Apparatus for use in turning steerable vehicle wheels
AssigneeTRW Automotive U.S. LLC
InventorBruce C. Noah
Life of this patent
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Abstract
An apparatus (10) for use in turning steerable vehicle wheels (14, 16) includes a hydraulic power steering motor (12). A pump (26) is connected in fluid communication with the hydraulic power steering motor (12) by a supply conduit (30). A continuously variable transmission (50) is connected with the engine (52) of the vehicle and with the pump (26). The continuously variable transmission (50) is operable under the influence of force transmitted from the engine (52) to drive the pump at a first speed when the flow of fluid from the pump (26) is at a first level. The continuously variable transmission (50) drives the pump (26) at a second speed different than the first speed when the flow of fluid from the pump is at a second level different than the first level.
Claims14
An apparatus for use in turning steerable vehicle wheels comprising:
- a hydraulic power steering motor connected with the steerable vehicle wheels and operable to turn the steerable vehicle wheels,
- a pump connected in fluid communication with said hydraulic power steering motor by a supply conduit and operable to supply hydraulic fluid to said hydraulic power steering motor during turning of the steerable vehicle wheels, and
- a continuously variable transmission connected with the engine of the vehicle and with said pump, said continuously variable transmission being operable under the influence of force transmitted from the engine of the vehicle to drive said pump at a first speed when the flow of fluid from said pump is at a first level, said continuously variable transmission being operable under the influence of force transmitted from the engine to drive said pump at a second speed different than said first speed when the flow of fluid from said pump is at a second level different than the first level, said first speed at which said pump is driven by said continuously variable transmission is greater than said second speed at which said pump is driven by said continuously variable transmission.
A vehicle steering system comprising:
- a hydraulic power steering gear including a hydraulic motor operatively connectable with steerable vehicle wheels for, when connected with the vehicle wheels, steering the vehicle wheels,
- a hydraulic fluid reservoir,
- a fixed displacement pump having an inlet port for fluid communication with said reservoir and an outlet port for fluid communication with said steering gear through a supply conduit,
- a continuously variable transmission for driving said fixed displacement pump, said continuously variable transmission including a first input driven by the vehicle engine and a second input controlled by a pressure differential across a fixed orifice in said supply conduit, said first and second inputs causing said fixed displacement pump to be driven at a speed to produce a desired hydraulic fluid flow for steering the vehicle wheels.
Dependencies are inferred from the claim text.