Abstract: A hydraulic control system for an internal combustion engine, includes a driven mechanism driven by hydraulic pressure fed through a flowing passage change-over valve. The flowing passage change-over valve includes a valve body formed with a plurality of ports which are respectively communicated with the supply passage and the oil passage, and a spool valve body slidably disposed in the valve body to open and close the plurality of ports, the ports including a supplying port communicated with the supplying passage. The maximum cross-sectional area of the supplying port is larger than a minimum cross-sectional area of the supplying passage. The flowing passage change-over valve is supplied with electric current to heat hydraulic fluid kept in the flowing passage change-over valve so as to lower a viscosity of the hydraulic fluid.

Abstract: A hydraulic control system for an internal combustion engine, includes a driven mechanism driven by hydraulic pressure fed through a flowing passage change-over valve. The flowing passage change-over valve includes a valve body formed with a plurality of ports which are respectively communicated with the supply passage and the oil passage, and a spool valve body slidably disposed in the valve body to open and close the plurality of ports, the ports including a supplying port communicated with the supplying passage. The maximum cross-sectional area of the supplying port is larger than a minimum cross-sectional area of the supplying passage. The flowing passage change-over valve is supplied with electric current to heat hydraulic fluid kept in the flowing passage change-over valve so as to lower a viscosity of the hydraulic fluid.

Abstract: A feed-screw unit includes a rotor formed with a female screw, and a reciprocating shaft disposed inside the rotor to be moved forward and backward in the axial direction of the rotor in accordance with rotation thereof. The reciprocating shaft includes a male screw with a first portion to be in engagement with the female screw of the rotor and a second portion to be in non-engagement therewith.

Abstract: A rear wheel steer control method and apparatus for a four wheel steer vehicle executes an opposite phase steer control on the basis of detected values of a front wheel steer angle sensor and a vehicle speed sensor during a low vehicle speed. The opposite phase steering is stopped for a predetermined distance from a start of straight running, then the rear wheel steer angle is controlled by a primary delay control. When the front wheel steer angle is decreased, the primary delay control is stopped in a predetermined condition. Therefore, the four wheel steer vehicle gives a smooth steer feeling to a driver in every driven condition.

Abstract: In an actuating apparatus applicable to an actuation of a valve installed in an intake air passage of an internal combustion engine, a first magnetic circuit (D.sub.1) is formed with a stationary member (A) and with a part of a driven member (B), the driven member being disposed within the stationary member so as to be linearly or angularly displaced, and a second magnetic circuit (D.sub.2) is formed in the stationary member and another part of the driven member so as to be branched from the first magnetic circuit, a strength of a magnetic flux flowing through the second magnetic circuit being the same as that of a magnetic flux flowing through the first magnetic circuit and a direction of the magnetic flux flowing through the second magnetic circuit being opposite to that of the magnetic flux flowing through the first magnetic circuit.

Abstract: A power transmission comprises a first coil spring wound to a casing and a first drum and having the diameter to be extended by rotation of an internal gear in one direction, a second coil spring wound to the casing and a second drum and having the same winding direction as the first coil spring and the diameter to be extended by rotation of the internal gear in the other direction, and cylinder members arranged on outer peripheries of the first and second coil springs for serving to restrict extension of the diameter of the first and second coil springs, the cylinder members being rotatable relative to the internal gear.

Abstract: An apparatus for steering rear wheels of a four-wheel steering vehicle is provided. This apparatus includes a first housing which has an operating rod displaceable along the longitudinal center line thereof for steering the rear wheels, a second housing which has a cam rotatably supported thereby for displacing the operating rod in a desired direction, a movable block engaging with the cam, and a stationary block mounted on the operating rod. The movable block moves along a guide rod provided in the second housing according to rotation of the cam. The stationary block transmits the movement of the movable block to the operating rod at a first angular position between the guide rod and the operating rod and blocks the transmission of the movement of the movable block at a second angular position different from the first position.

Abstract: An electrostatic capacity-type stroke sensor is designed for measuring relative displacement between a cylindrical member and a rod member. The electrostatic capacity-type stroke sensor includes a conductive cylinder arranged coaxially to the cylindrical member and fixed to one of the cylindrical member and the rod member for movement therewith. An annular member movable with either the cylindrical member or the rod member and made of a dielectric material is provided opposite the conductive cylinder. The conductive cylinder and the dielectrical annular member are coupled for creating electric capacity magnitude which is variable depending upon the relative position thereof. The conductive cylinder and the dielectric annular member are arranged for relative movement according to relative movement of the cylindrical member and the rod member so that the electrostatic capacity is variable depending upon the relative position of the cylindrical member and the rod member.

Abstract: In order to ensure a reliable body earth and insulate a capacitance type position sensor from external noise, an electrically conductive tube is insulatingly mounted within an electrically conductive housing. The capacitance developed between the tube and a piston rod which is reciprocally arranged therein is measured while the rod and the conductive body are electrically connected. By soundly grounding the rod a secure ground for the housing is established.