Abstract: A flow control device or valve used in a power steering system of an automotive vehicle. The flow control device comprises a housing formed with an axially extending hole in which a spool valve is movably disposed. A first pressure chamber is defined in the hole, with one end of the spool valve. A drain passage is opened to the first pressure chamber and closable with the spool valve. A second pressure chamber is defined in the hole, with the other end of the spool valve. A restricting orifice is provided to be communicated with the first pressure chamber. An introduction passage is formed to be communicated through the restricting orifice with a discharge passage and opened to the first pressure chamber. The pressure in the discharge passage is introduced to the second pressure chamber. A first spring is disposed in the second pressure chamber to bias the spool valve in a direction to close the drain passage. A spring holding member is movably and coaxially disposed in the axially extending hole.

Abstract: In a flow control valve, a valve spool is movable for variably controlling an opening area of a port portion of a drain passage so that a necessary flow rate of fluid is conducted from a first pressure chamber to an outlet passage through a control orifice while a surplus flow rate of fluid is returned from the first pressure chamber to the drain passage. A movable sleeve is installed in a valve spool accommodation hole and around the valve spool. The movable sleeve has through holes communicable with the drain passage and an inlet passage, respectively. The movable sleeve has a first axial end portion disposed in the first pressure chamber and a second axial end portion disposed in a low pressure chamber. A spring is disposed in the low pressure chamber for urging the movable sleeve toward the first pressure chamber side.

Abstract: A gear train of a rear wheel steering arrangement for an automotive vehicle includes a worm gear which is driven by a motor to steer rear wheels. The worm gear is designed to exhibit a reverse rotation efficiency more than zero so that when reverse torque is transmitted from a worm wheel to a worm, the worm is allowed to rotate in a reverse direction.

Abstract: A connecting arrangement for an automotive rear wheel steering unit is provided which is adapted for connecting an output shaft of a rear wheel steering gear train and a steering rod for steering rear wheels. The connecting arrangement includes a tapered portion formed on the output shaft, a tapered bore formed in the steering rod for receiving the tapered portion, and a fastener for locking the tapered portion of the output shaft to the tapered bore of the steering rod. With these arrangements, easy connecting operation is established with high mounting accuracy.

Abstract: An electric motor drive-type power steering system includes a steering gear, a first motor constantly connected to the steering gear for supplying thereto a steering assist force, and a second motor connectable to the steering gear by way of an electromagnetic clutch for selectively supplying a steering assist force to the steering gear in addition to the steering assist force by the first motor. The first and second motors and the electromagnetic clutch are controlled so that both of the first and second motors are put into action when the vehicle speed is lower than a predetermined value and only the first motor is put into action when the vehicle speed is higher than the above mentioned predetermined value. The first motor is of a smaller maximum output type as compared with the second motor.

Abstract: A rear wheel steering mechanism is disclosed in which an eccentric shaft drivingly connected to an electric motor includes an eccentric portion, a motion transmitting body is connected to a rod assembly in longitudinal fit manner, and a spherical joint whereby eccentric motion of said eccentric portion in response to rotational motion of the eccentric shaft causes said motion transmitting body to impart at least a reciprocal motion to said rod assembly.