# US 12,768,365 B2 · Centrifugal fan with back blades > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,768,365 B2 - Document ID: US12768365B2 - Status: Granted - Kind: B2 - Application number: 18/735,395 - Filed: 2024-06-06 - Published: 2024-10-03 - Granted: 2026-10-20 - Earliest claimed: 2022-01-06 - Assignees: ABB Schweiz AG - Applicants: ABB Schweiz AG - Inventors: Xiaoliang Zhou; Yang Xu; Weimin Li - Web page: https://patentgrep.com/patent/US12768365B2 ## CPC - F04D 29/281: {for fans or blowers} - F04D 1/00: Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps (adapted for pumping specific fluids F04D7/00; priming or boosting F04D9/00) - H02K 9/06: with fans or impellers driven by the machine shaft - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract An electrical machine that includes a centrifugal fan. The centrifugal fan is for cooling an electrical machine and configured to rotate around a rotating axis. The centrifugal fan includes a first plate with an air inlet configured to face a rotor of the electrical machine to receive air; a second plate spaced apart from the first plate in a direction parallel to the rotating axis (R); a plurality of first blades arranged between the first plate and the second plate; and a plurality of second blades arranged on a side of the second plate away from the first plate and configured to reduce an air pressure in vicinity of the second plate. ## Claims ### Claim 1 A centrifugal fan for cooling an electrical machine, the centrifugal fan being configured to rotate around a rotating axis, the centrifugal fan comprising: a first plate comprising an air inlet configured to face a rotor of the electrical machine to receive air; a second plate spaced apart from the first plate in a direction parallel to the rotating axis; a plurality of first blades arranged between the first plate and the second plate; and a plurality of second blades arranged on a side of the second plate away from the first plate and configured to reduce an air pressure in vicinity of the second plate; wherein each of the plurality of first blades has a first arc shape and each of the plurality of the second blades has a second arc shape, and wherein a curvature of the first arc shape is the same as a curvature of the second arc shape. ### Claim 2 (depends on 1) The centrifugal fan of claim 1, wherein the plurality of second blades is dimensioned to reduce a resultant pressure applied to the centrifugal fan in the direction parallel to the rotating axis. ### Claim 3 (depends on 1) The centrifugal fan of claim 1, wherein a dimension of the plurality of second blades is determined based on an outer diameter of the centrifugal fan, a width of the centrifugal fan in the direction parallel to the rotating axis and a distance between the centrifugal fan and an end cover of the electrical machine close to the centrifugal fan. ### Claim 4 (depends on 1) The centrifugal fan of claim 1, wherein each of the plurality of first blades is integrally formed with a respective one of the plurality of second blades, and the second plate comprises a plurality of mounting holes each arranged to support the respective first blade and the respective second blade. ### Claim 5 (depends on 4) The centrifugal fan of claim 4, wherein a cross section of the second blades in a direction perpendicular to the rotating axis is the same as that of the respective mounting hole. ### Claim 6 (depends on 1) The centrifugal fan of claim 1, wherein each of the plurality of second blades extends in a radial direction with respect to the rotating axis. ### Claim 7 (depends on 1) The centrifugal fan of claim 1, wherein the plurality of the second blades is distributed symmetrically on the second plate with respect to the rotating axis. ### Claim 8 (depends on 1) The centrifugal fan of claim 1, wherein the number of the second blades is the same as the number of the first blades. ### Claim 9 (depends on 1) An electrical machine comprising: a housing including two end covers at two axial ends of the housing; a rotor shaft rotatably arranged in two sleeve bearings at the two end covers; and the centrifugal fan according to claim 1, wherein the centrifugal fan is arranged around the rotor shaft. ### Claim 10 (depends on 9) The electrical machine of claim 9, wherein the plurality of second blades is dimensioned to reduce a resultant pressure applied to the centrifugal fan in the direction parallel to the rotating axis. ### Claim 11 (depends on 9) The electrical machine of claim 9, wherein a dimension of the plurality of second blades is determined based on an outer diameter of the centrifugal fan, a width of the centrifugal fan in the direction parallel to the rotating axis and a distance between the centrifugal fan and an end cover of the electrical machine close to the centrifugal fan. ### Claim 12 (depends on 9) The electrical machine of claim 9, wherein each of the plurality of first blades has a first arc shape and each of the plurality of the second blades has a second arc shape, and wherein a curvature of the first arc shape is the same as a curvature of the second arc shape. ### Claim 13 (depends on 9) The electrical machine of claim 9, wherein each of the plurality of first blades is integrally formed with a respective one of the plurality of second blades, and the second plate comprises a plurality of mounting holes each arranged to support the respective first blade and the respective second blade. ### Claim 14 (depends on 13) The electrical machine of claim 13, wherein a cross section of the second blades in a direction perpendicular to the rotating axis is the same as that of the respective mounting hole. ### Claim 15 (depends on 9) The electrical machine of claim 9, wherein each of the plurality of second blades extends in a radial direction with respect to the rotating axis. ### Claim 16 (depends on 9) The electrical machine of claim 9, wherein the plurality of the second blades is distributed symmetrically on the second plate with respect to the rotating axis. ### Claim 17 (depends on 9) The electrical machine of claim 9, wherein the number of the second blades is the same as the number of the first blades.