Patent ID: 8151564
Filing Date: 2012-04-10
Classification: B62D

Abstract:
1. A method of hydraulic power steering, comprising the steps of monitoring pressure on each side of a piston in a steering gear; feeding a higher of the two pressures to a reference pressure circuit; sensing a drop in pressure in the reference pressure circuit to a low pressure limit and sensing a rise in pressure in the reference pressure circuit to a high pressure limit, closing a pressure switch upon the sensing of the drop in pressure to the low pressure limit to enable power to reach a clutch that engages a pump to trigger pumping by the pump, opening the pressure switch upon the sensing of the rise in pressure in the reference pressure circuit to a high pressure limit to stop the power from reaching the clutch and thereby disengage the clutch from the pump to stop the pumping by the pump; maintaining proportional pressure control between an input side of a steering valve in a valve manifold and the steering gear with a control valve in a valve manifold by maintaining a pressure differential between the input side of the steering valve and the steering gear during at least one event.