HEAT SINK FOR ARMATURES

An electric motor comprising a motor body formed by a set of laminations defining a longitudinal axis, the laminations defining a plurality of slots and a plurality of poles extending generally parallel to the longitudinal axis. Each of the slots includes a winding positioned therein and a heat sink member positioned within a portion of the slots. The heat sink member is a single continuous member that passes through the portion of the slots. Alternatively, the electric motor can include a plurality of heat sink members and a common heat sink member, with a portion of the slots including at least one heat sink member. Each of the heat sink members is coupled to the common heat sink member.

DETAILED DESCRIPTION

With reference toFIG. 1, an electric motor assembly10includes a stator assembly14and a rotor assembly18. The stator assembly14includes a stator, or first motor body22, and the rotor assembly18includes a rotor, or second motor body26, having a shaft30defining a longitudinal, rotational axis34. The stator22is formed of a plurality of stator laminations38and the rotor26is formed of a plurality of rotor laminations42(e.g., magnetic steel laminations). Alternatively, the stator22or the rotor26can be formed of drawn steel, rolled steel, soft magnetic composite material or any other such material. The stator laminations38define two stator poles46and two stator slots50defined between the stator poles46when coupled together (FIG. 8). The rotor laminations42similarly define twelve rotor poles54and twelve rotor slots58defined between the rotor poles54when coupled together (FIG. 3). The stator poles46, the stator slots50, the rotor poles54, and the rotor slots58extend generally parallel to the longitudinal, rotational axis34. The electric motor assembly10will be described herein as a motor, but is not limited to motoring applications since such an assembly could be used in a generator as well.

The stator assembly14further includes a stator winding62(e.g., a field winding) positioned within the stator slots50and wound around the stator poles46defined by the stator laminations38. The stator winding62includes an exposed portion66(e.g., end windings) and a contained portion70contained within the stator laminations38, or slots50. The rotor assembly18further includes a rotor winding74(e.g., an armature winding) positioned within the rotor slots58and wound around the rotor poles54defined by the rotor laminations42. The rotor winding74includes an exposed portion78(e.g., end windings) and a contained portion82contained within the rotor laminations42. The rotor windings74are electrically connected to a commutator assembly86supported on the shaft30. The commutator assembly86delivers electrical current to the rotor windings74via a brush assembly (not shown). The electric motor assembly illustrated inFIG. 1includes a first heat sink configuration100on the rotor assembly18and a fourth heat sink configuration400on the stator assembly14. Various heat sink configurations are applicable to the electric motor assembly ofFIG. 1and individual embodiments of the invention are described in detail below with common feature referenced identically.

FIG. 2illustrates a heat sink configuration100according to one embodiment of the invention. The heat sink configuration100includes a continuous heat sink member104placed within the rotor slots58, proximal to the rotor windings74. The continuous heat sink member104is wound around the rotor poles54through each of the rotor slots58. The continuous heat sink member104includes exposed portions108(e.g., curved end portions) and contained portions112positioned within the rotor slots58. The exposed portions108curve from one rotor slot58to an adjacent rotor slot. In the illustrated embodiment, twelve exposed and contained portions are shown, although in further embodiments, fewer or more portions may be used and may be dependent upon the number of rotor poles and rotor slots used with the rotor assembly.

With reference toFIG. 3, the contained heat sink portions112are in thermal contact with the contained rotor winding portions82. An insulator90is disposed in each rotor slot58to encapsulate the contained heat sink portions112and the contained rotor winding portions82and to fill the rotor slot58. The contained portions112of the continuous heat sink member104absorb heat from the contained portions82of the rotor winding74. The contained heat sink portions112then effectively conduct the heat to the exposed heat sink portions108, outside of the rotor laminations42. The continuous heat sink member104has a greater thermal conductivity, when compared to the thermal conductivity of the rotor winding74(i.e., heat energy can more easily travel in the heat sink member104than in the rotor winding74). The contained portions82of the heat sink104are able to reduce the temperature of the contained portions82of the winding74by more efficiently conducting the thermal energy to outside of the laminations42. The exposed portions108of the heat sink104and the exposed portions78of the rotor winding74are cooled by being exposed to ambient air, or by forced air cooling.

FIGS. 4,4A and5illustrate a heat sink configuration200according to another embodiment of the invention. The heat sink configuration200includes heat sink member204positioned in each of the rotor slots58. Each of the heat sink members204includes a first end208, a second end212, and a middle portion216. The heat sink members204are positioned within the rotor slots58such that the first end208and the second end212are located at a first end220of the rotor26, and the middle portion216is located at an opposite, second end224of the rotor26. A common heat sink member228, or disk, is mounted on the shaft30for co-rotation at the first end220of the rotor26, and includes support slots232in which to receive corresponding heat sink member204. In the illustrated embodiment, the first end208and the second end212of the heat sink member204are received by the support slots232. The first end208is positioned within the slot232with the heat sink member204, passing through the rotor slot58at the first end220, and exiting the rotor slot58at the second end224. After exiting the rotor slot58at the second end224, the heat sink member204folds at the middle portion216and passes back through the same rotor slot58with the second end212of the heat sink member204terminating at the slot232of the common heat sink member228. The first end208and the second end212of the heat sink members204are secured (i.e, welded or soldered) into place on the common heat sink member228. In other constructions, the heat sink members204and the common heat sink member228are a single, integrated component.

Referring toFIG. 5, each rotor slot58includes a contained portion236having a first cross sectional area240and a second cross sectional area244for each heat sink member204(i.e., each slot contains two passes of the same heat sink member). An exposed heat sink portion248includes the middle portion216, the first end208, and the second end212of each of the heat sink members204, in addition to the common heat sink member228. The contained portion236is placed in thermal contact with the rotor winding74. The heat sink member204therefore conducts heat generated by the contained winding portion82to the exposed portion248of the heat sink configuration200. The contained rotor winding portion82is in thermal contact with both the first cross-sectional area240and the second cross-sectional area244. The common heat sink member228provides a large thermal mass with which the dissipative energy from the winding74can be absorbed into. Similar to the configuration100discussed above, the dissipative heat from the contained rotor winding portions82is efficiently brought to outside of the rotor laminations42by the heat sink members204where the heat can be dispersed into the surrounding environment.

FIG. 6illustrates a heat sink configuration300according to another embodiment of the invention. The heat sink configuration300includes heat sink members304coupled to a common heat sink member308. In the illustrated embodiment, the common heat sink member308is a fan having fan blades312coupled to the shaft30for co-rotation. Each of the heat sink members304includes a first end316coupled to the fan308, a second end320coupled to the fan308, and a middle portion324extending therebetween. The heat sink members304are positioned within the rotor slots58such that the first end316and the second end320are in thermal contact with the fan308, and the middle portion324is curved, extending beyond the rotor laminations42at an opposing end328of the rotor26. Each rotor slot58includes one pass of the heat sink member304positioned proximate to the rotor winding74, and the heat sink member304is positioned within a pair of adjacent rotor slots58. The first end316and the second end320of the heat sink members304are in thermal contact with the fan308so that heat dissipated in the contained rotor winding portion82is conducted from the heat sink member304to the fan308. The fan308creates an air flow when co-rotating with the shaft30, and the generated air flow improves the cooling of the heat sink members304, and also cools the fan308itself.

FIGS. 7 and 8illustrate a heat sink configuration400according to another embodiment of the invention. The heat sink configuration400includes a stator assembly14with heat sink members404positioned within the stator slots50and in thermal contact with the stator windings62. Each of the heat sink members404includes an exposed portion408that follows the general curvature of the stator end windings66. The heat sink members404further include a contained portion412within the stator slots50. The heat sink members404are a single, continuous piece formed into the stator slot50. In the illustrated embodiment, there is one continuous heat sink member404corresponding to each of the stator poles46. The contained heat sink portion412proximate to the contained stator winding portion70draws dissipative heat from the contained stator winding portion70and conducts the heat to the exposed heat sink portion408. Similar to the previous heat sink configurations, the heat sink members404are more effective conductors of thermal energy, so the heat from the stator winding62is more readily brought out of the stator laminations38where the heat can be dissipated to the surroundings. In other embodiments, the heat sink members404are formed in a first piece extending approximately half of a stator length defined by the longitudinal axis34from a first end416of the stator22, and a second piece extending approximately half of the stator length inserted from a second end420of the stator22.

The heat sink members of all the embodiments described above can be made of a copper or aluminum based material and can include a wire insulating film. Various features and advantages of the invention are set forth in the following claims.