Hitachi, Ltd.

Shigenori Sato

Yukiji Iwase

Fumio Jyoraku

Sadashi Tanaka

Yoshitaro Ishii

Masao Sunagawa

Hisanori Toyoshima

Shinichi Shimode

Susumu Sato

Taiji Tajima

Shoji Hayashi

Kazuyuki Sugimura

Takayuki Sudou

Ryuji Ikeda

A vacuum cleaner includes a vacuum cleaner body in which a rotating brush, a dust collecting unit and an electric blower unit are integrally attached to a suction opening casing in which a brush chamber is formed. A rodlike handle is connected to the vacuum cleaner body. The rodlike handle is formed by a hollow member, and a plurality of batteries are arranged in series in the hollow member and are covered with a heat contraction tube.

Vacuum cleaner

A vacuum cleaner including an electric blower disposed inside a generally cylindrical rigid blower casing positioned inside the vacuum cleaner body. The blower casing has a lining of sound absorbing material and is configured to cause a swirling flow around inside the casing to an exit opening into a smoothly-curved transfer passage which curves away from the blower casing with a non-radial flow direction. The transfer passage curves circumferentially and axially and opens into an annular noise reduction space at the bottom of the cleaner body in which air is guided over a sound absorbing layer by smoothly arcuate guide ribs, vented through an aperture into an exhaust space between the bottom of the body and a caster base and escapes through a peripheral clearance around the caster base.

An electric blower has an electric motor, a centrifugal impeller rotating by the driving of the electric motor, an end bracket for separating the electric motor from the centrifugal impeller, and a diffuser. The diffuser includes a plurality of diffuser vanes arranged near the outer periphery of the centrifugal impeller, and a flat plate portion which extends between the centrifugal impeller and the end bracket for supporting the diffuser vanes. The flat plate portion has a plurality of guide vanes formed on an opposite surface thereof from the diffuser vanes. A passage is defined by the end bracket, the flat plate portion and the guide vanes so as to return the air flow, discharged from the centrifugal impeller through the diffuser vanes, inwardly of the blower. The end bracket is formed in a substantially convex shape so as to extend away from the flat plate portion of the diffuser, with the end bracket extending from a central portion toward its periphery, thereby defining an opening area of the discharge air flow return passage. A sound absorbing material is arranged in the discharge air flow return passage to absorb sounds from the discharging air flow.

Electric blower having improved return passage for discharged air flow

An acoustical absorbing material including a plurality of porous sheets and a plurality of high density sheets alternately superposed one over another and held together with contact with one another. At least one of the high density sheets is formed therein with one or more through-holes. The acoustical absorbing material of the above-mentioned construction exhibits a good acoustical absorption performance in a wide frequency range even if its thickness is not varied, and is effective in shutting off noises produced by electronic equipment, such as a computer.

Acoustical absorbing material

Growing community of inventors

Niihari, Japan

Shigenori Sato