Servo-control valve for a linear hydraulic motor
US4211147A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1977 |
| Grant date | Jul 8, 1980 |
| Priority date | — |
| Expiry date | Jun 30, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86445
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A servo-control valve for a linear hydraulic motor wherein the control valve piston is isolated from the side loading of a cam and roller by employing a cam follower plunger, as a separate detached element coaxial with the piston. The valve piston and the cam follower plunger are maintained in intimate contact due to the constant back pressure applied by the hydraulic system. The plunger is encased in a cylindrical array of balls which are preloaded between the plunger and the piston chamber walls such that the plunger experiences essentially only rolling friction, but no sliding friction, as the plunger moves. This form of preloading of the balls eliminates the backlash associated with clearance around the plunger.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.