Abstract:
The invention provides electrical actuators with grooved table top or housing (grooved actuators). In the invented electrical actuators, the Eddy current losses in moving conductive part from stationary permanent magnets (or in stationary conductive part from moving magnets) are reduced due to grooves.

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 Electrical machines and Drives. For reduction of Eddy current losses the ceramic plate is used. The plate increase the distance between magnets 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 electrical machine 
           [0003]    FIG.  1 . 2 —Linear actuator with linear flat electrical machine and grooved table top 
           [0004]    FIG.  2 —Grooved table top for linear actuators with linear flat electrical machine. 
           [0005]    FIG.  3 . 1 —Linear actuator with linear tubular electrical machine 
           [0006]    FIG.  3 . 2 —Linear actuator with linear tubular electrical machine and grooved housing 
           [0007]    FIG.  4 —Grooved housing for linear actuators with linear tubular electrical machine. 
           [0008]    FIG.  5 . 1 —Rotary actuator with rotary radial (magnets inside) ironless electrical machine 
           [0009]    FIG.  5 . 2 —Rotary actuator with rotary radial (magnets inside) ironless electrical machine and grooved housing 
           [0010]    FIG.  6 —Grooved housing for rotary actuators with rotary radial (magnets inside) ironless electrical machine 
           [0011]    FIG.  7 . 1 —Rotary actuator with rotary radial (magnets outside) ironless electrical machine 
           [0012]    FIG.  7 . 2 —Rotary actuator with rotary radial (magnets outside) ironless electrical machine and grooved housing 
           [0013]    FIG.  8 —Grooved housing for rotary actuators with rotary radial (magnets outside) ironless electrical machine 
           [0014]    FIG.  9 . 1 —Rotary actuator with rotary axial ironless electrical machine 
           [0015]    FIG.  9 . 2 —Rotary actuator with rotary axial ironless electrical machine and grooved housing 
           [0016]    FIG.  10 —Grooved housing for rotary actuators with rotary axial ironless electrical machine 
       
    
    
     DRAWINGS—REFERENCE NUMERALS  
       [0017]      12 —forcer (linear flat actuator) 
         [0018]      14 —table top (linear flat actuator) 
         [0019]      16 —magnet track (linear flat actuator) 
         [0020]      22 —linear bearings (linear flat actuator) 
         [0021]      24 —actuator base (linear flat actuator) 
         [0022]      26 —grooved table top (linear flat actuator) 
         [0023]      28 —grooves (linear flat actuator) 
         [0024]      32 —forcer (linear tubular actuator) 
         [0025]      34 —actuator housing (linear tubular actuator) 
         [0026]      36 —magnet track (linear tubular actuator) 
         [0027]      38 —magnets (linear tubular actuator) 
         [0028]      40 —tube (linear tubular actuator) 
         [0029]      42 —linear bearings (linear tubular actuator) 
         [0030]      44 —grooved housing (linear tubular actuator) 
         [0031]      46 —grooves (linear tubular actuator) 
         [0032]      48 —stator (rotary actuator, radial, magnets inside) 
         [0033]      50 —rotor (rotary actuator, radial, magnets inside) 
         [0034]      52 —table top (rotary actuator, radial, magnets inside) 
         [0035]      54 —magnets (rotary actuator, radial, magnets inside) 
         [0036]      56 —bushing (rotary actuator, radial, magnets inside) 
         [0037]      58 —bearings (rotary actuator, radial, magnets inside) 
         [0038]      60 —coils (rotary actuator, radial) 
         [0039]      62 —epoxy 
         [0040]      64 —housing (rotary actuator, radial, magnets inside) 
         [0041]      66 —stator with grooved housing (rotary actuator, radial, magnets inside) 
         [0042]      68 —grooved housing (rotary actuator, radial, magnets inside) 
         [0043]      70 —grooves (rotary actuator, radial, magnets inside) 
         [0044]      72 —stator (rotary actuator, radial, magnets outside) 
         [0045]      74 —rotor (rotary actuator, radial, magnets outside) 
         [0046]      76 —table top (rotary actuator, radial, magnets outside) 
         [0047]      78 —magnets (rotary actuator, radial, magnets outside) 
         [0048]      80 —bushing (rotary actuator, radial, magnets outside) 
         [0049]      82 —bearings (rotary actuator, radial, magnets outside) 
         [0050]      83 —housing (rotary actuator, radial, magnets outside) 
         [0051]      84 —stator with grooved housing (rotary actuator, radial, magnets outside) 
         [0052]      86 —grooved housing (rotary actuator, radial, magnets outside) 
         [0053]      88 —grooves (rotary actuator, radial, magnets outside) 
         [0054]      90 —stator (rotary actuator, axial) 
         [0055]      92 —rotor (rotary actuator, axial) 
         [0056]      94 —table top (rotary actuator, axial) 
         [0057]      96 —magnets (rotary actuator, axial) 
         [0058]      98 —bearings (rotary actuator, axial) 
         [0059]      100 —coils (rotary actuator, axial) 
         [0060]      102 —housing (rotary actuator, axial) 
         [0061]      104 —stator with grooved housing (rotary actuator, axial) 
         [0062]      106 —grooved housing (rotary actuator, axial) 
         [0063]      108 —grooves (rotary actuator, axial) 
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0064]    Linear Actuator with Linear Flat Electrical Machine. 
         [0065]    Linear actuator with linear flat electrical 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 . 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. 
         [0066]    The construction of the invented linear electric actuator with linear flat electrical machine includes forcer  12  mounted to the grooved table top  26  ( FIG. 1.2 ). Grooves prevent Eddy current losses in the table top. 
         [0067]    The grooved table top  26  for linear actuator with linear flat electrical machine is shown on  FIG. 2 . It is made of solid non-ferromagnetic or ferromagnetic material or compound. Grooves  28  are made along the table top length (parallel to electrical machine moving direction) or other direction. The exact dimensions, direction and quantity of grooves depend on electromechanical design and are subject for optimization. 
         [0000]    Linear Actuator with Linear Tubular Electrical Machine. 
         [0068]    Linear actuator with linear tubular electrical machine is shown on  FIG. 3.1 . Actuator consists of forcer  32 , mounted to the actuator housing  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 housing. 
         [0069]    The construction of the invented linear electric actuator with linear tubular electrical machine includes forcer  32  mounted to the grooved actuator housing  44  ( FIG. 3.2 ). Grooves prevent Eddy current losses in the actuator housing. 
         [0070]    The grooved housing  44  for linear actuator with linear flat electrical machine is shown on  FIG. 4 . It is made of solid non-ferromagnetic or ferromagnetic material or compound. Grooves  46  are made along the housing length (parallel to electrical machine moving direction) or other direction. The exact dimensions, direction and quantity of grooves depend on electromechanical design and are subject for optimization. 
         [0000]    Rotary Actuator with Rotary Radial (Magnets Inside) Ironless Electrical Machine. 
         [0071]    Rotary actuator with rotary radial (magnets inside) ironless electrical machine is shown on  FIG. 5.1 . Actuator consists of stator  48  and rotor  50 , mounted to the table top  52 . Rotor consists of magnets  54  and bushing  56 . Table top is mounted to bearings  58 . Stator  48  consists of coils  60 , encapsulated in epoxy  62  and mounted to the housing  64  (usually made of conductive material, for example, aluminum). During machine moving the Eddy current losses will occur in the housing. 
         [0072]    The construction of the invented rotary electric actuator with rotary radial (magnets inside) ironless electrical machine includes stator  66  that consists of coils  60 , encapsulated in epoxy  62  and mounted to the grooved housing  68  ( FIG. 5.2 ). Grooves prevent Eddy current losses in the housing. 
         [0073]    The grooved housing  68  for rotary actuator with rotary radial (magnets inside) ironless electrical machine is shown on  FIG. 6 . It is made of solid non-ferromagnetic or ferromagnetic material or compound. 
         [0074]    Grooves  70  are made perpendicular the rotation axis (parallel to electrical machine rotation), corkscrew direction, spiral direction or other direction. The exact dimensions, direction and quantity of grooves depend on electromechanical design and are subject for optimization. 
         [0000]    Rotary Actuator with Rotary Radial (Magnets Outside) Ironless Electrical Machine. 
         [0075]    Rotary actuator with rotary radial (magnets outside) ironless electrical machine is shown on  FIG. 7.1 . Actuator consists of stator  72  and rotor  74 , mounted to the table top  76 . Rotor consists of magnets  78  and bushing  80 . Table top is mounted to bearings  82 . Stator  72  consists of coils  60 , encapsulated in epoxy  62  and mounted to the housing  83  (usually made of conductive material, for example, aluminum). During machine moving the Eddy current losses will occur in the housing. 
         [0076]    The construction of the invented rotary electric actuator with rotary radial (magnets outside) ironless electrical machine includes stator  84  that consists of coils  60 , encapsulated in epoxy  62  and mounted to the grooved housing  86  ( FIG. 7.2 ). Grooves prevent Eddy current losses in the housing. 
         [0077]    The grooved housing  86  for rotary actuator with rotary radial (magnets outside) ironless electrical machine is shown on  FIG. 8 . It is made of solid non-ferromagnetic or ferromagnetic material or compound. 
         [0078]    Grooves  88  are made perpendicular the rotation axis (parallel to electrical machine rotation), corkscrew direction, spiral direction or other direction. The exact dimensions, direction and quantity of grooves depend on electromechanical design and are subject for optimization. 
         [0000]    Rotary Actuator with Rotary Axial Ironless Electrical Machine. 
         [0079]    Rotary actuator with rotary axial ironless electrical machine is shown on  FIG. 9.1 . Actuator consists of stator  90  and rotor  92  with magnets  96 , mounted to the table top  94 . Table top is mounted to bearings  98 . Stator  90  consists of coils  100 , mounted to the housing  102  (usually made of conductive material, for example, aluminum). During machine moving the Eddy current losses will occur in the housing. 
         [0080]    The construction of the invented rotary electric actuator with rotary axial ironless electrical machine includes stator  104  that consists of coils  100 , mounted to the grooved housing  106  ( FIG. 9.2 ). Grooves prevent Eddy current losses in the housing. 
         [0081]    The grooved housing  106  for rotary actuator with rotary axial ironless electrical machine is shown on  FIG. 10 . It is made of solid non-ferromagnetic or ferromagnetic material or compound. Grooves  108  are made parallel to electrical machine rotation, corkscrew direction, spiral direction or other direction. The exact dimensions, direction and quantity of grooves depend on electromechanical design and are subject for optimization.