Dual-pump, flow-isolated hydraulic circuit for an agricultural tractor
US5918558A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 1, 1997 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Dec 1, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/7142
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic circuit has first and second pumps coupled to first and second directional valves, each controlling work mechanisms such as a hydraulic cylinder and a hydraulic motor. The directional valves are in a valve assembly having a fluid passage through it. The passage includes first and second input ports and a passage closure intermediate the ports to prevent cross-feeding of the pumps. The first valve is connected to the passage between the first port and the closure and the first pump flows fluid to the first port. Similarly, the second valve is connected to the passage between the second port and the closure and the second pump flows fluid to the second port. In a more-specific embodiment, the second pump is a variable displacement pump and the first pump is a fixed displacement pump also connected to a power steering system through a priority valve. Thus, the first pump flows fluid to the power steering system as well as to the first port.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.