Power steering apparatus for a vehicle
US5471838A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1994 |
| Grant date | Dec 5, 1995 |
| Priority date | — |
| Expiry date | Mar 29, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB62D6/02
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A power steering apparatus for a motor vehicle is provided with a metering orifice arranged on a supply passage and a flow control device in parallel relation with the metering orifice. The flow control valve includes a spool and a spring and moves the spool against the force of the spring in response to the pressure difference across the metering orifice for returning an excess part of operating fluid discharged from an engine-driven pump to an intake side of the pump so as to keep the flow rate towards a power assist gear unit almost constant regardless of changes in rotational speed of the pump. A drooping device cooperating with the flow control valve is provided comprising a control orifice at the upstream of the metering orifice and a bypass valve in communication with a spring chamber of the flow control valve retaining the spring. When the pressure difference across the control orifice exceeds a predetermined value with the increase in the pump rotational speed to a predetermined speed, the bypass valve operates to drain the pressure in the spring chamber. The load acting on the pump is thereby relieved. A bypass control valve is responsive to the pressure at the downstream…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.