# US 7,744,350 B2 · Multiblade fan > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,350 B2 - Document ID: US7744350B2 - Status: Granted - Kind: B2 - Application number: 11/574,774 - Filed: 2004-12-13 - Published: 2007-11-01 - Granted: 2010-06-29 - Earliest claimed: 2004-09-13 - Assignees: Panasonic Corporation - Inventors: Kazuo Ogino; Kazuya Omori - Web page: https://patentgrep.com/patent/US7744350B2 ## CPC - F04D 29/30: Vanes - F04D 29/282: {the leading edge of each vane being substantially parallel to the rotation axis} - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) ## Abstract A multi-blade fan includes a spirally-shaped housing which has a bell-mouth orifice on one side, a sucking inlet and an exhausting outlet, an impeller which is placed in a housing and has a plurality of blades supported by a main plate and a lateral plate at both the axial ends, and a motor for driving the impeller. A cross section, cut along vertically with respect to a rotary shaft of the impeller, of each one of the blades has a given shape which allows a main air stream to flow along a back face of each one of blades. ## Claims ### Claim 1 A multi-blade fan comprising: a spiral shaped housing including a bell-mouth orifice at one side, a sucking inlet and an exhausting outlet; an impeller disposed in the housing and including a plurality of blades supported by a main plate and a lateral plate at both axial ends of each one of the blades, said lateral plate located closer to the bell-mouth orifice than said main plate; and a motor for driving the impeller, wherein a cross section, cut along vertically with respect to a rotary shaft within a first given length, of each one of the blades has a given shape which allows a main air stream to flow along a back face of each one of the blades from a leading edge to a trailing edge of each one of the blades, wherein an axial length of each of the blades comprises a thin-walled section of a second given length and a thick-walled section of a third given length, said thick-walled section extending from said thin-walled section at a transition section so as to reach the trailing edge, the second given length being smaller than the third given length, a thickness of the thin-walled section being smaller than a thickness of the thick-walled section, said transition section oriented substantially perpendicular to the axial length of the blade. ### Claim 2 (depends on 1) The multi-blade fan of claim 1, wherein the first given length is an entire axial length of each one of the blades. ### Claim 3 (depends on 1) The multi-blade fan of claim 1, wherein the given shape includes a change such that the thin-walled section of the back face changes over to the thick-walled section from the leading edge to the trailing edge of each one of the blades. ### Claim 4 (depends on 3) The multi-blade fan of claim 3, wherein the second given length of the thin-walled section is not shorter than 1/20 and not greater than ⅓ of a chord length. ### Claim 5 (depends on 3) The multi-blade fan of claim 3, wherein a the thickness of the thin-walled section is not smaller than 1/10 and not greater than ½ of the thickness of the thick-walled section. ### Claim 6 (depends on 3) The multi-blade fan of claim 3, wherein a junction between the thin-walled section and the thick-walled section shapes like an arc, of which length is not shorter than 1/20 and not longer than 1/10 of a chord length. ### Claim 7 (depends on 3) The multi-blade fan of claim 3, wherein a thickness of the thick-walled section becomes thinner gradually toward the trailing edge. ### Claim 8 (depends on 3) The multi-blade fan of claim 3, wherein the main plate has a circumference smaller than a circumference of the trailing edge of the plurality of blades of the impeller. ### Claim 9 (depends on 3) The multi-blade fan of claim 3, wherein the change comprises a junction between the thin-walled section and the thick-walled section, said junction being substantially orthogonal to the transition section. ### Claim 10 (depends on 1) The multi-blade fan of claim 1, wherein the first given length is not shorter than ⅓ and not greater than ⅔ of the axial length of each one of the blades extending from the main plate. ### Claim 11 (depends on 1) The multi-blade fan of claim 1, wherein the first given length is not shorter than ⅓ and not greater than ⅔ of the axial length of each one of the blades extending from the lateral plate. ### Claim 12 (depends on 1) The multi-blade fan of claim 1, wherein the orifice is formed of a first orifice nearer to the impeller and a second orifice, and the two orifices are disposed with a given interval in between for cutting off sound. ### Claim 13 (depends on 12) The multi-blade fan of claim 12, wherein the first orifice has an inner diameter not shorter than 8/10 and not greater than 1/1 of an inner diameter of the impeller. ### Claim 14 (depends on 12) The multi-blade fan of claim 12, wherein the given interval is not shorter than 1/10 and not longer than ½ of an inner diameter of the first orifice. ### Claim 15 (depends on 12) The multi-blade fan of claim 12, wherein the second orifice has a contour identical to a contour of the first orifice. ### Claim 16 (depends on 12) The multi-blade fan of claim 12, wherein the second orifice has an inner diameter not smaller than ⅔ and not greater than 1/1 of an inner diameter of the first orifice.