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. 06, 2001
Filed:
Mar. 07, 1997
Yasunori Ohkura, Kawasaki, JP;
Hikosaburo Hiraki, Oyama, JP;
Noboru Kanayama, Ninomiya-machi, JP;
Ryutaro Makida, Kawasaki, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
The present invention relates to a speed changing device for a hydraulic driving apparatus and a speed change control method thereof, which provide excellent controllability, traveling efficiency, and reliability without occurrence of cavitation. To this end, the device comprises a shifter selected position sensor (,) for detecting a shift lever change, a motor rotational speed sensor (,) for detecting a rotational speed of a hydraulic motor (,), and a control device (,); and the control device (,) judges and controls either a powering control or a brake control, based on the change of the shift lever selection and on the comparison of the detected motor rotational speed with a memorized motor rotational speed. In addition, a two-stage back pressure valve (,) can be provided between a directional control valve (,) and an oil tank.