A damper valve for a hydraulic power steering device is disposed in a hydraulic oil circuit connecting an oil passage changing-over valve in a gear box and left and right oil chambers of a power cylinder. It is provided with a piston valve which is opened by through-flow of hydraulic oil returned back to the oil passage changing-over valve from either one of the left and right chambers of the power cylinder, and a check valve which is disposed in a valve body of the piston valve and which allows only hydraulic oil supplied from the oil passage changing-over valve to either one of the left and right chambers of the power cylinder to flow through the check valve. The piston valve is structured such that a throttle oil passage is formed by through flow of the returned hydraulic oil having an oil pressure of a predetermined value or less, and a fully opened oil passage is formed by through flow of the returned hydraulic oil having an oil pressure of more than the predetermined value. Oil passages for the returned-back hydraulic oil are formed in the valve body of the piston valve.
The invention concerns a hydraulic power-assisted steering system for motor vehicles, with a valve and two hydraulic lines leading from the valve to cylinders of a servo drive mechanism and with at least one steering damper, the steering damper having a basic body 4 which is arranged movably along a path in a working chamber 3 and delimits with an outer wall 2 of the working chamber 3 a first channel through which hydraulic fluid can flow.
An air vent mechanism includes a composite type air vent valve having a check valve for controlling a pressure in a fuel tank and a cut valve for discharging vapor in the fuel tank and preventing fuel from leaking. The check valve and the cut valve are connected through a communicating path. A tank side connecting portion communicates with the communicating path, and an atmosphere side connecting portion communicates with an atmosphere side port of the check valve portion.
A fuel blocking valve device includes a housing attached to a fuel tank of a vehicle and having a communication path between an inside and an outside of the fuel tank, a float valve for closing the communication path when fuel flows into the housing, and a two-way valve disposed above the float vale for opening and closing according to an inner pressure of the tank. The two-way valve opens and closes according to a difference between the inner pressure of the fuel tank and an atmospheric pressure. Further, the two-way valve includes a valve member for opening when the vehicle runs and vibrates. The valve member is formed of a spherical member and a cone shape valve seat for opening the communication path when the inner pressure of the fuel tank exceeds a predetermined high level.
A casing accommodates therein a movable valve adapted to be moved away from a valve seat by a hydraulic oil flowing through an oil-hydraulic circuit from a hydraulic cylinder to an oil-hydraulic pump. In an event of oscillatory hydraulic pressures in the hydraulic cylinder, the hydraulic oil is returned through the oil-hydraulic circuit from the hydraulic cylinder to the oil-hydraulic pump via a second port, a communication path, a minor gap between the movable valve and the valve seat, and a first port. In this process, the communication path allows for a smooth flow of the hydraulic oil from the second port into the movable valve.
