Hydraulic drive system for hydraulic working machine
US9249879B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 2011 |
| Grant date | Feb 2, 2016 |
| Priority date | — |
| Expiry date | Sep 2, 2032 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/7058
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A hydraulic drive system designed so that while maintaining intact a structure of a relief valve having a shockless function, the drive unit hydraulic drive system facilitates changing a driving pressure or braking pressure of a hydraulic swing motor and hence, changing a maximum driving torque or braking torque of the hydraulic swing motor. Inside a swing motor unit is arranged a first swinging relief valve provided with a shockless function to limit a driving pressure or braking pressure of the hydraulic swing motor in order to prevent the pressure from exceeding a first setting pressure. Also, a second swinging relief valve is provided for limiting the driving pressure or braking pressure of the hydraulic swing motor in order to prevent the pressure from exceeding a second setting pressure that is lower than the first setting pressure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.