Adjustable relief valve arrangement for a motor vehicle power steering hydraulic pump system
US5651665A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1996 |
| Grant date | Jul 29, 1997 |
| Priority date | — |
| Expiry date | Nov 12, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04B49/24
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A hydraulic pump having a flow control valve for recirculating a fraction of the discharge of a rotating group of the pump and an externally adjustable pressure relief valve. The flow control valve includes a cylindrical bore in a housing of the pump, a discharge passage intersecting the bore, a recirculation passage intersecting the bore, and a valve spool slideable in the bore. A valve body on the housing closes an open end of the cylindrical bore and cooperates with the valve spool in defining a spring chamber connected to the discharge passage. A spring in the spring chamber biases the valve spool to a position corresponding to zero recirculation. The relief valve includes a stepped bore in the valve body, a valve seat in the stepped bore, a valve element, a spring biasing the valve element against the valve seat, and a spherical metal spring seat interference fitted in the stepped bore. The spherical spring seat is plunged into the stepped bore while the pump is operating to compress the relief valve spring until a reaction force of the relief valve spring on the relief valve element induces a preselected pump relief pressure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.