Title:
POWER TOOL
Document Type and Number:
WIPO Patent Application WO/2017/150030
Kind Code:
A1
Abstract:
Through the present invention, a portion of air from a fan is caused to flow back toward an inlet from a fan guide hole, the load on the fan is increased, and an increase in the speed of a motor during idling thereof is suppressed. A power tool having a fan guide 30 for straightening the flow of cooling air generated by a fan 25, wherein branching passages 35a through 35d are provided for causing a portion of the cooling air drawn into the fan 25 from a ventilation hole 31a to diverge from a flow toward an exhaust port formed on a bearing guide 40 side, and the portion of the cooling air flows toward an inlet and thereby circulates inside a housing. The branching passages 35a through 35d provided to the fan guide 30 are formed so as to be inclined in the same direction as a circumferential direction so that air channel resistance during actual operation (in an intermediate-speed region) does not increase. Through this configuration, flow channel resistance of the fan 25 during idling (in a high-speed region) is increased, and an increase in motor speed can be suppressed.
More Like This:
Inventors:
MATSUSHITA AKIRA (JP)
NISHIKAWA TOMOMASA (JP)
HORIE NORIYUKI (JP)
FUJIWARA MASAHIRO (JP)
NISHIKAWA TOMOMASA (JP)
HORIE NORIYUKI (JP)
FUJIWARA MASAHIRO (JP)
Application Number:
PCT/JP2017/002953
Publication Date:
September 08, 2017
Filing Date:
January 27, 2017
Export Citation:
Assignee:
HITACHI KOKI KK (JP)
International Classes:
B25F5/00; B24B23/02
Foreign References:
| JP2006315121A | 2006-11-24 | |||
| JP2015047668A | 2015-03-16 | |||
| JP2002103251A | 2002-04-09 | |||
| US20140331508A1 | 2014-11-13 |
Other References:
See also references of EP 3424647A4
Download PDF: