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:
Jan. 07, 2020
Filed:
Nov. 27, 2015
Applicant:
Hitachi Koki Co., Ltd., Tokyo, JP;
Inventors:
Assignee:
KOKI HOLDINGS CO., LTD., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B25F 5/00 (2006.01); B25B 23/147 (2006.01); B25B 21/02 (2006.01); B24B 23/02 (2006.01); H02P 6/18 (2016.01); H02P 6/24 (2006.01); H02P 6/06 (2006.01); B25B 23/04 (2006.01); B25B 21/00 (2006.01); H02K 7/14 (2006.01); H02P 6/08 (2016.01); H02P 29/02 (2016.01);
U.S. Cl.
CPC ...
B25F 5/00 (2013.01); B24B 23/028 (2013.01); B25B 21/02 (2013.01); B25B 23/147 (2013.01); B25F 5/001 (2013.01); H02P 6/18 (2013.01); H02P 6/24 (2013.01); B25B 21/004 (2013.01); B25B 23/045 (2013.01); H02K 7/145 (2013.01); H02P 6/06 (2013.01); H02P 6/08 (2013.01); H02P 29/02 (2013.01);
Abstract
In order to provide an electric tool with good operability that can extend the life of and suppress breakage of a switching element for controlling energization of a brushless motor, a control unit (), after an operation switch () is turned off, does not immediately turn off an inverter circuit () (does not set the duty of a PWM signal to 0), and instead normally operates the inverter circuit () with a low-duty PWM signal and waits until a rotation speed of a brushless motor () reaches a predetermined rotation speed or less to turn off the inverter circuit () (to set the duty of the PWM signal to 0).