# US 2021/0242731 A1 · Electric motor for a power tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242731 A1 - Document ID: US20210242731A1 - Status: Published application - Kind: A1 - Application number: 17/165,023 - Filed: 2021-02-02 - Published: 2021-08-05 - Earliest claimed: 2020-02-05 - Assignees: Milwaukee Electric Tool Corporation - Applicants: Milwaukee Electric Tool Corporation - Inventors: Andrew T. Beyerl; Derek J. Schwab; Samantha L. Billetdeaux; Kyle Greunke; Hans T. Banholzer; Carmen J. Castanos - Web page: https://patentgrep.com/patent/US20210242731A1 ## CPC - B25F 5/02: Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} - H02K 1/185: {to outer stators} - B23D 51/16: of drives or feed mechanisms for straight tools, e.g. saw blades, or bows - B25F 5/008: {Cooling means} - H02K 1/146: {consisting of a generally annular yoke with salient poles} - H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] - H02K 3/522: {for generally annular cores with salient poles} - H02K 5/161: {radially supporting the rotary shaft at both ends of the rotor (H02K5/165, H02K5/167, H02K5/173 take precedence)} - H02K 5/1732: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence)} - H02K 7/083: {radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence)} - H02K 7/145: {Hand-held machine tool} - H02K 9/06: with fans or impellers driven by the machine shaft - H02K 9/227: {Heat sinks} - H02K 11/33: Drive circuits, e.g. power electronics (H02K11/38 takes precedence) - H02K 21/16: having annular armature cores with salient poles (with homopolar co-operation H02K21/20) - H02K 2211/03: Machines characterised by circuit boards, e.g. pcb - B25F: COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR {(machines or arrangements of machines for performing specified combinations of different metal-working operations not covered by a single other subclass B23P23/00 and subgroups)} - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - B23D: PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR (making toothed gears or the like B23F; cutting metal by applying heat locally B23K; arrangements for copying or controlling B23Q) ## Abstract A power tool includes a housing having a rear wall, a motor assembly coupled to the rear wall, and a plurality of mounting legs projecting from the rear wall toward the motor assembly. The motor assembly defines a motor axis, and includes a stator assembly defining a plurality of axially extending mounting apertures. Each mounting leg defines a threaded boss corresponding to a respective mounting aperture of the stator assembly, and each threaded boss is configured to receive a threaded fastener. The mounting legs are angularly spaced at unequal intervals about the motor axis. ## Claims ### Claim 1 A power tool comprising: a housing defining a longitudinal axis and including a rear wall; a motor assembly coupled to the rear wall, the motor assembly including a stator assembly defining a plurality of axially extending mounting apertures; a plurality of mounting legs projecting from the rear wall toward the motor assembly, each mounting leg defining a threaded boss corresponding to a respective mounting aperture of the stator assembly, each threaded boss configured to receive a threaded fastener; wherein the mounting legs are angularly spaced at unequal intervals about the longitudinal axis. ### Claim 2 (depends on 1) The power tool of claim 1, wherein the rear wall extends perpendicular to the longitudinal axis. ### Claim 3 (depends on 2) The power tool of claim 2, wherein the mounting legs include a first mounting leg, a second mounting leg, and a third mounting leg. ### Claim 4 (depends on 3) The power tool of claim 3, wherein a first mounting leg angle A1 is defined between the first mounting leg and the second mounting leg about the longitudinal axis, a second mounting leg angle A2 is defined between the second mounting leg and the third mounting leg about the longitudinal axis, and a third mounting leg angle A3 is defined between the third mounting leg and the first mounting leg about the longitudinal axis, and wherein A1=A2≠A3. ### Claim 5 (depends on 1) The power tool of claim 1, wherein the stator assembly includes a stator body having a plurality of axially extending mounting ribs projecting radially outward from the stator body, and wherein the mounting apertures are defined in the mounting ribs. ### Claim 6 (depends on 5) The power tool of claim 5, wherein each mounting aperture aligns with a corresponding mounting leg. ### Claim 7 (depends on 5) The power tool of claim 5, wherein each mounting leg includes a pair of projections and an alignment groove defined between the projections, and wherein a portion of each mounting rib is received into a corresponding alignment groove. ### Claim 8 (depends on 5) The power tool of claim 5, further comprising: a circuit board proximate an end of the stator assembly, the circuit board including a heat-generating component; and a heat sink coupled to the stator assembly and in thermal contact with the circuit board, the heat sink including a plurality of mounting tabs extending outward from a periphery of the heat sink and defining fastener apertures; wherein each fastener aperture aligns with a corresponding mounting aperture. ### Claim 9 A power tool comprising: a housing; a motor assembly supported in the housing, the motor assembly including a stator assembly, a circuit board proximate an end of the stator assembly, the circuit board including a heat-generating component, and a heat sink coupled to the stator assembly and in thermal contact with the circuit board, the heat sink having an end wall defining a bearing pocket, and a plurality of axially extending cooling flanges extending from a periphery of the end wall. ### Claim 10 (depends on 9) The power tool of claim 9, wherein each cooling flange defines an airflow aperture. ### Claim 11 (depends on 9) The power tool of claim 9, wherein the circuit board is fastened to the heat sink via first fasteners. ### Claim 12 (depends on 9) The power tool of claim 9, wherein the stator assembly defines a plurality of axially extending mounting apertures, and wherein the housing defines a rear wall and a plurality of mounting legs projecting from the rear wall toward the motor assembly, each mounting leg defining a threaded boss corresponding to a respective mounting aperture of the stator assembly, each threaded boss configured to receive a threaded fastener. ### Claim 13 (depends on 12) The power tool of claim 12, wherein the housing defines a longitudinal axis, and wherein the mounting legs are angularly spaced about the longitudinal axis at unequal intervals. ### Claim 14 (depends on 12) The power tool of claim 12, wherein the stator assembly includes a stator body having a plurality of axially extending mounting ribs projecting radially outward from the stator body, and wherein the mounting apertures are defined in the mounting ribs. ### Claim 15 (depends on 14) The power tool of claim 14, wherein each mounting leg includes a pair of projections and an alignment groove defined between the projections, and wherein a portion of each mounting rib is received into a corresponding alignment groove. ### Claim 16 (depends on 12) The power tool of claim 12, wherein the heat sink includes a plurality of mounting tabs extending outward from a periphery of the heat sink and defining fastener apertures, and wherein each fastener aperture aligns with a corresponding mounting aperture. ### Claim 17 An electric motor assembly comprising: a circuit board; a stator assembly having a first end coupled to the circuit board and a second end opposite the first end, the stator assembly including an annular stator body having a plurality of inwardly projecting teeth, windings wrapped about the stator body to form a plurality of coils, and a terminal coupled to an outer periphery of the stator body and extending longitudinally between the first end and the second end, the terminal being coupled to the circuit board at the first end and being coupled to the windings at the second end to electrically connect the windings to the circuit board; wherein the terminal is molded to an attachment member, and the attachment member is molded to the outer periphery of the stator body. ### Claim 18 (depends on 17) The electric motor assembly of claim 17, wherein the terminal includes a central plate portion, a connecting portion extending from the central plate portion and electrically coupled to the circuit board at the first end, and a hook portion extending from the central plate portion and configured to engage the windings at the second end. ### Claim 19 (depends on 17) The electric motor assembly of claim 17, further comprising a heat sink coupled to the stator assembly and in thermal contact with the circuit board, the heat sink having an end wall defining a bearing pocket, and a plurality of axially extending cooling flanges extending from a periphery of the end wall. ### Claim 20 (depends on 19) The electric motor assembly of claim 19, wherein each cooling flange defines an airflow aperture.