Closed circuit energy recovery system for a work implement
US7325398B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 5, 2004 |
| Grant date | Feb 5, 2008 |
| Priority date | — |
| Expiry date | Jan 26, 2025 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2217
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A closed circuit hydraulic system includes a fluid reservoir, a hydraulic cylinder having a cylinder rod, a bidirectional variable displacement hydraulic pump that pumps fluid to either extend or retract the cylinder rod on demand, a flow control valve for relieving pressure between the variable displacement hydraulic pump and the cylinder, and a low pressure check valve between the variable displacement hydraulic pump and the fluid reservoir. Also included is a charge pump for charging the variable displacement hydraulic pump and an accumulator for saving extra energy and fluid from the hydraulic cylinder during the retraction of an extended cylinder rod and using that fluid and energy during the extension of the hydraulic cylinder to reduce a load on the charge pump. The flow control valve opens on demand to allow floating. The low pressure check valve opens when pressure at an inlet of the variable displacement hydraulic pump is low to provide additional fluid and pressure so as to avoid cavitation. A method for using the closed circuit hydraulic system is also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.