Abstract: A hydraulic continuously variable speed transmission includes means for detecting a speed reduction ratio of said continuously variable speed transmission, means for detecting an accelerator opening, and means for detecting vehicle speed. During running, when the means for detecting the accelerator opening detects that the accelerator opening has been fully closed, the means for detecting speed the reduction ratio detects the speed reduction ratio at the moment, and then an operation initiating vehicle speed of said clutch valve is determined based on the detected speed reduction ratio, and when the vehicle speed detected by the means for detecting vehicle speed is reduced to the operation initiating vehicle speed, the clutch valve starts to open.

Abstract: A hydraulic continuously variable speed transmission includes a hydraulic pump and a hydraulic motor, at least one of said hydraulic pump and motor being of variable displacement type. A hydraulic path is formed in a member of the pump which rotates in synchronism with an output shaft of engine, for communicating hydraulic a pressure chamber of the hydraulic pump with a drain. A check valve is provided in the hydraulic path for closing the hydraulic path under centrifugal force created by the rotation of the member when this member is in rotation faster than a predetermined speed, and for opening the hydraulic path against a centrifugal force when the member is in rotation slower than the predetermined speed.

Abstract: A hydraulic servo cylinder device for controlling a speed reduction ratio or clutch operation in a continuously variable transmission comprises cylinder and a piston slidably fitted in a cylinder chamber of the cylinder. The cylinder chamber is divided by the piston into a rod-side cylinder chamber and a head-side cylinder chamber, the rod-side cylinder chamber being supplied with a hydraulic line pressure, the head-side cylinder chamber being supplied with a hydraulic control pressure. When the piston is moved to a position near a head-side stroke end, the control pressure in the head-side cylinder chamber is so set that a hydraulic force which the piston receives from said control pressure is in equilibrium with a hydraulic force which the piston receives from the line pressure.

Abstract: A hydraulically operated swash-plate apparatus includes a cylinder block rotatably supported in a case and having a plurality of axial cylinders arranged in an annular pattern, the case having an end plate for bearing a thrust load from the cylinder block, a plurality of plungers received respectively in the cylinders, a swash plate supported in the case by trunnions and slidably held against the free ends of the plungers, an actuator for tilting the swash plate, the plungers being movable into and out of the respective cylinders by a stroke which is variable according to the angle of inclination of the swash plate, a support member by which the trunnions are rotatably supported, and a tension member coupling the end plate and the support member to each other. The apparatus also includes a stopper mounted in the case for engaging a back of the swash plate to limit the maximum angle of inclination of the swash plate.

Abstract: An engine throttle valve control apparatus whereby a reference throttle valve degree of the opening is established in accordance with the accelerator pedal actuation position and a reference opening degree characteristic. A boundary throttle valve degree of the opening is established in accordance with the accelerator pedal actuation position and at least one upper limit opening degree characteristic and a lower limit opening degree characteristic. A target degree of the throttle opening is computed from the relationship between the reference degree of the opening and a boundary degree of the opening, in conjunction with the contents of a characteristic command which can be freely selected. Thereby throttle valve is driven to reduce the deviation between the actual degree of the opening and the target degree of the opening.

Abstract: A throttle valve control apparatus for a vehicle engine, whereby a reference degree of opening of the throttle valve is derived based on the accelerator pedal actuation position and is then corrected in accordance with vehicle operating conditions to obtain a target degree of opening of the throttle valve. An upper limit opening degree and a lower limit opening degree of the throttle valve are also derived, and if the target opening degree, which is obtained on the basis of the vehicle operating conditions, is found to be greater than the upper limit opening degree, then the upper limit opening degree is used as the target opening degree. Similarly, if the target opening degree, which is determined from the vehicle operating conditions, is less than the lower limit opening degree, then the lower limit opening degree is used as the target opening degree.