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:
Jul. 07, 2015
Filed:
Jun. 17, 2011
Nobuo Uzawa, Nagareyama, JP;
Mitsugu Ojima, Tsuchiura, JP;
Kouji Ishikawa, Kasumigaura, JP;
Hidetoshi Satake, Ishioka, JP;
Nobuo Uzawa, Nagareyama, JP;
Mitsugu Ojima, Tsuchiura, JP;
Kouji Ishikawa, Kasumigaura, JP;
Hidetoshi Satake, Ishioka, JP;
HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo, JP;
Abstract
A reduction gear is mounted on a revolving frame, and an electric motor having an electric motor shaft is disposed on the reduction gear. A hydraulic motor having a shaft is disposed on an upper side of the electric motor. A shaft insertion hole through which an upper end side of the electric motor shaft is inserted is provided in a lid portion of an electric motor casing. A male spline portion provided on the hydraulic motor shaft is spline-coupled to a female spline portion provided on the electric motor shaft. A bearing is provided between the shaft insertion hole and the electric motor shaft, and a pressure tight seal is provided by being located upwardly of the bearing. Hence, spline coupling portions of the female spline portion and the male spline portion are constantly lubricated by making use of drain oil which has leaked from the hydraulic motor.