Patent Abstract:
A component includes magnet elements adjoined to each other to form an arced segmented magnet section that is configured to fit in an a curved rotor slot gap of an electric machine. An electric machine that employs the component and method of assembly of the component are also disclosed. The present invention has been described in terms of specific embodiment(s), and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

Full Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to electric machines and more particularly to a segmented magnet component for use in an electric machine and methods of assembling the segmented magnet component and electric machine. 
     Manufacturing of permanent magnets (PM) for use in electric machines, such as interior permanent magnet (IPM) machines, typically requires a cost-intensive mold and sinter process. Additionally, in order to provide the various PM shapes for the various shapes and configurations of slots, the magnets must be cut or milled Often multiple shapes and sizes of magnets are required for a single model of IPM machine. The magnets, once manufactured, are placed or inserted into the various slots in the rotor laminations. For example, as shown in  FIG. 1 , what often occurs is standard magnet sizes  170  (e.g., rectangles) are placed in the rows  160  of voids  165  of a rotor lamination  150 . Often the magnets  170  end up inefficiently filling the spaces  165 . This inefficient and expensive process further results in undesirable empty spaces or voids remaining in the slots between the inserted magnets and the lamination of the rotor. This inefficiency and cost also creates a disincentive in manufacturing rotor laminations that have curved rows of curved voids due to the difficulty in efficiently filling the curved voids. 
     Accordingly, there is an ongoing need for improvement of current electric machine manufacturing technologies that address at least one of complexity, cost, efficiency, and/or performance. 
     BRIEF DESCRIPTION 
     The present invention overcomes at least some of the aforementioned drawbacks by providing improvements to electric machines, such as IPM machines, so the machines may be both manufactured more efficiently in addition to providing a more technically efficient electric machines. More specifically, the present invention is directed to a segmented magnet component for use in an electric machine and a method of assembling the component into the electric machine. In an embodiment, a vehicle, such as an underground mining vehicle, may employ compact traction motors that utilize aspects of the present invention. 
     Therefore, in accordance with one aspect of the invention, a component comprises a plurality of magnet elements adjoined to each other, thereby defining an arced segmented magnet section, wherein the arced segmented magnet section is configured to fit in an a curved rotor slot gap of an electric machine. 
     In accordance with another aspect of the invention, an electric machine comprises: a rotor core comprising a plurality of laminations; a stator configured with a plurality of stationary windings therein; a plurality of curved rotor slot gaps disposed within the plurality of rotor laminations; and a segmented magnet component disposed in each of the plurality of curved rotor slot gaps. 
     In accordance with another aspect of the invention, a method comprises: adjoining a plurality of magnetizable segments next to each other, thereby defining an arced segmented magnet section, wherein each of the plurality of magnetizable segments are a same size and shape; inserting said arced segmented magnet section into a curved rotor slot gap of an electric machine rotor lamination; and magnetizing the arced segmented magnet section. 
     Various other features and advantages of the present invention will be made apparent from the following detailed description and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a plan view of a portion of a rotor of the related art. 
         FIG. 2  is a plan view of a segmented magnet component and portion of a rotor according to an embodiment of the present invention. 
         FIG. 3  is a top perspective view of a segmented magnet component according to an embodiment of the present invention. 
         FIGS. 4A-4E  are plan views of various embodiments of a single segment of a segmented magnet component, according to various embodiments of the present invention. 
         FIG. 5  is a flowchart of a method of assembly, according to embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art with respect to the presently disclosed subject matter. The terms “first”, “second”, and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a”, “an”, and “the” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item, and the terms “front”, “back”, “bottom”, and/or “top”, unless otherwise noted, are used for convenience of description only, and are not limited to any one position or spatial orientation. 
     If ranges are disclosed, the endpoints of all ranges directed to the same component or property are inclusive and independently combinable (e.g., ranges of “up to about 25 wt. %,” is inclusive of the endpoints and all intermediate values of the ranges of “about 5 wt. % to about 25 wt. %,” etc.). The modified “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). Accordingly, the value modified by the term “about” is not necessarily limited only to the precise value specified. 
     Referring to  FIG. 2 , a plan view of a rotor structure component and portion of a rotor, according to an embodiment of the present invention, is depicted. The rotor component, or termed a segmented magnet component, or termed as component, is denoted by  10  and is shown in a portion of a electric machine  100 . The portion of the electric machine  100  shown is a portion of a rotor lamination  30 . As depicted, the portion of the electric machine  100  may comprise a portion of an interior permanent magnet (IPM) machine. 
     The rotor lamination  30  may comprise a plurality of rows of curved rotor slot gaps  32 . As shown, there are four (4) rotor slot gaps  32 , with the outermost curved rotor slot gap  32  being empty. The other three inward curved rotor slot gaps  32  each receive a curved rotor structure component  10 . The unique configuration of the elements  12  and components  10  result in a significantly smaller remaining space, or void  34  in the rotor slot gap  32  after placement of the component  10 . This smaller space, or void  34  between rotor slot gap  32 , component  10 , and lamination  30  ultimately leads to improved performance of the electric machine  100  (partially shown). 
     It should be noted that while the configuration shown in  FIG. 2  depicts four rows of rotor slot gaps  32  wherein three of the four rows of rotor slot gaps  32  are filled with components  10 , there are other embodiments and configurations possible. Clearly, other quantities of rows of rotor slot gaps  32  are possible. So too can other quantities, or ratios, of filling the rotor slot gaps  32  with components  10  be possible under aspects of the present invention. By non-limiting example, all of the rows of rotor slot gaps  32  may be filled with components  10 , just as only a single row of the rows of rotor slot gaps  32  may be filled with a component  10 . The fill (or non-fill) ratio of components  10  in (or not in) the rotor slot gaps  32  may be virtually any value. 
     Referring to  FIG. 3 , a perspective view of a portion of the rotor structure component, according to an embodiment of the present invention, is depicted. The component  10  is an arced magnetic segment comprised of a plurality of magnetizable elements, or elements,  12 . Each of the plurality of magnetizable elements  12  comprises an element  12  having a first end, or concave end,  14  and a second end, or convex end,  16 . As shown, each of the elements  12  may be the same size and shape. The plurality of elements  12  may be adjoined (e.g., placed, located, and/or connected) next to each other such that the first end  14  of a first element  12  is adjacent to the second end  16  of an adjacent second element  12 . In this manner, an arced segment component  10  can be constructed of virtually any length and/or curvature suitable to fit inside a curved rotor slot gap  32  of a rotor lamination  30  of a machine  100  (See e.g.,  FIG. 2 ). Advantageously, aspects of the present invention allow for an improved filling factor of the curved rotor slot gaps  32 . Further, aspects of the present invention allow for further capability and flexibility by constructing curved components  10  of virtually any angle that can readily fill any angle curved slot including curved slots that have curvature that changes over the length of the slot as well as uniform curvature. This may be achieved by the use of a magnetizable element  12  of a single shape and size. 
     The magnetizable elements  12  may comprise any suitable material including but not limited to, for example, Ferrite, Alnico, or rare earth metals, such as, NdFeB, Somarium-Cobalt, and the like. In certain embodiments, the magnetizable elements  12  may be adhered to each other via any suitable glue, adhesive, resin, and the like. Similarly, in other embodiments, the magnetizable elements  12  may be adjoined (but not adhered), to each other such that the magnetizable elements are dry fit, or friction fit, into the rotor slot gap(s)  32  (See e.g.,  FIG. 2 ). 
     Referring to  FIGS. 4A-4E , plan views of various embodiments of the magnetizable elements  12  are shown. As depicted, different shapes for the element  12  may be employed without departing from aspects of the present invention. Each magnetizable element  12  may comprise a first end  14  and a second end  16 . The magnetizable element  12  is configured in shape and size such that the first end  14  of a first element  12  is compatible with fitting with the adjoining second end  16  of an adjacent, second element  12 . In this manner, a component  10  (See e.g.,  FIGS. 2 and 3 ) may be constructed from a plurality of adjoined magnetizable elements  12 . 
     For example,  FIG. 4A  shows an embodiment of an element  12  having a concave first end  14  and a convex second end  16 , wherein the shape may be termed “half-mooned”.  FIG. 4B  shows an embodiment of an element  12  having a flat first end  14  and a slanted, or angled, second end  16 , wherein the shape may be termed “right trapezoid”.  FIG. 4C  shows an embodiment of an element  12  having both first end  14  and second end  16  that are slanted, wherein the shape may be termed “trapezoidal”. In some embodiments, the angles of the first end  14  and second end  16  need not match.  FIG. 4D  shows an embodiment of an element  12  having a first end  14  being angled concave and a second end  16  being angled convex, wherein the shape may be termed “chevron”.  FIG. 4E  shows two different elements  12   a ,  12   b  wherein the first element  12   a  is circular and the second element  12   b  that could be termed “double half-mooned” shape. The first element  12   a  has a first end  14  and a second end  16  that are both curved. Similarly, the second element  12   b  has a first end  14  and a second end  16  that are both convex. In this particular embodiment, it should be apparent that the two different shaped elements  12   a ,  12   b  may be placed adjoining each other, in an alternatingly pattern so that the first end  14  of the first (circular) element  12   a  is adjoined, or adjacent, to the second end  16  of the second element  12   b , such that a curved component  10  may be constructed. Clearly, other shapes and configurations are possible without departing from aspects of the present invention. 
     The embodiments depicted in  FIGS. 4A and 4E , for example, offer an advantage of providing the ability to readily construct segmented magnet components that are curved and can fit into curved slots of virtually any machine that has curved rotor slots (lamination or solid rotor core) from, in the case of the embodiment in  FIG. 4A , a single sized/shaped component  12 , and in the case of the embodiment in  FIG. 4E , merely two sized/shaped components  12   a ,  12   b.    
     Under aspects of the present invention, the components  10  and the electric machines  100  discussed herein may be used as a traction motor for virtually any vehicle. A vehicle support frame (not shown) may be connected to the one or more electric machine  100 . Suitable vehicles for use include, but are not limited to, an off-highway vehicle (OHV), a locomotive, a mining vehicle, electric-motorized railcar, automobiles, trucks, construction vehicles, agricultural vehicles, airport ground service vehicles, fork-lifts, non-tactical military vehicles, tactical military vehicles, golf carts, motorcycles, mopeds, all-terrain vehicles, and the like. 
     Note that while various embodiments discussed herein describe a rotor core lamination  30  (see e.g.,  FIG. 2 ), it should be noted that other types of electric machine  100  constructs may be used without departing from aspects of the present invention. For example, the rotor core may, instead of be constructed of a plurality of laminations  30 , be a solid rotor core (i.e., no laminations). In this type of solid rotor core embodiment, the magnetizable elements  12 , for example, would typically be substantially deeper than the magnetizable elements  12  depicted in  FIG. 3  for example. In this manner, the magnetizable elements  12  would have a length the same, or similar to, the length of the entire solid rotor core and/or the rotor slot gaps in the solid rotor core. 
     A flowchart depicting a method of assembly, according to aspects of the present invention, is depicted at  FIG. 5 . A method may comprise adjoining magnetizable segments to each other at  202 . The magnetizable segments may be all of uniform size and shape. The bonding thereby forms an arced section at  204 . Then at  206  the arced section is magnetized. At  208 , the arced section (now magnetized) is inserted into a curved rotor slot on a rotor lamination. Alternatively, as shown in the flowchart, after  204 , the arced section may be inserted into the curved rotor section on a rotor lamination at  208 . Then, the arced slot (now inserted) is magnetized in situ at  206 . 
     Therefore, according to one embodiment of the present invention, a component comprises a plurality of magnet elements adjoined to each other, thereby defining an arced segmented magnet section, wherein the arced segmented magnet section is configured to fit in an a curved rotor slot gap of an electric machine. 
     According to another embodiment of the present invention, an electric machine comprises: a rotor core comprising a plurality of laminations; a stator configured with a plurality of stationary windings therein; a plurality of curved rotor slot gaps disposed within the plurality of rotor laminations; and a segmented magnet component disposed in each of the plurality of curved rotor slot gaps. 
     According to another embodiment of the present invention, a method comprises: adjoining a plurality of magnetizable segments next to each other, thereby defining an arced segmented magnet section, wherein each of the plurality of magnetizable segments are a same size and shape; inserting said arced segmented magnet section into a curved rotor slot gap of an electric machine rotor lamination; and magnetizing the arced segmented magnet section. 
     While only certain features of the invention have been illustrated and/or described herein, many modifications and changes will occur to those skilled in the art. Although individual embodiments are discussed, the present invention covers all combination of all of those embodiments. It is understood that the appended claims are intended to cover all such modification and changes as fall within the intent of the invention.

Technology Classification (CPC): 7