Hydraulic drive system and valve apparatus
US5251444A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1991 |
| Grant date | Oct 12, 1993 |
| Priority date | — |
| Expiry date | Oct 16, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/6052
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A valve apparatus (30) of a hydraulic valve system has a plurality of directional control valves (78, 79) that control the flow of the hydraulic fluid to a plurality of actuators (34, 35). Check valves (59, 60) are provided for taking out, as a first control pressure, a maximum load pressure among load pressures of the plurality of actuators, first pressure generating devices (89, 91) for generating second control pressures different from the first control pressure, and second pressure generating devices (90, 92) for generating third control pressures different from said first and second control pressures. Flow control valves (36, 39) control flow rates of the hydraulic fluid passing between supply passages (42, 43) and first passages (44, 45) dependent upon openings of variable restrictors (52, 53; 54, 55) disposed therebetween, and also for selectively communicating between second passages (50, 51) and load passages (46, 47; 48, 49), and pressure control valves (70, 71) disposed between the first passages and the second passages for controlling pressures inside the first passages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.