Auxiliary hydraulic pump system
US5201174A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1991 |
| Grant date | Apr 13, 1993 |
| Priority date | — |
| Expiry date | Dec 2, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB62D5/30
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
An engine-driven pump supplies pressurized hydraulic fluid to vehicle brake and steering circuits. A ground driven variable displacement pump controlled by a control circuit is de-stroked when the engine-driven pump is operational. The variable displacement pump includes a movable piston which divides a bore into a pilot chamber and a pump chamber. An outlet line with a check valve communicates fluid one way from the pump chamber to the vehicle circuits. An inlet line with a check valve communicates fluid one way from a reservoir to the pump chamber. A ground-driven rotatable cam member reciprocates the piston. A spring urges the piston towards the cam member and towards a full stroke position. A pilot line which communicates fluid pressure from an outlet of the engine-driven pump to the pilot chamber. When the engine-driven pump is operational the pressure in the pilot line moves the piston away from the cam member, thus de-stroking the variable displacement pump. When the engine-driven pump stops, the pilot pressure drops, causing the variable displacement pump to go into stroke. A relief valve may be used to reduce the stroke of the variable displacement pump when its output pre…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.