Bootstrap power steering systems
US5435698A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 29, 1993 |
| Grant date | Jul 25, 1995 |
| Priority date | — |
| Expiry date | Jul 29, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K7/14
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
Methods and devices for enhancing bootstrap hydraulic systems for use in vehicular power steering systems are disclosed. Improved pressure dividing networks are provided for enabling balanced operation of supply pressure control function when valve input shaft and sleeve are in relative centered positions or for enabling a first method of providing speed sensitive control of steering assist. Control valves utilizing a combination of open-center and closed-center flow control orifices are provided for reducing parasitic pressure losses. An improved variable displacement pump is provided for enabling volumetric flow rate efficient operation of bootstrap systems. A vehicular speed dependent command signal for a servo motor powered bootstrap hydraulic system is utilized in another method of providing speed sensitive control of steering assist. Control valves using parasitic and bypass slots having decreasing overall flow resistance over a meaningful portion of nominally closing motion of a host control valve are disclosed wherein methods of providing nominally linear control valve pressure-effort characteristics of the meaningful portion of nominally closing motion of the host control …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.