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:
Feb. 14, 2017
Filed:
Aug. 28, 2014
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Shinya Imura, Toride, JP;
Kouji Ishikawa, Kasumigaura, JP;
Hidetoshi Satake, Ishioka, JP;
Shinji Nishikawa, Kasumigaura, JP;
Tomoaki Kaneta, Kasumigaura, JP;
Shiho Izumi, Hitachinaka, JP;
HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo, JP;
Abstract
A work machine prevents a fault in a swing electric motor if an uneven coil temperature increase occurs in the swing electric motor during swing press and related operations. An electricity storage device is connected to the electric motor. An inverter drives the electric motor and a swing control lever issues a command to drive the swing structure. A rotational speed detecting device detects swing speed of the swing structure and a controller controls torque of the electric motor. The controller reads the swing speed of the swing structure detected by the rotational speed detecting device to control such that, when the swing speed is zero, the torque of the electric motor is smaller than a maximum torque value and, when the swing speed is a first rotational speed higher than zero, the torque of the electric motor is the maximum torque value.