# US 11,999,045 B2 · Work tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,999,045 B2 - Document ID: US11999045B2 - Status: Granted - Kind: B2 - Application number: 17/601,961 - Filed: 2020-04-13 - Published: 2022-06-16 - Granted: 2024-06-04 - Earliest claimed: 2019-04-22 - Assignees: Makita Corporation - Applicants: Makita Corporation - Inventors: Yonosuke Aoki - Web page: https://patentgrep.com/patent/US11999045B2 ## CPC - B25F 5/008: {Cooling means} - B25F 5/02: Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} - B26D 1/06: wherein the cutting member reciprocates (cup or like cutting members B26D1/44) - 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)} - B26D: CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING (for growing crops or plants A01D, A01G; for fodder or straw A01F; for bulk butter A01J; for dough A21C; slaughtering A22B; for tobacco, cigars or cigarettes A24; marking-out, perforating or making buttonholes A41H25/00; manufacturing footwear A43D; brushmaking A46D; surgery A61B; disintegrating, mincing or shredding in general B02C; cutting wire, making pins or nails B21F, B21G; of the kind used formetal B23; cutting by abrasive fluid jets B24C5/02; hand-held cutting tools B26B; perforating, cutting-out, stamping-out or punching, or severing by means other than cutting B26F; for wood B27; for stone B28D; working of plastics or substances in a plastic state B29; making boxes, cartons, envelopes or bags, of paper or similarly worked materials, e.g. metal foil, B31B; article or web delivery apparatus incorporating cutting or line-perforating devices B65H35/00; for leather or upholstery B68, C14B; for glass C03B; making matches C06F; for peat C10F; for sugar C13B45/00; for textile materials D06H; civil engineering, building, mining, see Section E; for light guides G02B6/25; cutting processed photographic material G03D15/04) ## Abstract A work tool includes a housing, a spindle, a motor a transmitting mechanism, and a heat dissipation part. The transmitting mechanism is configured to transmit rotation of a first shaft of the motor to the spindle to cause the spindle to rotary oscillate. The transmitting mechanism includes a metal second shaft coupled to the first shaft and having an eccentric part, a drive bearing including an inner ring fixed around the eccentric part, an outer ring, a plastic retainer arranged between the inner ring and the outer ring, and rolling elements rollably retained by the retainer, and an oscillating member having a first end portion fixed to the spindle and a second end portion abutting on an outer periphery of the outer ring. The heat dissipation part is made of metal, arranged in contact with the second shaft and configured to rotate integrally with the second shaft. ## Claims ### Claim 1 A work tool configured to drive a tool accessory in an oscillating manner to perform a processing operation on a workpiece, the work tool comprising: a housing; a spindle supported by the housing to be rotatable around a first rotational axis; a motor housed in the housing and including a stator, a rotor, and a first shaft, the first shaft extending from the rotor and being configured to rotate integrally with the rotor around a second rotational axis; a transmitting mechanism configured to transmit rotation of the first shaft to the spindle to cause the spindle to rotary oscillate around the first rotational axis; and a heat dissipation part, wherein: the transmitting mechanism comprises: a second shaft made of metal and coaxially coupled to the first shaft and having an eccentric part that is eccentric to the second rotational axis; a drive bearing including an inner ring fixed around the eccentric part, an outer ring, a retainer made of plastic and between the inner ring and the outer ring, and a plurality of rolling elements rollably retained by the retainer; and an oscillating member having a first end portion fixed to the spindle and a second end portion abutting on an outer periphery of the outer ring of the drive bearing; the heat dissipation part is made of metal, in contact with the second shaft and configured to rotate integrally with the second shaft; and the housing has a first path that directs an airflow for cooling the motor to the motor and a second path that (i) is different from the first path and (ii) directs an airflow to the heat dissipation part for cooling the heat dissipation part. ### Claim 2 (depends on 1) The work tool as defined in claim 1, wherein the heat dissipation part protrudes radially outward from the second shaft and has an intersecting surface that intersects a rotation direction of the heat dissipation part. ### Claim 3 (depends on 1) The work tool as defined in claim 1, wherein the heat dissipation part is a fan that is configured to be rotated by power of the motor to generate an airflow that flows into the housing through an inlet of the housing. ### Claim 4 (depends on 1) The work tool as defined in claim 1, further comprising: a fan configured to be rotated integrally with the second shaft by power of the motor to generate an airflow that flows into the housing through an inlet of the housing, wherein the heat dissipation part is a discrete member from the fan. ### Claim 5 (depends on 4) The work tool as defined in claim 4, wherein the heat dissipation part is between the fan and the drive bearing in an axial direction of the second rotational axis. ### Claim 6 (depends on 1) The work tool as defined in claim 1, wherein the fan is a single fan having a plurality of first blades configured to generate the airflow that flows along the first path, and a plurality of second blades configured to generate the airflow that flows along the second path. ### Claim 7 (depends on 6) The work tool as defined in claim 6, wherein the number of the plurality of second blades is larger than the number of the plurality of first blades. ### Claim 8 (depends on 1) The work tool as defined in claim 1, wherein: the motor is a brushless motor, and the second path passes a radially outward region of a motor body that includes the stator and the rotor. ### Claim 9 (depends on 1) The work tool as defined in claim 1, wherein the first rotational axis and the second rotational axis are parallel to each other. ### Claim 10 (depends on 3) The work tool as defined in claim 3, wherein the fan is a single fan having a plurality of first blades configured to generate the airflow that flows along the first path, and a plurality of second blades configured to generate the airflow that flows along the second path. ### Claim 11 (depends on 10) The work tool as defined in claim 10, wherein the fan is a centrifugal fan configured to draw air from two directions. ### Claim 12 (depends on 11) The work tool as defined in claim 11, wherein the number of the plurality of second blades is larger than the number of the plurality of first blades. ### Claim 13 (depends on 12) The work tool as defined in claim 12, wherein: the motor is a brushless motor, and the second path passes a radially outward region of a motor body that includes the stator and the rotor.