Abstract:
A balanced magnetic rotor assembly is disclosed. The balanced rotor assembly including a driver rotor assembly having a first driver rotor assembly and a second driver rotor assembly arranged about a rotational axis and being spaced apart from each other a distance along the rotational axis, and a load rotor being arranged about the rotational axis and arranged between the first driver rotor and the second driver rotor.

Description:
BACKGROUND 
       [0001]    Technical Field 
         [0002]    The present disclosure relates to apparatuses, systems, and methods for magnetic couplings and drives and, more particularly, to magnetically balanced magnetic couplings and drives. 
         [0003]    Description of the Related Art 
         [0004]    Magnetic drive systems operate by transmitting torque from a motor to a load across an air gap. There is no mechanical connection between the driving and driven sides of the equipment. Torque is created by the interaction of powerful magnets on one side of the drive with induced magnetic fields on the other side. 
         [0005]    Magnetic drive systems may include a magnetic rotor assembly at the driven end and a conductor rotor assembly at the driver end. The conductor rotor assembly includes a rotor made of a conductive material, such as aluminum, copper, or brass. In some magnetic drive systems, such as the adjustable speed drive systems, the magnetic drive system also includes actuation components, which control the air gap spacing between the magnet rotors and the conductor rotors. 
         [0006]    Magnetic drive systems may also include a magnetic rotor assembly at the driven end and a magnetic rotor assembly at the driver end. In magnetic drive systems that include a magnetic rotor assembly at the driven end and a magnetic rotor assembly at the driver end, large axial forces are generated between the two magnetic rotor assemblies. The large axial forces are caused by the magnetic attraction or repulsion forces between the two magnetic rotor assemblies. To support these large magnetic loads, large axial bearings and a sturdy axial support structure are used. 
       BRIEF SUMMARY 
       [0007]    A balanced magnetic rotor assembly is disclosed. The balanced magnetic rotor assembly may include a driver rotor assembly having a first driver rotor and a second driver rotor arranged about a rotational axis and being spaced apart from each other a distance along the rotational axis. The first driver rotor may include a first array of a first plurality of magnets coupled to a first plate, the first array of the first plurality of magnets arranged in a first plane that is perpendicular to the rotational axis of the driver rotor assembly, a first of the first plurality of magnets having a north pole face in a first direction and being arranged between a second and a third of the first plurality of magnets, the second and the third of the first plurality of magnets having a south pole face also in the first direction. The second driver rotor may include a second array of a second plurality of magnets coupled to a second plate, the second array of the second plurality of magnets arranged in a second plane that is perpendicular to the rotational axis of the driver rotor assembly and parallel to the first plane, a first of the second plurality of magnets having a south pole face in a second direction and being arranged between a second and a third of the second plurality of magnets, the second and the third of the second plurality of magnets having a north pole face also in the second direction. The balanced magnetic rotor assembly may also include a load rotor being arranged about the rotational axis and arranged between the first driver rotor and the second driver rotor, the load rotor including a body having a third array of a third plurality of magnets therein, the third array of the third plurality of magnets arranged in a third plane that is perpendicular to the rotational axis of the driver rotor assembly and parallel to the first and second planes, a first of the third plurality of magnets having a north pole face in the first direction and a south pole face in the second direction and being arranged between a second and a third of the third plurality of magnets, the second and the third of the third plurality of magnets each having a south pole face in the first direction and a north pole face in the second direction. 
         [0008]    Another balanced magnetic rotor assembly is disclosed and may include a driver rotor having a first body and a first array of a first plurality of magnets and a first ring magnet therein, the first array of the first plurality of magnets arranged in a first plane that is perpendicular to a rotational axis of the driver rotor, a first of the first plurality of magnets having a north pole face in a first direction and being arranged between a second and a third of the first plurality of magnets, the second and the third of the first plurality of magnets having a south pole face also in the first direction, the first ring magnet having a ring shape, the ring shape having a center that is on the rotational axis, the first ring magnet having a first magnetic having pole a first magnetic polarity in the first direction. The balanced magnetic rotor assembly may also include a load rotor assembly having a second body and a second array of a second plurality of magnets and a second ring magnet therein, the second array of the second plurality of magnets arranged in a second plane that is perpendicular to the rotational axis of the driver rotor, a first of the second plurality of magnets having a south pole face in a second direction, opposite the first direction and being arranged between a second and a third of the second plurality of magnets, the second and the third of the second plurality of magnets having a north pole face also in the second direction, the second ring magnet having a ring shape, the ring shape having a center that is on the rotational axis; the second ring magnet having a first magnetic pole having a the first magnetic polarity in the second direction. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]      FIG. 1A  is an isometric view of a three-rotor balanced magnetic rotor assembly illustrating a driver end, according to one or more embodiments disclosed herein. 
           [0010]      FIG. 1B  is an isometric view of a three-rotor balanced magnetic rotor assembly illustrating a load end, according to one or more embodiments disclosed herein. 
           [0011]      FIG. 2A  includes an exploded view of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0012]      FIG. 2B  is a side view of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0013]      FIG. 2C  is a cross-sectional view of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0014]      FIG. 3A  is an exploded view of a drive side magnetic rotor of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0015]      FIG. 3B  is a front side view of a drive side magnetic rotor of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0016]      FIG. 3C  is a back side view of a drive side magnetic rotor of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0017]      FIG. 3D  is a cross-sectional view of a drive side magnetic rotor of a three-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0018]      FIG. 4  is an isometric view of a two-rotor balanced magnetic rotor assembly, according to one or more embodiments disclosed herein. 
           [0019]      FIG. 5  is an isometric view of one magnetic rotor of the two-rotor balanced magnetic rotor shown in  FIG. 4 , according to one or more embodiments disclosed herein. 
           [0020]      FIG. 6  is an isometric view of another one of the magnetic rotors of the two-rotor balanced magnetic rotor shown in  FIG. 4 , according to one or more embodiments disclosed herein. 
           [0021]      FIG. 7  shows a perspective view of an arrangement of magnets in a three-rotor balanced magnet drive system. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The following detailed description is directed toward apparatuses, systems, and methods for use in connection with magnetic drive systems. The description and corresponding figures are intended to provide an individual of ordinary skill in the art with enough information to enable that individual to make and use embodiments of the invention. Such an individual, however, having read this entire detailed description and reviewed the figures, will appreciate that modifications can be made to the illustrated and described embodiments, and/or elements removed therefrom, without deviating from the spirit of the invention. It is intended that all such modifications and deviations fall within the scope of the invention, to the extent they are within the scope of the associated claims. 
         [0023]    Referring now to  FIGS. 1-3 , a three-rotor balanced magnetic rotor assembly  100  is described.  FIGS. 1-3  depicts the three-rotor balanced magnetic rotor assembly  100  and various views.  FIG. 1  (collectively including  FIGS. 1A and 1B ) shows the rotor assembly  100  in an assembled configuration.  FIG. 1A  shows the driver end  101  of the rotor assembly  100  and  FIG. 1B  shows the load end  103  of the rotor assembly  100 . The driver end  101  of the rotor assembly  100  may be the power input side of the rotor assembly  100 , while the load end  103  of the rotor assembly  100  may be the output side of the rotor assembly  100 . In some embodiments, a motor, such as an electric or gas powered motor, may be attached to the driver coupling  102  of the rotor assembly  100 , and a load, such as a fan or blower, a conveyor system, or other load, may be attached to the load coupling  104  of the rotor assembly  100 . As described below, the rotor assembly  100  includes three rotors split between a load assembly  160  and a driver assembly  110 . The load assembly  160  includes the load coupling  104 , that includes a hub and shrink disk, and the load rotor  170 , and the driver assembly  110  includes the driver coupling  102  and two driver rotors  120 ,  130 . As best shown in  FIGS. 1 and 2  (collectively including  FIGS. 2A-2C ), the load rotor  170  is located between the two drive rotors  120 ,  130 . 
         [0024]    The transfer of rotational energy from the driver rotor assembly  110  to the load rotor assembly  160  occurs through the interaction of magnetic fields. In particular, the rotational energy is transmitted through the magnetic attractive forces between the magnets  172  in the load rotor  170  and the magnets  122 ,  132  in the driver rotors  120 ,  130 . As the driver rotors  120 ,  130  rotate, the magnetic attractive forces between the magnets  122 ,  132  in the driver rotors  120 ,  130 , pull the magnets  172  of the load rotor  170 , causing the load rotor  170  to also rotate. The magnetic forces between the rotors  120 ,  130 ,  170  are in both an axial direction, in which each of the driver rotors pulls the load rotor axially; and radially, in which, as the driver rotors  120 ,  130  rotate, the magnets  122 ,  132  of the driver rotors  120 ,  130  also induce a circumferential, rotational, load on the magnets  172  of the load rotor  170 . The radial forces between the rotors  120 ,  130 ,  170  transfer the rotational energy from the driver rotors  120 ,  130  to the load rotor  170 . The axial loads generally do not contribute to the transfer of rotational energy between the rotors  120 ,  130 ,  170 . 
         [0025]    The axial loads in the three-rotor balanced magnetic rotor assembly  100  are balanced, such that the overall axial loads may be reduced. For example, as compared to an unbalanced magnetic rotor assembly, a balanced magnetic rotor assembly may use smaller axial thrust bearings and a smaller axial support structure. 
         [0026]    In the embodiment shown in  FIGS. 1-3 , magnetic axial forces imparted on the load rotor  170  by the driver rotors  120 ,  130  may be balanced through an arrangement of the magnets  122 ,  132 ,  172  of the rotors  120 ,  130 ,  170 . In particular, the polarity of the magnets  122 ,  132 ,  172  within the rotors  120 ,  130 ,  170  are arranged such that the axial magnetic forces between the rotor  120  and the rotor  170  are balanced with the axial magnetic forces between the rotor  170  and the rotor  130 . By balancing the forces between the rotors  120 ,  130 ,  170 , the axial bearings and the axial support structure that supports and aligns the rotor assembly  100  may be reduced or smaller as compared to an unbalanced rotor assembly. 
         [0027]    In some embodiments, each of the magnets  122 ,  132 ,  172  may be a set of magnets having their magnetic poles facing the same direction, each adjacent set of magnets having opposite facing magnetic poles. 
         [0028]      FIG. 7  shows an embodiment of an arrangement of magnets  122   a ,  132   a ,  172   a  in, for example, the three-rotor balanced magnetic rotor assembly  100 . In such an embodiment, the magnet  122   a , which may be located in the driver rotor  120 , has its magnetic south pole face  123  facing a magnetic north pole face  171  of the magnet  172   a , which would be located in the load rotor  170 . The magnet  172   a  has its south pole surface  173  facing a north pole surface  131  of the magnet  132   a  of the driver rotor  130 . The south pole surface  133  of magnet  132   a  is opposite the north pole surface  131 . This arrangement creates an attractive force between the magnet  122   a  and the magnet  172   a  that is balanced by the attractive force between the magnet  172   a  and the magnet  132   a.    
         [0029]    As shown, for example, in  FIG. 3  (collectively including  FIGS. 3A-3D ), the polarity of the magnets facing a side of a given rotor can alternate between a north pole facing surface and a south pole facing surface. In such an arrangement, as the driver rotors  120 ,  130  rotate relative to the load rotor  170 , for example, during acceleration of the rotors, the forces between the driver rotors  120 ,  130  and the load rotor  170  alternate between a balanced attractive force and a balanced repulsive force. When the speed of the load rotor  170  matches the speed of the driver rotors  120 ,  130 , the magnets may align an arrangement that balances attractive forces between the driver rotors  120 ,  130  and the load rotor  170 . 
         [0030]      FIG. 2A  shows an exploded view of the three-rotor balanced magnetic rotor assembly  100 . To assemble the magnetic rotor assembly  100 , the load rotor  170  is placed between the two driver rotors  120 ,  130 , and the two driver rotors  120 ,  130  are secured to each other via a plurality of spacer assemblies  140 , which may be fasteners. The spacer assemblies  140  may include a bolt  151 , a spacer  152  and a nut  153 , as shown in  FIG. 3 . The bolt  151 , the spacer  152 , and the nut  153  aid in maintaining a separation distance between the driver rotors  120 ,  130 . 
         [0031]    As shown in  FIG. 2 , for example, the driver coupling  102  is coupled to a back plate of one of the driver rotors  120 ,  130 . The driver coupling  120  may be secured to the back plate  126  of the driver rotor  120  with fasteners  144 . Similarly, the load coupling  104  is coupled to the load rotor  170  via fasteners  142 . In some embodiments, the driver coupling  102  and the load coupling  104  are shrink disk couplings, although other types of couplings may be used. 
         [0032]    The load rotor  170  includes a body  175 , which may be, for example, a frame. In some embodiments, the body  175  may include a plurality of cavities  176  configured to hold an array of magnets  172 . As shown in  FIG. 2 , the magnets may be in a circular array that is arranged around the rotational axis of the load rotor  170 . Although shown as rectangles in  FIG. 2 , the magnets  172 , and indeed, also the magnets  122 ,  132  of the driver rotors  120 ,  130 , may be rectangular in shape, pie shaped, wedge shaped, or other shape that facilitates the balancing of the axial magnetic forces between the load rotor  170  and the driver rotors  120 ,  130  and the transfer of energy between the load rotor  170  and the driver rotors  120 ,  130 . 
         [0033]      FIG. 3A  shows an exploded view of the driver rotor assembly  110 . As discussed above, the driver rotor assembly  110  includes two driver rotors  120 ,  130 . Each driver rotor  120 ,  130  may include an array of magnets  122 ,  132  mounted to a frame  126 ,  136 . The magnets  122 ,  132 , shown in  FIG. 3 , are arranged in an array that forms the shape of an annulus, but in other embodiments the magnets may be formed in other shapes. 
         [0034]    The magnets  122 ,  132  may be affixed to one of the back plates  126 ,  136  via epoxy, glue, an adhesive, or other material. In addition, the array of magnets  122 ,  132  may be held against one of the back plates via a cover, such as one of the covers  124 ,  134 . The covers  124 ,  134  may be coupled or otherwise secured to one of the back plates  126 ,  136  via one or more fasteners  148 . 
         [0035]      FIGS. 4-6  depict a two-rotor balanced magnetic rotor assembly  400 . Similar to the three-rotor balanced magnetic rotor assembly  200 , the rotor assembly  400  includes a load rotor assembly  420  at a driver rotor assembly  410 . The load rotor assembly  420  includes a single load rotor  422 , but unlike the driver rotor assembly  110 , the driver rotor assembly  410  of the two-rotor balanced magnetic rotor assembly  400  includes a single rotor  412 . Each of the rotors  410 ,  420  include an array of magnets  414 ,  424 . Similar to the array of magnets  122 ,  132 ,  172  in the rotor assembly  100 , the magnets  414 ,  424  may be arranged in a circular or annular array of alternating polarities, for example as shown in  FIG. 5 . Also similar to the rotor assembly  100  described above, the arrays of magnets  414 ,  424  transmit rotational energy between the driver rotor  410  and the load rotor  420 . The arrays of magnets  414 ,  424  and their magnetic fields also generate axial forces on the rotors  410 ,  420 . In particular, when the rotors  410 ,  420  are rotating at the same rate, the polarity of the magnets  414  in the driver rotor  410  are attracted to corresponding magnets  424  in the load rotor  420 . To counteract the attractive forces between the magnets  414  and  424 , each of the rotors  410 ,  420  include a ring or annular shaped magnet  416 ,  426 . 
         [0036]    The polarity of the ring-shaped magnets  416  is chosen in order to counteract the attractive axial forces between the array of magnets  414 ,  424 . For example, in the embodiment shown in  FIGS. 4 and 5 , the inward facing surface  416  of the ring magnet  412  has a polarity that matches the inward facing surface of the ring magnet in the rotor  420  such that the ring magnets repel each other with a force that counteracts the attractive forces between the array of magnets  414 ,  424 . 
         [0037]    The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.