Abstract:
The invention provides electrical actuators with reducer of Eddy current losses (Eddy current reducer) that improves the performance of actuator. In the electrical actuators, it greatly reduces the Eddy current losses in moving conductive part from stationary permanent magnets (or in stationary conductive part from moving magnets).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The problem of Eddy current losses in the electrical actuators is well known. Some way for solving the problem is described in “Design and Test of an Ironless, Three Degree-of-Freedom, Magnetically Levitated Linear Actuator with Moving Magnets” by J. V. Jansen, etc.—2005 IEEE International Conference on Electric Machines and Drives. For reduction of Eddy current losses the ceramic plate is used. The plate increase the distance between stationary and moving conductive part. This way is increasing actuator envelope. When using thick and strong magnets or go to high speed (several meter per second) the thickness of ceramic plate and therefore actuator envelope increase dramatically. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0002]    FIG.  1 . 1 —Linear actuator with linear flat electric machine 
           [0003]    FIG.  1 . 2 —Linear actuator with linear flat electric machine and. Eddy current reducer 
           [0004]    FIG.  2 —Eddy current reducer for linear actuators with linear flat electric machine and linear tube electric machine 
           [0005]    FIG.  3 . 1 —Linear actuator with linear tube electric machine 
           [0006]    FIG.  3 . 2 —Linear actuator with linear tube electric machine and Eddy current reducer 
           [0007]    FIG.  4 . 1 —Rotary actuator with rotary radial (magnets inside) ironless electric machine 
           [0008]    FIG.  4 . 2 —Rotary actuator with rotary radial (magnets inside) ironless electric machine and Eddy current reducer 
           [0009]    FIG.  5 —Eddy current reducer for rotary actuators with rotary radial ironless electric machine (magnets inside and outside) 
           [0010]    FIG.  6 . 1 —Rotary actuator with rotary radial (magnets outside) ironless electric machine 
           [0011]    FIG.  6 . 2 —Rotary actuator with rotary radial (magnets outside) ironless electric machine and Eddy current reducer 
           [0012]    FIG.  7 . 1 —Rotary actuator with rotary axial ironless electric machine 
           [0013]    FIG.  7 . 2 —Rotary actuator with rotary axial ironless electric machine and Eddy current reducer 
           [0014]    FIG.  8 —Eddy current reducer for rotary actuators with rotary axial ironless electric machine 
       
    
    
     DRAWINGS—REFERENCE NUMERALS 
       [0015]      12 —forcer (linear flat actuator) 
         [0016]      14 —table top (linear flat actuator) 
         [0017]      16 —magnet track (linear flat actuator) 
         [0018]      18 —magnetic plate (linear flat actuator) 
         [0019]      20 —magnets (linear flat actuator) 
         [0020]      22 —linear bearings (linear flat actuator) 
         [0021]      24 —actuator base (linear flat actuator) 
         [0022]      26 —Eddy current reducer (linear actuator) 
         [0023]      28 —pieces of ferromagnetic material or compound 
         [0024]      30 —non-magnetic spacers 
         [0025]      32 —forcer (linear tube actuator) 
         [0026]      34 —actuator base (linear tube actuator) 
         [0027]      36 —magnet track (linear tube actuator) 
         [0028]      38 —magnets (linear tube actuator) 
         [0029]      40 —tube (linear tube actuator) 
         [0030]      42 —linear bearings (linear tube actuator) 
         [0031]      44 —stator (rotary actuator, magnets inside) 
         [0032]      46 —actuator housing (rotary actuator, magnets inside) 
         [0033]      48 —rotor (rotary actuator, magnets inside) 
         [0034]      50 —magnets (rotary actuator, magnets inside) 
         [0035]      52 —table top (rotary actuator, magnets inside) 
         [0036]      54 —bearings (rotary actuator, magnets inside) 
         [0037]      56 —Eddy current reducer (rotary actuator with radial electric machine) 
         [0038]      58 —pieces of ferromagnetic material or compound 
         [0039]      60 —non-magnetic spacers 
         [0040]      62 —stator (rotary actuator, magnets outside) 
         [0041]      64 —actuator housing (rotary actuator, magnets outside) 
         [0042]      66 —rotor (rotary actuator, magnets outside) 
         [0043]      68 —magnets (rotary actuator, magnets outside) 
         [0044]      70 —table top (rotary actuator, magnets outside) 
         [0045]      72 —bearings (rotary actuator, magnets outside) 
         [0046]      74 —stator (rotary actuator, axial) 
         [0047]      76 —actuator base (rotary actuator, axial) 
         [0048]      78 —rotor (rotary actuator, axial) 
         [0049]      82 —table top (rotary actuator, axial) 
         [0050]      84 —bearings (rotary actuator, axial) 
         [0051]      86 —Eddy current reducer (rotary actuator, axial) 
         [0052]      88 —pieces of ferromagnetic material or compound 
         [0053]      90 —non-magnetic spacers 
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0054]    Linear Actuator with Linear Flat Electric Machine. 
         [0055]    Linear actuator with linear flat electric machine is shown on  FIG. 1.1 . Actuator consists of forcer  12 , mounted to the table top  14  (usually made of conductive material, for example, aluminum), and magnet track  16 . Magnet track  16  consists of magnetic plate  18  and magnets  20 . Table top is mounted to linear bearings  22 . Linear bearings and magnetic plate are installed on the actuator base  24 . During machine moving the Eddy current losses will occur in the table top. 
         [0056]    The construction of the invented linear electric actuator with linear flat electric machine includes forcer  12  mounted to the table top  14  with Eddy current reducer  26  ( FIG. 1.2 ). Reducer prevents Eddy current losses in the table top. 
         [0057]    The Eddy current reducer for linear actuator with linear flat electric machine is shown on  FIG. 2 . It is made of one or more assembled or solid pieces of oriented or non-oriented ferromagnetic material or compound (any shape, form, configuration or structure, solid or from parts, examples—sheets with or without holes, net, grid, bars, strips, etc.). Ferromagnetic pieces  28  are divided one from another by non-magnetic spacers  30 . The thickness of pieces is 0.010-1.0 mm each (or other depending on applications). The exact dimensions and quantity of pieces depend on electromechanical design and are subject for optimization. 
         [0058]    The invented design of linear actuator with linear flat electric machine not only reduces the module of magnetic field in conductive part but it also greatly reduces the normal component of magnetic field which creates Eddy currents (thereby the tangential component may increase but it do not create Eddy currents). Due to this feature, the very thin and magnetically saturated eddy current reducer has insignificant magnetic attraction and cogging. The Eddy current reducer finally reduces eddy current losses in table top  14 . 
         [0059]    Linear Actuator with Linear Tube Electric Machine. 
         [0060]    Linear actuator with linear tube electric machine is shown on  FIG. 3.1 . Actuator consists of forcer  32 , mounted to the actuator base  34  (usually made of conductive material, for example, aluminum), and magnet track  36 . Magnet track  36  consists of magnets  38  placed inside tube  40 . Magnet track is supported by linear bearings  42 . During machine moving the Eddy current losses will occur in the actuator base. 
         [0061]    The construction of the invented linear electric actuator with linear tube electric machine includes forcer  32  mounted to the actuator base  34  with Eddy current reducer  26  ( FIG. 3.2 ). Reducer prevents Eddy current losses in the actuator base. 
         [0062]    The Eddy current reducer for linear actuator with linear tube electric machine is shown on  FIG. 2 . It is made of one or more assembled or solid pieces of oriented or non-oriented ferromagnetic material or compound (any shape, form, configuration or structure, solid or from parts, examples—sheets with or without holes, net, grid, bars, strips, etc.). Ferromagnetic pieces  28  are divided one from another by non-magnetic spacers  30 . The thickness of pieces is 0.010-1.0 mm each (or other depending on applications). The exact dimensions and quantity of pieces depend on electromechanical design and are subject for optimization. 
         [0063]    The invented design of linear actuator with linear tube electric machine not only reduces the module of magnetic field in conductive part but it also greatly reduces the normal component of magnetic field which creates Eddy currents (thereby the tangential component may increase but it do not create Eddy currents). The Eddy current reducer finally reduces eddy current losses in actuator base  34 . 
         [0064]    Rotary Actuator with Rotary Radial (Magnets Inside) Ironless Electric Machine. 
         [0065]    Rotary actuator with rotary radial (magnets inside) ironless electric machine is shown on  FIG. 4.1 . Actuator consists of ironless stator  44 , mounted to the actuator housing  46  (usually made of conductive material, for example, aluminum), and rotor  48  with magnets  50 . Rotor is mounted to table top  52  that is supported by bearings  54 . During machine rotating the Eddy current losses will occur in the actuator housing. 
         [0066]    The construction of the invented rotary electric actuator with rotary radial (magnets inside) ironless electric machine includes ironless stator  44  mounted to the actuator housing  46  with Eddy current reducer  56  ( FIG. 4.2 ). Reducer prevents Eddy current losses in the actuator housing. 
         [0067]    The Eddy current reducer for rotary actuator with rotary radial (magnets inside) ironless electric machine is shown on  FIG. 5 . It is made of one or more assembled or solid pieces of oriented or non-oriented ferromagnetic material or compound (any shape, form, configuration or structure, solid or from parts, examples—sheets with or without holes, net, grid, bars, strips, etc.). Ferromagnetic pieces  58  are divided one from another by non-magnetic spacers  60 . The thickness of pieces is 0.010-.0 mm each (or other depending on applications). The exact dimensions and quantity of pieces depend on electromechanical design and are subject for optimization. 
         [0068]    The invented design of rotary actuator with rotary radial (magnets inside) ironless electric machine not only reduces the module of magnetic field in conductive part but it also greatly reduces the normal component of magnetic field which creates Eddy currents (thereby the tangential component may increase but it do not create Eddy currents). The Eddy current reducer finally reduces eddy current losses in actuator housing  46 . 
         [0069]    Rotary Actuator with Rotary Radial (Magnets Outside) Ironless Electric Machine. 
         [0070]    Rotary actuator with rotary radial (magnets outside) ironless electric machine is shown on  FIG. 6.1 . Actuator consists of ironless stator  62 , mounted to the actuator housing  64  (usually made of conductive material, for example, aluminum), and rotor  66  with magnets  68 . Rotor is mounted to table top  70  that is supported by bearings  72 . During machine rotating the Eddy current losses will occur in the actuator housing. 
         [0071]    The construction of the invented rotary electric actuator with rotary radial (magnets outside) ironless electric machine includes ironless stator  62  mounted to the actuator housing  64  with Eddy current reducer  56  ( FIG. 6.2 ). Reducer prevents Eddy current losses in the actuator housing. 
         [0072]    The Eddy current reducer losses for rotary actuator with rotary radial (magnets outside) ironless electric machine is shown on  FIG. 5 . It is made of one or more assembled or solid pieces of oriented or non-oriented ferromagnetic material or compound (any shape, form, configuration or structure, solid or from parts, examples—sheets with or without holes, net, grid, bars, strips, etc.). Ferromagnetic pieces  58  are divided one from another by non-magnetic spacers  60 . The thickness of pieces is 0.010-1.0 mm each (or other depending on applications). The exact dimensions and quantity of pieces depend on electromechanical design and are subject for optimization. 
         [0073]    The invented design of rotary actuator with rotary radial (magnets outside) ironless electric machine not only reduces the module of magnetic field in conductive part but it also greatly reduces the normal component of magnetic field which creates Eddy currents (thereby the tangential component may increase but it do not create Eddy currents). The Eddy current reducer finally reduces eddy current losses in actuator housing  64 . 
         [0074]    Rotary Actuator with Rotary Axial Ironless Electric Machine. 
         [0075]    Rotary actuator with rotary axial ironless electric machine is shown on  FIG. 7.1 . Actuator consists of ironless stator  74 , mounted to the actuator housing  76  (usually made of conductive material, for example, aluminum), and rotor  78 . Rotor is mounted to table top  82  that is supported by bearings  84 . During machine rotating the Eddy current losses will occur in the actuator housing. 
         [0076]    The construction of the invented rotary electric actuator with rotary axial ironless electric machine includes ironless stator  74  mounted to the actuator housing  76  with Eddy current reducer  86  ( FIG. 7.2 ). Reducer prevents Eddy current losses in the actuator housing. 
         [0077]    The Eddy current reducer for rotary actuator with rotary axial electric machine is shown on  FIG. 8 . It is made of one or more assembled or solid pieces of oriented or non-oriented ferromagnetic material or compound (any shape, form, configuration or structure, solid or from parts, examples—sheets with or without holes, net, grid, bars, strips, etc.). Ferromagnetic pieces  88  are divided one from another by non-magnetic spacers  90 . The thickness of pieces is 0.010-1.0 mm each (or other depending on applications). The exact dimensions and quantity of pieces depend on electromechanical design and are subject for optimization. 
         [0078]    The invented design of rotary actuator with rotary axial ironless electric machine not only reduces the module of magnetic field in conductive part but it also greatly reduces the normal component of magnetic field which creates Eddy currents (thereby the tangential component may increase but it do not create Eddy currents). The Eddy current reducer finally reduces eddy current losses in actuator base  76 .