Hydraulic power steering apparatus
US5439070A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1993 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Jun 11, 2013 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/45
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A power steering apparatus having a hydraulic pump for outputting a pressurized fluid, an assist force generation mechanism hydraulically connected to the pump through a supply passage to generate an assist force in response to rotation of a steering wheel, wherein the assist force generation mechanism has a characteristic that the back pressure thereof increases when the steering wheel is rotated. The power steering apparatus further comprises a flow control valve having a spool which is moved in response to a pressure drop at a metering orifice disposed in the middle of the supply passage, so as to control the flow rate of the pressurized fluid to be constant. The spring chamber of the flow control valve is connected to a reservoir through a drain passage, and a drain valve is disposed in the drain passage for allowing the flow of pressurized fluid from the spring chamber to the reservoir when the back pressure of the assist force generation mechanism is low, and for prohibiting the flow of the pressurized fluid when the back pressure of the assist force generation mechanism increases.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.