# US 10,479,651 B2 · Cooling of machine for elevator system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,651 B2 - Document ID: US10479651B2 - Status: Granted - Kind: B2 - Application number: 15/029,706 - Filed: 2013-10-17 - Published: 2016-09-01 - Granted: 2019-11-19 - Earliest claimed: 2013-10-17 - Assignees: Otis Elevator Company - Applicants: Otis Elevator Company - Inventors: Zlatko Strbuncelj - Web page: https://patentgrep.com/patent/US10479651B2 ## CPC - B66B 11/043: {actuated by rotating motor; Details, e.g. ventilation (roping on drum, sheave, winch or pulley B66B11/0065; power supply or control B66B1/28, H02P; motor construction H02K)} - H02K 1/20: with channels or ducts for flow of cooling medium - H02K 5/18: with ribs or fins for improving heat transfer - H02K 7/1016: {Machine of the outer rotor type} - H02K 7/102: with friction brakes - H02K 9/04: having means for generating a flow of cooling medium - B66B: ELEVATORS; ESCALATORS OR MOVING WALKWAYS ({apparatus for raising or lowering persons on theatrical stages or the like A63J5/12} ; funicular railbound systems with rigid ground-supported tracks and cable traction, e.g. cliff railways, B61B9/00; arrangements of ammunition handlers in vessels B63G3/00; hoists, lifts, or conveyors for loading or unloading in general B65G; braking or detent devices controlling normal movements of winding drums or barrels B66D; ship-lifting devices E02C; garages for many vehicles with mechanical means for lifting vehicles E04H6/12; hoists for feeding ammunition or projectiles to launching apparatus or to loading mechanisms F41A9/00) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract An electric machine includes a rotor including a plurality of permanent magnets. The rotor is rotatable about a central axis of the machine. The machine further includes a stator having a stator hub and a plurality of stator windings positioned at the stator hub and located radially inboard of the plurality of permanent magnets. A plurality of fins extend radially inwardly from an inner surface of the stator hub. ## Claims ### Claim 1 An elevator system comprising: an elevator car; a drive member operably connected to the elevator car; a traction sheave in frictional contact with the drive member; a machine operably connected to the traction sheave, the machine including: a rotor including a plurality of permanent magnets, the rotor rotatable about a central axis of the machine; a stator including: a stator hub; a plurality of stator windings disposed at the stator hub and located radially inboard of the plurality of permanent magnets; and a plurality of fins extending radially inwardly from an inner surface of the stator hub, the plurality of fins including: one or more first fins having a first circumferential thickness; and one or more second fins having a second circumferential thickness different from the first circumferential thickness; a central shaft fixed to and supportive of the stator, the rotor configured to rotate relative to the central shaft, the central shaft including: an open end; a plurality of cooling openings in the central shaft configured such that a cooling airflow flows into the central shaft via the open end and out of the shaft via the plurality of cooling openings and across the plurality of fins to cool the stator; and a cap disposed at and defining a closed end opposite the open end, the cap configured to prevent the cooling airflow from bypassing the plurality of cooling openings; and a stator support fixed to the central shaft, the stator support extending radially outwardly from the central shaft to the stator hub to support the stator hub. ### Claim 2 (depends on 1) The elevator system of claim 1, wherein the plurality of fins are formed integral to the stator hub. ### Claim 3 (depends on 1) The elevator system of claim 1, further comprising a blower to urge the cooling airflow across the plurality of fins to cool the plurality of stator windings. ### Claim 4 (depends on 1) The elevator system of claim 1, wherein the plurality of fins extend substantially axially along the inner surface. ### Claim 5 An electric machine comprising: a rotor including a plurality of permanent magnets, the rotor rotatable about a central axis of the machine; a stator including: a stator hub; a plurality of stator windings disposed at the stator hub and located radially inboard of the plurality of permanent magnets; and a plurality of fins extending radially inwardly from an inner surface of the stator hub, the plurality of fins including: one or more first fins having a first circumferential thickness; and one or more second fins having a second circumferential thickness different from the first circumferential thickness; a central shaft fixed to and supportive of the stator, the rotor configured to rotate relative to the central shaft, the central shaft including: an open end; a plurality of cooling openings in the central shaft configured such that a cooling airflow flows into the central shaft via the open end and out of the shaft via the plurality of cooling openings and across the plurality of fins to cool the stator; and a cap disposed at and defining a closed end opposite the open end, the cap configured to prevent the cooling airflow from bypassing the plurality of cooling openings; and a stator support fixed to the central shaft, the stator support extending radially outwardly from the central shaft to the stator hub to support the stator hub. ### Claim 6 (depends on 5) The machine of claim 5, wherein the plurality of fins are formed integral to the stator hub. ### Claim 7 (depends on 6) The machine of claim 6, wherein the plurality of fins are formed integral to the stator hub by casting with the stator hub. ### Claim 8 (depends on 5) The machine of claim 5, further comprising a blower to urge the cooling airflow across the plurality of fins to cool the plurality of stator windings. ### Claim 9 (depends on 5) The machine of claim 5, wherein the plurality of fins extend substantially axially along the inner surface. ### Claim 10 A method of cooling stator windings of an electric machine comprising: urging a cooling airflow into the machine via an open end of a central shaft toward a stator assembly of the machine, the stator assembly including: a stator hub; a plurality of stator windings disposed at the stator hub and located radially inboard of a rotor of the electric machine; and a plurality of fins extending radially inwardly from an inner surface of the stator hub, the plurality of fins including: one or more first fins having a first circumferential thickness; and one or more second fins having a second circumferential thickness different from the first circumferential thickness; and a cap disposed at and defining a closed end opposite the open end; flowing the cooling airflow out of the central shaft via a plurality of cooling openings in the central shaft, the cap configured to prevent the cooling airflow from bypassing the plurality of cooling openings; flowing the cooling airflow through a stator support, the stator support fixed to the central shaft and extending radially outwardly from the central shaft to the stator hub; flowing the cooling airflow across the plurality of fins, thus transferring thermal energy between the cooling airflow and the plurality of stator windings; and cooling the plurality of stator windings via the thermal energy transfer.