# US 10,480,527 B2 · Axial fan with unbalanced blade spacing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,527 B2 - Document ID: US10480527B2 - Status: Granted - Kind: B2 - Application number: 15/588,205 - Filed: 2017-05-05 - Published: 2018-11-08 - Granted: 2019-11-19 - Earliest claimed: 2017-05-05 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Robert J. Van Houten; Yoonshik Shin - Web page: https://patentgrep.com/patent/US10480527B2 ## CPC - F04D 29/388: {characterised by construction} - F01P 5/02: Pumping cooling-air; Arrangements of cooling-air pumps, e.g. fans or blowers - F04D 19/002: {Axial flow fans} - F04D 29/325: {for axial flow fans (blade mountings F04D29/34, blades F04D29/38)} - F04D 29/327: {with non identical blades} - F04D 29/328: {with unequal distribution of blades around the hub} - F04D 29/384: {characterised by form} - F04D 29/662: {Balancing of rotors (compensating imbalance G01M1/36)} - F04D 29/666: {by means of rotor construction or layout, e.g. unequal distribution of blades or vanes} - F04D 29/263: {mounting fan or blower rotors on shafts} - F04D 29/38: Blades {(for axial flow compressors F04D29/324)} - F05B 2240/301: Cross-section characteristics - F05B 2260/20: Heat transfer, e.g. cooling - F05D 2260/961: by mistuning rotor blades or stator vanes with irregular interblade spacing, airfoil shape - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F01P: COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES (arrangements in connection with cooling of propulsion units in vehicles B60K11/00; heat-transfer, heat-exchange or heat-storage materials C09K5/00; {cooling of gas-turbine engines F02C7/12}; heat exchange in general, radiators F28) - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract An axial fan comprising a hub and a plurality of blades extending from a periphery of the hub. Each of the blades has a thickness which varies from a leading edge to a trailing edge and from a root to a tip. The blades are unevenly spaced around the periphery of the hub in a pattern which is not balanced. The fan is balanced by variance in blade thickness among the plurality of blades. ## Claims ### Claim 1 An axial fan comprising: a hub; and a plurality of blades extending from a periphery of the hub, wherein each of the plurality of blades has a thickness which varies from a leading edge to a trailing edge and from a root to a tip, wherein the plurality of blades are unevenly spaced around the periphery of the hub in a pattern which is not balanced, and wherein the fan is balanced by variance in blade thickness among the plurality of blades, and the blade thickness of a first blade is scaled by individual blade thickness factors to define the thickness of each of the other blades, said blade thickness factors varying among the plurality of blades in such a way that the fan is balanced. ### Claim 2 (depends on 1) The axial fan of claim 1, wherein the blade thickness factors of all of the plurality of blades are unique. ### Claim 3 (depends on 1) The axial fan of claim 1, wherein the blade thickness factors of all but two of the plurality of blades are unique. ### Claim 4 (depends on 1) The axial fan of claim 1, wherein a ratio defined as the thickness factor of a thickest one of the plurality of blades divided by the thickness factor of a thinnest one of the plurality of blades is at least 1.05. ### Claim 5 (depends on 1) The axial fan of claim 1, wherein a ratio defined as the thickness factor of a thickest one of the plurality of blades divided by the thickness factor of a thinnest one of the plurality of blades is at least 1.10. ### Claim 6 (depends on 1) The axial fan of claim 1, wherein the plurality of blades consists of exactly three blades. ### Claim 7 (depends on 1) The axial fan of claim 1, wherein the plurality of blades consists of exactly four blades. ### Claim 8 (depends on 1) The axial fan of claim 1, wherein a mean surface of each of the plurality of blades is identical. ### Claim 9 (depends on 1) The axial fan of claim 1, wherein the axial fan is a free-tipped axial fan. ### Claim 10 (depends on 1) The axial fan of claim 1, wherein the axial fan is an automotive engine-cooling fan. ### Claim 11 (depends on 1) The axial fan of claim 1, wherein the spacing of the plurality of blades is symmetric about a line of symmetry. ### Claim 12 (depends on 11) The axial fan of claim 11, wherein two of the plurality of blades whose positions are symmetric relative to the line of symmetry have equal thicknesses. ### Claim 13 (depends on 1) The axial fan of claim 1, wherein a ratio defined as a largest spacing angle between adjacent ones of the plurality of blades divided by a smallest spacing angle between adjacent ones of the plurality of blades is at least 1.15. ### Claim 14 (depends on 1) The axial fan of claim 1, wherein a ratio defined as a largest spacing angle between adjacent ones of the plurality of blades divided by a smallest spacing angle between adjacent ones of the plurality of blades is at least 1.20. ### Claim 15 (depends on 1) The axial fan of claim 1, wherein a ratio defined as a largest spacing angle between adjacent ones of the plurality of blades divided by a smallest spacing angle between adjacent ones of the plurality of blades is less than or equal to 1.80. ### Claim 16 (depends on 1) The axial fan of claim 1, wherein a ratio defined as a largest spacing angle between adjacent ones of the plurality of blades divided by a smallest spacing angle between adjacent ones of the plurality of blades is less than or equal to 1.60. ### Claim 17 An axial fan comprising: a hub; and a plurality of blades extending from a periphery of the hub, wherein each of the plurality of blades has a thickness which varies from a leading edge to a trailing edge and from a root to a tip, wherein the plurality of blades are unevenly spaced around the periphery of the hub in a pattern which is not balanced, wherein the fan is balanced by variance in blade thickness among the plurality of blades, and wherein the spacing of the plurality of blades is symmetric about a line of symmetry, and two of the plurality of blades whose positions are symmetric relative to the line of symmetry have equal thicknesses.