The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 20, 2008
Filed:
Mar. 08, 2005
Katsuhiro Oomori, Ibaraki, JP;
Atsushi Nakagawa, Ibaraki, JP;
Yasuyuki Ooe, Ibaraki, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
A power tool includes: a stator having a substantially cylindrical yoke and a plurality of permanent magnets that are firmly fixed to an inner surface of the yoke and circumferentially spaced from each other by a first gap; a rotor inserted inside the permanent magnets at a second gap radially; an outer frame portion that accommodates the stator and the rotor; a ventilation hole formed in the outer frame portion to place the first and second gaps in communication with an atmosphere; and a dustproof member comprising a ferromagnetic material, which is mounted in contact with the stator and has a protruding portion located in a passage going from the first and second gaps to the atmosphere via the ventilation hole.