Responsive pilot-operated control valve for front wheel drive
US4099588A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 1, 1976 |
| Grant date | Jul 11, 1978 |
| Priority date | — |
| Expiry date | Sep 1, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/8663
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A pilot-operated, spring-centered, directional control valve includes a valve body having a bore, chambers at opposite ends of the bore, a valve spool slidably disposed within the bore, a hollow piston slidably disposed within each of the chambers and biased by springs inwardly toward the spool, and a secondary piston slidably disposed within one of the primary pistons so that pilot pressure directed into the outward ends of the chambers acts on the end of the spool or the end of the secondary piston to selectively operate the valve. The various components of the valve have differing effective cross-sectional areas upon which pilot pressure acts. The control valve is advantageously employed in a hydraulic system controlling front wheel drive in a vehicle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.