# US 10,767,658 B2 · Axial fan and refrigerator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,767,658 B2 - Document ID: US10767658B2 - Status: Granted - Kind: B2 - Application number: 15/791,452 - Filed: 2017-10-24 - Published: 2018-05-17 - Granted: 2020-09-08 - Earliest claimed: 2016-11-11 - Assignees: Nidec Corporation - Applicants: Nidec Corporation - Inventors: Ryosuke Ishida - Web page: https://patentgrep.com/patent/US10767658B2 ## CPC - F04D 29/522: {especially adapted for elastic fluid pumps} - F04D 19/002: {Axial flow fans} - F04D 25/06: the pump being electrically driven (F04D25/08 takes precedence) - F04D 25/0613: {the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator} - F04D 25/08: the working fluid being air, e.g. for ventilation - F04D 29/325: {for axial flow fans (blade mountings F04D29/34, blades F04D29/38)} - F04D 29/526: {Details of the casing section radially opposing blade tips (ducts F04D29/545)} - F04D 29/545: {Ducts} - F25D 17/062: {in household refrigerators} - F25D 21/14: Collecting or removing condensed and defrost water; Drip trays - F25D 2317/0681: Details thereof - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B) ## Abstract An axial fan according to an exemplary embodiment of the present disclosure includes an impeller, a motor, and a housing. The impeller is configured to rotate about a rotation axis extending in a vertical direction. The motor is configured to rotationally drive the impeller. The housing is disposed radially outside the impeller and the motor. In a region overlapping in the vertical direction with the impeller, an inner wall surface of the housing includes at least one first wall having a narrow gap with a radially outer edge of the impeller and at least one second wall having a wide gap with the radially outer edge of the impeller. ## Claims ### Claim 1 An axial fan comprising: an impeller to rotate about a rotation axis extending in a vertical direction; a motor to rotationally drive the impeller; a housing radially outside the impeller and the motor; an intake port provided at an upper portion of the housing in the vertical direction; and an exhaust port provided at a lower portion of the housing in the vertical direction; wherein in a region overlapping in the vertical direction with the impeller, an inner wall surface of the housing includes at least one first wall including a narrow gap with a radially outer edge of the impeller and at least one second wall including a wide gap with the radially outer edge of the impeller; the housing includes a bottom plate at the lower portion; an outer wall surface of the housing extends upward from the outer edge of the bottom plate and has a square or substantially square shape in a cross-sectional view perpendicular to the vertical direction; the at least one first wall extends from the bottom plate to an upper end of the housing; the housing includes a space provided between the at least one second wall and the impeller; the space is defined by an empty void which extends all the way from the bottom plate to the upper end of the housing; the at least one first wall is provided in the center of one side of the housing; the at least one second wall includes a plurality of second walls located at positions nearer to four corners of the housing than the first wall is; the exhaust port is a circular opening; and an inner wall surface of the at least one first wall is flush with a circumferential edge of the exhaust port such that the inner wall surface of the at least one first wall and the circumferential edge of the exhaust port overlap with each other in an axial view parallel to the vertical direction. ### Claim 2 (depends on 1) The axial fan according to claim 1, wherein the inner surface of the first wall is part of a cylindrical shape centered on the rotation axis. ### Claim 3 (depends on 2) The axial fan according to claim 2, wherein a circumferential length of the first wall differs from a circumferential distance between radially outer ends of adjacent blades of the impeller. ### Claim 4 (depends on 1) The axial fan according to claim 1, further comprising: a motor base portion that supports the motor; and a rib connecting the motor base portion and the housing together, and wherein an upper surface of the rib includes an inclined surface that is inclined downward toward a forward end of the impeller in the rotating direction. ### Claim 5 (depends on 4) The axial fan according to claim 4, further comprising: a ring-shaped rib centered on the rotation axis and connected to the rib, wherein an upper surface of the ring-shaped rib includes an inclined surface that is inclined downward toward radially outside. ### Claim 6 (depends on 1) The axial fan according to claim 1, wherein the number of the first walls and the number of blades of the impeller are prime to each other. ### Claim 7 (depends on 1) The axial fan according to claim 1, wherein the at least one first wall comprises a plurality of first wall, and wherein the plurality of first walls are equal in length along the inner wall surface. ### Claim 8 (depends on 1) The axial fan according to claim 1, wherein both circumferential ends of the first wall are provided on an inner wall surface of one side of the substantially rectangular shape. ### Claim 9 (depends on 1) The axial fan according to claim 1, wherein both circumferential ends of the first wall are disposed on an inner wall surface of different sides of the substantially rectangular shape. ### Claim 10 (depends on 1) The axial fan according to claim 1, wherein the inner surface of the first wall includes a groove that is recessed radially outward and extending to an end of the housing in the vertical direction. ### Claim 11 (depends on 10) The axial fan according to claim 10, wherein one end of the groove is disposed adjacent to the intake port, and wherein the groove decreases in depth toward the end of the housing in the vertical direction. ### Claim 12 (depends on 1) The axial fan according to claim 1, wherein the gap between the second wall and the impeller increases toward one end in the vertical direction. ### Claim 13 (depends on 1) A refrigerator comprising the axial fan according to claim 1. ### Claim 14 (depends on 13) The refrigerator according to claim 13, further comprising: a duct, wherein a channel of the duct extends in a direction from the rotation axis to the second wall.