Patent ID: 7401465
Filing Date: 2008-07-22
Classification: F15B,F16H

Abstract:
1. A vehicle hydraulic system comprising: a higher pressure pump for supplying pressurized fluid to a higher pressure circuit via a first supply line; and a lower pressure pump for supplying pressure fluid to a lower pressure circuit via a second supply line; a control valve controlling communication between the high pressure circuit and a reservoir; a pressure regulating relief valve having an inlet connected to the first supply line, an outlet connected to the second supply line and a pressure sensing port communicated with the first supply line, the relief valve opening when a demand of the higher pressure circuit is satisfied and supplying fluid from the first supply line to the second supply line at a pressure lower than the pressure produced by the higher pressure pump; and a control unit for controlling the control valve as a function of operation of the high pressure circuit, the control valve having an inlet communicated with the high pressure circuit, an outlet communicated with a reservoir and a valve member, the valve member having a first position herein the inlet is freely communicated with the outlet, and having a second position wherein the inlet is communicated with the outlet via an orifice.