18 —Radial mixed ferromagnetic/non-ferromagnetic core for invented linear tube slotless electrical machine (internal magnets). 
           [0021]    FIG.  19 —Invented linear tube slotless electrical machine (internal magnets) with forcer that includes radial mixed core. 
           [0022]    FIG.  20 —Random mixed ferromagnetic/non-ferromagnetic core for invented linear tube slotless electrical machine (internal magnets). 
           [0023]    FIG.  21 —Invented linear tube slotless electrical machine (internal magnets) with forcer that includes random mixed core. 
           [0024]    FIG.  22 —Linear tube slotless electrical machine (external magnets) with forcer that includes ferromagnetic core. 
           [0025]    FIG.  23 —Invented linear tube slotless electrical machine (external magnets) with forcer that includes mixed core. 
           [0026]    FIG.  24 —Mixed ferromagnetic/non-ferromagnetic core for invented linear tube slotless electrical machine (external magnets). 
           [0027]    FIG.  25 —Radial mixed ferromagnetic/non-ferromagnetic core for invented linear tube slotless electrical machine (external magnets). 
           [0028]    FIG.  26 —Invented linear tube slotless electrical machine (external magnets) with forcer that includes radial mixed core. 
           [0029]    FIG.  27 —Random mixed ferromagnetic/non-ferromagnetic core for invented linear tube slotless electrical machine (external magnets). 
           [0030]    FIG.  28 —Invented linear tube slotless electrical machine (external magnets) with forcer that includes random mixed core. 
       
    
    
     DRAWINGS 
     Reference Numerals 
       [0000]    
       
           10 —Forcer that includes coils and ferromagnetic solid or laminated core, linear flat slotless electrical machine. 
           12 —Coils, linear flat slotless electrical machine. 
           14 —Epoxy 
           16 —Ferromagnetic solid or laminated core, linear flat slotless electrical machine. 
           18 —Magnet track, linear flat slotless electrical machine. 
           20 —Magnetic plate, linear flat slotless electrical machine. 
           22 —Magnets, linear flat slotless electrical machine. 
           24 —Forcer that includes coils and mixed core, linear flat slotless electrical machine. 
           26 —Mixed core, linear flat slotless electrical machine. 
           28  and  36 —Ferromagnetic (oriented or non-oriented) laminations, linear flat slotless electrical machine. 
           30  and  38 —Non-ferromagnetic laminations, linear flat slotless electrical machine. 
           32 —Height mixed core, linear flat slotless electrical machine. 
           34 —Forcer that includes coils and height mixed core, linear flat slotless electrical machine. 
           40 —Random mixed core, linear flat slotless electrical machine. 
           42 —Forcer that includes coils and random mixed core, linear flat slotless electrical machine. 
           44 —Stator that includes coils and ferromagnetic solid or laminated core, rotary slotless electrical machine. 
           46 —Coils, rotary slotless electrical machine. 
           48 —Ferromagnetic solid or laminated core, rotary slotless electrical machine. 
           50 —Rotor, rotary slotless electrical machine. 
           52 —Bushing, rotary slotless electrical machine. 
           54 —Magnets, rotary slotless electrical machine. 
           56 —Stator that includes coils and mixed core, rotary slotless electrical machine. 
           58 —Mixed core, rotary slotless electrical machine. 
           60  and  64 —Ferromagnetic (oriented or non-oriented) laminations, rotary slotless electrical machine. 
           62  and  66 —Non-ferromagnetic laminations, rotary slotless electrical machine. 
           68 —Radial mixed core, rotary slotless electrical machine. 
           70 —Stator that includes coils and radial mixed core, rotary slotless electrical machine. 
           72 —Random mixed core, rotary slotless electrical machine. 
           74 —Stator that includes coils and random mixed core, rotary slotless electrical machine. 
           75 —Forcer that includes coils and ferromagnetic solid or laminated core, linear tube slotless electrical machine (internal magnets). 
           76 —Coils, linear tube slotless electrical machine (internal magnets). 
           78 —Ferromagnetic solid or laminated core, linear tube slotless electrical machine (internal magnets). 
           80 —Magnet track, linear tube slotless electrical machine (internal magnets). 
           82 —Tube, linear tube slotless electrical machine (internal magnets). 
           84 —Magnets, linear tube slotless electrical machine (internal magnets). 
           86 —Forcer that includes coils and mixed core, linear tube slotless electrical machine (internal magnets). 
           88 —Mixed core, linear tube slotless electrical machine (internal magnets). 
           90  and  94 —Ferromagnetic (oriented or non-oriented) laminations, linear tube slotless electrical machine (internal magnets). 
           92  and  96 —Non-ferromagnetic laminations, linear tube slotless electrical machine (internal magnets). 
           98 —Radial mixed core, linear tube slotless electrical machine (internal magnets). 
           100 —Forcer that includes coils and radial mixed core, linear tube slotless electrical machine (internal magnets). 
           102 —Random mixed core, linear tube slotless electrical machine (internal magnets). 
           104 —Forcer that includes coils and random mixed core, linear tube slotless electrical machine (internal magnets). 
           106 —Forcer that includes coils and ferromagnetic solid or laminated core, linear tube slotless electrical machine (external magnets). 
           108 —Coils, linear tube slotless electrical machine (external magnets). 
           110 —Ferromagnetic solid or laminated core, linear tube slotless electrical machine (external magnets). 
           112 —Magnet track, linear tube slotless electrical machine (external magnets). 
           114 —Tube, linear tube slotless electrical machine (external magnets). 
           116 —Magnets, linear tube slotless electrical machine (external magnets). 
           118 —Forcer that includes coils and mixed core, linear tube slotless electrical machine (external magnets). 
           120 —Mixed core, linear tube slotless electrical machine (external magnets). 
           122  and  126 —Ferromagnetic (oriented or non-oriented) laminations, linear tube slotless electrical machine (external magnets). 
           124  and  128 —Non-ferromagnetic laminations, linear tube slotless electrical machine (external magnets). 
           130 —Radial mixed core, linear tube slotless electrical machine (external magnets). 
           132 —Forcer that includes coils and radial mixed core, linear tube slotless electrical machine (external magnets). 
           134 —Random mixed core, linear tube slotless electrical machine (external magnets). 
           136 —Forcer that includes coils and random mixed core, linear tube slotless electrical machine (external magnets). 
       
     
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0088]    Linear Flat Slotless Electrical Machine with Mixed Core. 
         [0089]    Linear flat slotless electrical machine with forcer that includes coils and ferromagnetic solid or laminated core for coils mounting is shown on  FIG. 1 . Forcer  10  consists of coils  12  encapsulated in epoxy  14  and ferromagnetic core  16 . Magnet track  18  consists of magnetic plate  20  and magnets  22 . 
         [0090]    The invented linear flat slotless electrical machine construction includes forcer  24  consisted of coils  12  encapsulated in epoxy  14 , and mixed ferromagnetic/non-ferromagnetic core  26  ( FIG. 2 ). The mixed core replaces conventional ferromagnetic core  16 . In the invented electrical machine the attraction and togging force is reduced. 
         [0091]    The mixed core  26  for linear flat slotless electrical machine is shown on  FIG. 3 . It is made of ferromagnetic (oriented or non-oriented) laminations  28  and non-ferromagnetic laminations  30 . Ferromagnetic and non-ferromagnetic laminations alternate along the core width. 
         [0092]    The mixed core can also be made of ferromagnetic laminations  36  and non-ferromagnetic laminations  38  that alternate along the core height. The construction of height mixed core  32  is shown on  FIG. 4 . The invented linear flat slotless electrical Machine construction that includes forcer  34  with height mixed core  32  is shown on  FIG. 5 . 
         [0093]    The mixed core can also be made of ferromagnetic laminations  36  and non-ferromagnetic laminations  30  and  38  that alternate both along the core height and along the core width. The construction of random mixed core  40  is shown on  FIG. 6 . The invented linear flat slotless electrical machine construction that includes forcer  42  with random mixed core  40  is shown on  FIG. 7 . 
         [0094]    The exact dimensions, mutual position and quantity of ferromagnetic laminations  28  and  36  and non-ferromagnetic laminations  30  and  38  for any type of mixed core depend on electromechanical design and are subject for optimization. 
         [0000]    Rotary Slotless Electrical Machine with Mixed Core. 
         [0095]    Rotary slotless electrical machine with stator that includes coils and ferromagnetic solid or laminated core for coils mounting is shown on  FIG. 8 . Stator  44  consists of coils  46  encapsulated in epoxy  14  and ferromagnetic core  48 . Rotor  50  consists of bushing  52  and magnets  54 . 
         [0096]    The invented rotary slotless electrical machine construction includes stator  56  consisted of coils  46  encapsulated in epoxy  14 , and mixed ferromagnetic/non-ferromagnetic core  58  ( FIG. 9 ). The mixed core replaces conventional ferromagnetic core  48 . In the invented electrical machine the attraction and cogging force is reduced. 
         [0097]    The mixed core  58  for rotary slotless electrical machine is shown on  FIG. 10 . It is made of ferromagnetic (oriented or non-oriented) laminations  60  and non-ferromagnetic laminations  62 . Ferromagnetic and non-ferromagnetic laminations alternate along the core length. 
         [0098]    The mixed core can also be made of ferromagnetic laminations  64  and non-ferromagnetic laminations  66  that alternate along the core radius. The construction of radial mixed core  68  is shown on  FIG. 11 . The invented rotary slotless electrical machine construction that includes stator  70  with radial mixed core  68  is shown on  FIG. 12 . 
         [0099]    The mixed core can also be made of ferromagnetic laminations  64  and non-ferromagnetic laminations  62  and  66  that alternate both along the core length and along the core radius. The construction of random mixed core  72  is shown on  FIG. 13 . The invented rotary slotless electrical machine construction that includes stator  74  with random mixed core  72  is shown on  FIG. 14 . 
         [0100]    The exact dimensions, mutual position and quantity of ferromagnetic laminations  60  and  64  and non-ferromagnetic laminations  62  and  66  for any type of mixed core depend on electromechanical design and are subject for optimization. 
         [0000]    Linear Tube Slotless Electrical Machine (Internal Magnets) with Mixed Core. 
         [0101]    Linear tube slotless electrical machine (internal magnets) with forcer that includes coils and ferromagnetic solid or laminated core is shown on  FIG. 15 . Forcer  75  consists of coils  76  and ferromagnetic core  78 . Magnet track  80  consists of tube  82  and magnets  84 . 
         [0102]    The invented linear tube slotless electrical machine (internal magnets) construction includes forcer  86  consisted of coils  76  and mixed ferromagnetic/non-ferromagnetic core  88  ( FIG. 16 ). The mixed core replaces conventional ferromagnetic core  78 . In the invented electrical machine the attraction and cogging force is reduced. 
         [0103]    The mixed core  88  for linear tube slotless electrical machine (internal magnets) is shown on  FIG. 17 . It is made of ferromagnetic (oriented or non-oriented) laminations  90  and non-ferromagnetic laminations  92 . Ferromagnetic and non-ferromagnetic laminations alternate along the core arc. 
         [0104]    The mixed core can also be made of ferromagnetic laminations  94  and non-ferromagnetic laminations  96  that alternate along the core radius. The construction of radial mixed core  98  is shown on  FIG. 18 . The invented linear tube slotless electrical machine (internal magnets) construction that includes forcer  100  with radial mixed core  98  is shown on  FIG. 19 . 
         [0105]    The mixed core can also be made of ferromagnetic laminations  94  and non-ferromagnetic laminations  92  and  96  that alternate both along the core arc and along the core radius. The construction of random mixed core  102  is shown on  FIG. 20 . The invented linear tube slotless electrical machine (internal magnets) construction that includes forcer  104  with random mixed core  102  is shown on  FIG. 21 . 
         [0106]    The exact dimensions, mutual position and quantity of ferromagnetic laminations  90  and  94  and non-ferromagnetic laminations  92  and  96  for any type of mixed core depend on electromechanical design and are subject for optimization. 
         [0000]    Linear Tube Slotless Electrical Machine (External Magnets) with Mixed Core. 
         [0107]    Linear tube slotless electrical machine (external magnets) with forcer that includes coils and ferromagnetic solid or laminated core is shown on  FIG. 22 . Forcer  106  includes coils  108  and ferromagnetic core  110 . Magnet track  112  consists of tube  114  and magnets  116 . 
         [0108]    The invented linear tube slotless electrical machine (external magnets) construction includes forcer  118  consisted of coils  108  and mixed ferromagnetic/non-ferromagnetic core  120  ( FIG. 23 ). The mixed core replaces conventional ferromagnetic core  110 . In the invented electrical machine the attraction and cogging force is reduced. 
         [0109]    The mixed core  120  for linear tube slotless electrical machine (external magnets) is shown on  FIG. 24 . It is made of ferromagnetic (oriented or non-oriented) laminations  122  and non-ferromagnetic laminations  124 . Ferromagnetic and non-ferromagnetic laminations alternate along the core arc. 
         [0110]    The mixed core can also be made of ferromagnetic laminations  126  and non-ferromagnetic laminations  128  that alternate along the core radius. The construction of radial mixed core  130  is shown on  FIG. 25 . The invented linear tube slotless electrical machine (external magnets) construction that includes forcer  132  with radial mixed core  130  is shown on  FIG. 26 . 
         [0111]    The mixed core can also be made of ferromagnetic laminations  126  and non-ferromagnetic laminations  124  and  128  that alternate both along the core arc and along the core radius. The construction of random mixed core  134  is shown on  FIG. 27 . The invented linear tube slotless electrical machine (external magnets) construction that includes forcer  136  with random mixed core  134  is shown on  FIG. 28 . 
         [0112]    The exact dimensions, mutual position and quantity of ferromagnetic laminations  122  and  126  and non-ferromagnetic laminations  124  and  128  for any type of mixed core depend on electromechanical design and are subject for optimization.