Fluid pressure control valve for hydraulic actuator
US4651776A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1986 |
| Grant date | Mar 24, 1987 |
| Priority date | — |
| Expiry date | Feb 28, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86734
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A fluid pressure control valve for a hydraulic actuator has a valve body having a valve bore and a fluid port for discharging a fluid toward the hydraulic actuator, and a spool slidably received in the valve bore. The spool has a cylindrical spool section slidably fitted in the valve bore for closing the fluid port and a tapered spool section having a conical shape for opening the fluid port through annular open clearance of a variable area between the concial surface of the spool and the cylindrical surface of the valve bore. Between the cylindrical ad tapered spool sections, there is formed an annular groove or an annular face forming a step for preventing particles of dust suspended in the fluid from being bitten between the tapered spool section and the cylindrical surface of the valve bore by traping the particles. Furthermore, a radial groove is formed in a side wall of the fluid port in order to prevent a sudden change in the opening area which would be otherwise caused by an abrupt change of the spool contour due to the annular groove or the annular face.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.