Patent Publication Number: US-2003234590-A1

Title: Magnetic motor apparatus and method

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] This invention relates to the field of motor or prime mover structures wherein movement of a movable member results from the repulsion of magnetic fields that are carried by the movable member and magnetic fields that are carried by a stationary member, and more specifically, to a machine or mechanism that transforms magnetic energy into mechanical energy.  
       [0003] 2. Description of the Related Art  
       [0004] The present invention provides a family of new, unusual and unobvious magnetic motors.  
       [0005] Magnetic motors are known in the art For example. U.S. Pat. No. 6,323,572 to Kinosihita provides a magnetic-type electric motor and generator. FIGS. 2A-2F of this patent show six embodiments of an outer rotor magnet-type generator having a number of division iron cores and a number of radially-extending magnets, whereas FIGS. 3A-3F of this patent show six embodiments of an inner rotor magnet-type generator that has a reverse structure to that shown in FIGS. 2A-2F.  
       SUMMARY OF THE INVENTION  
       [0006] While both electromagnets and permanent magnets can be used separately or concurrently within the spirit and scope of this invention, preferred embodiments of the present invention make use of powerful permanent magnets, and preferably permanent magnets that include neodymium (Nd).  
       [0007] Electromagnets, permanent magnets, or a combination thereof, can be used in accordance with the present invention to generate magnetic fields that extend external to the magnets. Such an external magnetic field (H) is a vector quantity that is measured in amperes per meter (A/m) in the KMS system, or in Oersteds (Oe) in the CGS system.  
       [0008] Permanent magnets of the preferred neodymium-type are known; for example, Nd/Fe/B (neodymium/iron/boron) magnets are known. It is also known that neodymium magnets have been used in the voice coil actuators of hard disk drives.  
       [0009] The present invention makes use of magnetic flux shields or magnetic flux barriers having a high magnetic permeability.  
       [0010] It is known that high nickel, magnetically soft alloys have been used to provide magnetic shielding for a variety of electronic devices An alloy of this type is mumetal; for example, a Ni80/Fe20 alloy or a Ni77/Fe14/Cu5/Mo4 alloy. Mumetal is known to provide ultra high magnetic permeability, for example as high as 1,000,000+ gauss/oersted, whereas the permeability of air is known to be about 1 gauss/oersted  
       [0011] The present invention makes use of the fact that when a magnetic field (H) emanates from a magnet and then permeates through the cross-sectional area of a medium such as a magnetic flux shield or flux barrier of the present invention, the magnetic field or magnetic flux converts to magnetic flux density (B) as a function of the permeability of the magnetic flux shield or flux barrier wherein the value B increases as a direct function of the permeability of the material that is used to make the magnetic flux shield or flux barrier.  
       [0012] In motors constructed and arranged in accordance with the present invention, a rotor and a stator are separated by an air gap. The rotor presents a plurality of magnetic flux windows of a given magnetic polarity to the air gap, and the stator provides a different number of magnetic flux windows of the given magnetic polarity to the air gap. The term “given magnetic polarity” as used herein can mean either a north magnetic pole or a south magnetic pole.  
       [0013] The rotor carries a number of equally spaced bar-type magnets, each magnet of which presents a magnetic pole of the given polarity to the air gap, for example, a plurality of equally spaced north magnetic poles are presented to one side of the air gap.  
       [0014] The stator carries a different number of equally spaced bar-type magnets, each magnet of which presents a north magnetic pole the other side of the air gap.  
       [0015] Each of the rotor and stator carries a number of magnetic flux shields that are made of a material having a high magnetic permeability, a non-limiting example being mumetal. These flux shields are placed on the rotor and on the stator such that the rotor presents a number of equally spaced north magnetic flux windows to the air gap, and such that the stator presents a different number of equally spaced north magnetic flux windows to the air gap.  
       [0016] In any position of the rotor, at least one rotor flux window interfaces with at least one stator flux window to a greater extent than any other combination of flux windows interact. This causes the rotor to be magnetically repelled from the stator. As a result of rotor movement, a currently-open window pair closes as another window pair opens, to thereby effect continuous movement of the rotor. In order to stop the rotor, one or both of the rotor and stator flux shields (and preferably the stator flux shields) are moved so that at least one (and preferably all) of the flux window pairs is closed.  
       [0017] As a feature of the invention, a continuous or 360-degree flux shield can be inserted into the 360-degree air gap to stop rotation of the rotor 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
     [0018]FIG. 1 is a top view of a rotary motor constructed and arranged in accordance with the invention, wherein this embodiment of the invention includes a stator or stationary member that encircles a rotor or movable member, wherein the stator carries five permanent magnets that are 72-degrees spaced, and wherein the rotor carries four permanent magnets that are 90-degrees spaced.  
     [0019]FIG. 2 is a perspective view of the motor of FIG. 1 wherein it is shown that the FIG. 1 stator includes slots that enable adjustment of the mounting angle of the five permanent magnets that are carried by the stator.  
     [0020]FIG. 3 is an enlarged view of a currently-operative rotor magnet and stator magnet, and a force diagram showing the force vector that produces movement of the FIG. 1 rotor.  
     [0021]FIG. 4 is an exploded perspective view of a stator magnetic shielding collar and a rotor magnetic shielding collar that are used to control the magnetic flux that emanates from the five stator magnets and the four rotor magnets shown in FIG. 1.  
     [0022]FIG. 5 is a simplified view, similar to FIG. 2 that shows a cylindrical or 360-degree flux shield can be inserted into the circular air gap of the FIG. 1 motor in order to stop rotation of the rotor 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0023]FIG. 1 is a top view of a rotary motor  10  that is constructed and arranged in accordance with the invention.  
     [0024] While the spirit and scope of the invention provides that the motor rotor may either encircle the stator or that the motor stator may encircle the rotor, in the FIGS. 1, 2 and  4  embodiment of the invention, a circular and non-magnetic stator or stationary member  11  encircles a circular and nonmagnetic rotor or movable member  12  that rotates on an axis of rotation  13  By way of a non-limiting example, stator  11  and rotor  12  may be formed of aluminum.  
     [0025] Rotor  12  and stator  11  are separated by a circular or annular air gap  19  that is at all points equidistant from axis  13 . Air gap  19  provides a uniform separation between the two facing surfaces of rotor  12  and stator  11  throughout the entire 360-degrees of air gap  19 .  
     [0026] As best seen in FIG. 1, stator  11  carries five magnets  14 - 18  that are equally spaced circumferentially about axis  13  and that are equally spaced radially from axis  13 . Since this embodiment of the invention uses five stator magnets  14 - 18 , the magnets are circumferentially spaced at 72-degrees about axis  13 .  
     [0027] Also as best seen in FIG. 1, rotor  12  carries four magnets  20 - 23  that are equally spaced circumferentially about axis  13 , and that are equally-spaced radially from axis  13 . Since this embodiment of the invention uses four rotor magnets  20 - 23 , the magnets are circumferentially spaced at 90-degrees about axis  13 .  
     [0028] In more general terms and within the spirit and scope of this invention, an integer number X of equally-spaced magnets are provided on rotor  12 , each of these rotor magnets presenting a magnetic pole of a given polarity to air gap  19 . In the FIG. 1 and  2  embodiment of the invention, the integer number X is  4 , the equal circumferential spacing is  90 -degrees, and each rotor magnet presents a north magnetic pole to air gap  19 .  
     [0029] Also in more general terms, a different integer number Y of equally-spaced magnets are provided on stator  11 , each of these stator magnets presenting a magnetic pole of the given polarity to air gap  19 . In the FIGS. 1 and 2 embodiment of the invention, the integer number Y is 5, the equal circumferential spacing is 72-degrees, and each stator magnet presents a north magnetic pole to air gap  19 .  
     [0030] While the embodiment of the invention described herein utilizes five permanent rotor magnets  14 - 18  and four permanent stator magnets  20 - 23  it is within the spirit and scope of the invention to use electromagnets, permanent magnets, or a combination of electromagnets and permanent magnets, with permanent magnets being preferred for use at least on rotor  12  due to the added complexity of providing electrical current to a moving member.  
     [0031] When permanent magnets are selected for use in accordance with the invention, it is preferable that strong permanent magnets be used, for example, permanent magnets that contain neodymium of which neodymium/iron/boron permanent magnets are a non-limiting example  
     [0032] Again more generally, and within the spirit and scope of the invention, the number of equally-spaced magnets on rotor  12  can be said to equal X magnets, and the different number of equally-spaced magnets on stator  11  can be said to equal Y magnets, wherein the numbers X and Y are integers, wherein X is not divisible by Y, wherein Y is not divisible by X, and wherein the two numbers X and Y are not both divisible by any other common integer number By way of a non-limiting example, a ratio of the number of magnets on rotor  12  to the different number of magnets on stator  11  can be selected from a ratio group consisting of a 4-to-5 ratio, a 4-to-7 ratio and a 4-to-9 ratio.  
     [0033] In the relative positions of rotor  12  and stator  11  shown in FIG. 1. rotor magnet  20  is in general alignment with stator magnet  15  Stated another way, magnet  20  and magnet  15  comprise an operative magnet pair. As a result of the north magnetic pole repulsions of these magnets  20  and  15 , a force is imparted to rotor  12 , causing rotor  12  to move as is depicted by arrow  25 . In view of the 90-degree spacing of the four rotor magnets and the 72-degree spacing of the five stator magnets, movement  25  operates to reduce the repulsion force that is generated by a current magnet pair  15 ,  20  while at the same the time another magnet pair  14 ,  23  that is located in a direction that is opposite to direction  25  is brought into a state of magnetic field repulsion. thus continuing movement of rotor  12  in direction  25   
     [0034] This continuous rotational force is applied to rotor  12  as one magnet pair moves out of a repulsion state as a different magnet pair moves into a repulsion state.  
     [0035] The repulsion force that is applied to rotor  12  is enhanced by, tilting stator magnets  14 - 18  in the direction of rotor movement  25 , and by tilting rotor magnets  20 - 23  in an opposite direction to the direction of rotor movement  25 .  
     [0036] In accordance with a feature of the invention, FIG. 2 shows that stator  11  includes five slots  26  that enable individual adjustment of the mounting angle of the five magnets  14 - 18  that are carried by stator  11 .  
     [0037] The present invention provides a number of magnetic flux shields on both stator  11  and rotor  12  to enhance the switching of the rotor magnetic repulsion force between individual stator magnet and rotor magnet pairs These magnetic flux shields operate to maximize the rotational force and torque that is applied to rotor  12 .  
     [0038] Thus, as best shown in FIG. 1, stator  11  carries five equally-spaced (72-degree spacing) magnetic flux shields  31 - 35  having a high magnetic permeability, and rotor  12  carries four equally spaced (90-degree spacing) magnetic flux shields  36 - 39  having a high magnetic permeability A non-limiting example of a material for use in fabricating flux shields  31 - 39  is mumetal; i.e., a high nickel and magnetically soft alloy, examples of which include Ni80/Fe20 and Ni77/Fe14/Cu5/Mo4.  
     [0039] The arrangement of magnetic flux shields  31 - 39  about axis  13  is such that each rotor magnet and each stator magnet is provided with a north pole flux window at the location of air gap  19 . For example, reference numeral  45  in FIG. 1 identifies the stator flux window for stator magnet  14 , and reference numeral  46  in FIG. 1 identifies the rotor flux window for rotor magnet  21 . In a like manner, each rotor magnet and stator magnet is provided with its own individual north pole magnetic flux window.  
     [0040] As a result, stator  11  and rotor  12  each present a plurality of magnetic flux windows of a given magnetic polarity to air gap  19 , with stator  11  providing a different number of magnetic flux windows than does rotor  12   
     [0041] In the FIG. 1 and  2  embodiment of the invention, rotor  12  carries a number of equally spaced bar-type magnets, each magnet of which presents a north magnetic pole to one side of air gap  19 , whereas stator  11  carries a different number of equally-spaced bar-type magnets, each magnet of which presents a north magnetic pole the other side of air gap  19   
     [0042] Each of rotor  12  and stator  11  carries a number of magnetic flux shields that are made of a material having a high magnetic permeability, an example material being mumetal. These flux shields are placed on rotor  12  and stator  11  such that rotor  12  presents a number of equally spaced north magnetic pole flux windows to air gap  19 , and such that stator  11  presents a different number of equally spaced north magnetic pole flux windows to air gap  19 .  
     [0043] In any position of rotor  12 , at least one rotor flux window operatively interfaces with at least one stator flux window to thereby cause rotor  12  to be magnetically repelled from stator  11 . As a result of movement  25  of rotor  12 , a currently-open flux window pair closes, as another flux window pair opens, to thereby effect a relatively continuous movement of rotor  12   
     [0044]FIG. 3 is an enlarged view of the currently operative rotor magnet/stator magnet pair  20 / 14  that is shown in FIG. 1. Line  50  of FIG. 3 is a tangent to the centerline (not shown) of air gap  19  at a point  51  whereat a centerline  52  of rotor magnet  20  and stator magnet  14  intersects the centerline of air gap  19 .  
     [0045] While rotor magnet  20  and stator magnet  14  are shown as having a common centerline  52  and thus a common angle of tilt  53 , this need not be the case in accordance with the present invention. That is, the tilt angle of stator magnet  14  can be changed by the use of slots  26  shown in FIG. 2 wherein clamping means (not shown) is provided to hold each stator magnet  14 - 18  in an adjusted position.  
     [0046] By way of example only, angle of tilt  53  can be in a range of from about 0-degrees to about 45-degrees.  
     [0047] In FIG. 3, a force vector  55  represents the magnetic force of repulsion that is generated relative to stator  11  as the north magnetic poles of rotor magnet  20  and stator magnet  14  mutually repel each other. A component  56  of force vector  55  represents a resultant force that produces movement  25  of rotor  12 .  
     [0048] As the number of rotor magnets and stator magnets is increased, the rotational movement of rotor  12  becomes more uniform and, in fact, conventional means such as a flywheel can be used to provide a relatively constant speed of rotation of rotor  12 , if desired.  
     [0049] In order to stop the movement of rotor  12 , one or both of the rotor and stator flux shields (and preferably the stator flux shields  31 - 35 ) are moved so that at least one (and preferably all) of the flux window pairs are closed  
     [0050]FIG. 4 is an exploded perspective view of a stator magnetic flux shielding collar  60  and a rotor magnetic flux shielding collar  61  that are used to control the magnetic flux that emanates from the five stator magnets  14 - 18  and the four rotor magnets  20 - 23  shown in FIG. 1.  
     [0051] Each of these collars  60 ,  61  is formed of a material having a high magnetic permeability, each of these collars is formed as a circular cylinder about axis  13 , and each of these collars includes an open flux window whose shape corresponds generally to the shape of the north pole end of its respective magnet.  
     [0052] Thus, stator magnetic shielding collar  60  includes five, 72-degree spaced, open flux windows  45 ,  62 ,  63 ,  64 , and  65 , whereas rotor magnetic shielding collar  61  includes four, 90-degree spaced, open flux windows  66 ,  46 ,  67 , and  68 .  
     [0053] As shown in FIG. 4, stator flux window  45  is in radial alignment with rotor flux window  66 . Thus, flux window pair  45 ,  66  is the only open flux window pair. This relative position of stator magnetic shielding collar  60  and rotor magnetic shielding collar  61  allows the north pole of rotor magnet  20  to interact with the north pole of stator magnet  14  as above described.  
     [0054] In order to stop rotation of rotor  12 , at least one of the two magnetic shielding collars  60 ,  61  is rotated about axis  13  to a position where no open flux window pair exists. Without limitation thereto, stator magnetic shielding collar  60  is moved in the direction shown by arrow  69  in FIG. 4.  
     [0055]FIG. 5 shows another means by which the rotation of rotor  12  may be stopped. More specifically, FIG. 5 is a simplified view, similar to FIG. 2, that shows a cylindrical or 360-degree flux shield  50  that can be inserted downward into circular air gap  19  in order to stop rotation of rotor  12 .  
     [0056] By way of a non-limiting example, cylindrical mumetal shield  50  may be latched in the upward and inoperative position shown in FIG. 5 against the force of a spring (not shown) When it is desired to stop rotor  12  a release mechanism (not shown) can be activated to cause mumetal shield  50  to move downward as a result of the force of the spring as indicated by arrow  51 , and into air gap  10 . This position of mumetal shield  50  operates to totally interrupt the above-described magnetic repulsion forces that cause rotor  12  to move.  
     [0057] As an example of the utility of the FIG. 5 feature, an over-speed sensor (not shown) can be provided to release mumetal shield  50  should the speed of rotation of rotor  12  become excessive, or mumetal shield  50  may be manually released to protect individuals working on the motor and/or mechanisms being driven by rotor  12 .  
     [0058] While specific examples of magnetic flux shielding have been described, within the spirit and scope of this invention additional shielding means can be provided to isolate the various rotor magnets and stator magnets from each other, as may be needed or desired in any given rotor/stator configuration.  
     [0059] While the above description has provided that stator  11  encircle rotor  12 , the spirit and scope of the invention includes embodiments of the invention wherein the rotor encircles the stator.  
     [0060] While the above-detailed description relates to specific embodiments of the invention, it is not intended that this detailed description be taken as a limitation on the spirit and scope of the invention.