Rotary valve for power steering gear
US5881771A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Apr 29, 1997 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Apr 29, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86662
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A low noise rotary valve for a hydraulic power steering gear that offers flexibility in the design of its boost characteristic has inlet ports to receive hydraulic fluid from a pump, return ports to return hydraulic fluid to the pump, and cylinder ports to communicate the hydraulic fluid to left and right-hand cylinder chambers of the hydraulic power steering gear. The valve has an input-shaft with a plurality of axially extending grooves separated by lands. A sleeve that has in its bore an array of axially extending slots that circumferentially align with the lands on the input-shaft is journalled on the input shaft. The interfaces between the coacting input-shaft grooves and sleeve slots define axially extending orifices which open and close when relative rotation occurs between the input shaft and the sleeve. These orifices are ported as a network such that they form primary and secondary hydraulic Wheatstone bridges each having right and left-hand inlet orifices and return orifices. When the input-shaft is rotated in relation to the sleeve, the flow of oil through the Wheatstone bridges creates a differential pressure between the right-hand and left-hand cylinder ports. The sid…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.