EP0385298A2
Expired / Lapsed
EP
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Electric blower having improved return passage for discharged air flow
Assignee: Hitachi Ltd
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Filing: 1990-02-23
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Granted: —
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Expires: 2010-02-23
Abstract
Abstract An electric blower has an electric motor (2) driving a rotating centrifugal impeller (32), an end bracket (21) for separating the electric motor (2) from the centrifugal impeller (32), and a diffuser (31). A flat plate (31b) extends between the impeller (32) and the end bracket (21) for supporting diffuser vanes (31a) and has a plurality of guide vanes (31c) formed opposite to the diffuser vanes (31a). A passage is defined by the end bracket (21), the flat plate (31b) and the guide vanes (31c) so as to return the air flow discharged from the centrifugal impeller (32). The end bracket (21) is formed in a substantially convex shape so as to come away from the flat plate portion (31b) of the diffuser (31) according as the end bracket (21) extends from its central portion toward its periphery, thereby securing an opening area of the discharge air flow return passage in which a sound absorbing material (11; 111; 311) is arranged to absorb sounds from the discharge air flow.
Inventors
- 👤 Hisanori Sakuragawaryo Toyoshima
- 👤 Fumio Jyoraku
- 👤 Yoshitaro 3-7 Ishii
- 👤 Yukiji 1071-22 Iwase
- 👤 Shigenori 2625-3-2-504 Sato
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 07:31
CPC Classifications
F; F04; F04D; F04D17/00; A; A47; A47L; A47L5/00; A47L5/12; A47L5/22; A47L9/00; A47L9/22; F04D25/00; F04D25/02; F04D25/08; F04D25/082; F04D29/00; F04D29/40; F04D29/42; F04D29/44; F04D29/441; F04D29/444; F04D29/58; F04D29/5806; F04D29/66; F04D29/661; F04D29/663; F04D29/664; F05; F05D; F05D2250/00; F05D2250/50; F05D2250/52
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
198 words
An electric blower having: an electric motor; a centrifugal impeller connected to a rotary shaft of the electric motor for rotation therewith; end bracket means for separating the electric motor from the centrifugal impeller; a diffuser including a flat plate portion extending between the centrifugal impeller and the end bracket means and a plurality of diffuser vanes formed on the flat plate portion close to an outer periphery of the centrifugal impeller, the flat plate portion having a plurality of guide vanes formed on a opposite surface of the flat plate portion from the diffuser vanes; a discharge air flow return passage defined by the end bracket means, the flat plate and the guide vanes for returning a discharge air flow from the centrifugal impeller inwardly of the blower; and an sound absorbing material arranged in the return passage, characterized in that said end bracket means (21) is formed in a substantially convex shape so as to come away from said flat plate portion (31b) of said diffuser (31) according as said end bracket means extends from a central portion thereof toward an outer periphery thereof, thereby securing an opening area of said discharge air flow return passage.
Claim 2
Dependent Claim
198 words
An electric blower having: an electric motor; a centrifugal impeller connected to a rotary shaft of the electric motor for rotation therewith; end bracket means for separating the electric motor from the centrifugal impeller; a diffuser including a flat plate portion extending between the centrifugal impeller and the end bracket means and a plurality of diffuser vanes formed on the flat plate portion close to an outer periphery of the centrifugal impeller, the flat plate portion having a plurality of guide vanes formed on a opposite surface of the flat plate portion from the diffuser vanes; a discharge air flow return passage defined by the end bracket means, the flat plate and the guide vanes for returning a discharge air flow from the centrifugal impeller inwardly of the blower; and an sound absorbing material arranged in the return passage, characterized in that said end bracket means (21) is formed in a substantially convex shape so as to come away from said flat plate portion (31b) of said diffuser (31) according as said end bracket means extends from a central portion thereof toward an outer periphery thereof, thereby securing an opening area of said discharge air flow return passage.
Claim 3
Dependent Claim
94 words
The electric blower according to claim 1, characterized in that said electric motor (2) includes a case and a rotor (22) housed in said case, and said end bracked means (21) includes a central portion (21a) for holding a bearing of said rolor (22), an annular flat portion (21b) of an outer periphery, support portion (21c) for interconnecting said central portion (21a) and said annular flat portion (21b) with each other, and at least one through-hole (21d) formed for allowing the discharge air flow to flow through said case of said electric motor (2).
Claim 4
Dependent Claim
29 words
The electric blower according to claim 1, characterized in that said sound absorbing material (11) is arranged on said annular flat portion (21b) of said end bracket means (21).
Claim 5
Dependent Claim
37 words
The electric blower according to claim 1, characterized in that said sound abosrbing material (111; 311) is attached onto a surfaces of said flat plate portion (31b) of said diffuser (31) on a guide vanes (31c) side.
Claim 6
Dependent Claim
49 words
The electric blower according to claim 4, characterized in that said end bracket means (21) has at least one through-hole (21d) for allowing the discharge air flow to pass to cool said electric motor (2), and said sound absorbing material (311) includes a surface inclined toward said through-hole (21d).
Claim 7
Dependent Claim
44 words
The electric blower according to any one of claims 1 to 5, characterized in that said sound absorbing material (11) is received in at least one frame (12; 212) and is attached through said frame (12; 212) in side discharge air flow return passage.
Claim 8
Dependent Claim
22 words
The electric blower according to claim 6, characterized in that said frame (12; 212) is formed in a shape of an annulus.
Claim 9
Dependent Claim
41 words
The electric blower according to claim 6 or 7, characterized in that said frame (12) is formed on at least a side thereof facing said return passage with an opening (12a) which extends along a longitudinal direction of said frame (12).
Claim 10
Dependent Claim
38 words
The electric blower according to claim 6 or 7, characterized in that said frame (212) is formed wigh a large number of small holes (212b) in a portion of said frame facing said discharge air flow return passage.
References Cited (Backward Citations)
No citation records indexed.
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