Abstract: A pressure reducing valve 20 is constructed such that a piston 22 is provided within a housing 21 provided with a primary port 28 and a secondary port 30 to form a primary pressure chamber 64 of a primary pressure P1 and a secondary pressure chamber 70 of a secondary pressure P2 which are connected to each other through an orifice 63. The piston 22 is subjected to the primary pressure P1 applied in one direction X1 in the axial direction and the secondary pressure P2 applied in the opposite direction X2 in the axial direction. A spring 23 exerts a force to the piston 22 in the direction X1. A back pressure chamber 55 is kept at the primary pressure P1 to cause the primary pressure P1 to be applied to the piston 22 in the opposite direction X2.

Abstract: A hydraulically operated power transmission apparatus transmits the output power from a power source at a selected speed ratio. The power transmission apparatus includes a casing having an opening in one end thereof, a base plate attached to the end of the casing in covering relation to the opening, the casing and the base plate jointly serving as a transmission case defining a closed space therein, a hydraulic pump having a pump drive shaft adapted to be operatively coupled to the power source, the hydraulic pump being disposed in the closed space, a hydraulic motor having a motor output shaft and drivable by a hydraulic pressure generated by the hydraulic pump, the hydraulic motor being disposed in the closed space, a pair of output shafts extending through the casing and the base plate, respectively, and disposed coaxially with each other, a differential mechanism disposed in the closed space and operable by the motor output shaft, the differential mechanism being coupled to the output shafts.