Abstract: There is provided a circulation line (39) for circulating pressurized oil from an accumulator (11) into a housing (15) of a steering valve (14). An orifice joint (41) is provided along the path of the circulation line (39). The orifice joint (41) is removably mounted on the housing (15) of the steering valve (14) from outside. An orifice portion (42) of the orifice joint (41) applies a throttling function to the circulating oil liquid whereby a frictional heat is generated therein. The oil liquid in a warm state flows through a communication passage (21), passages in a spool valve (16), and a low pressure side passage (18B), thus enabling the steering valve (14) to be always in a warm state.

Abstract: In a power unit comprising an engine (13) and an HST (24) which are formed into an integral body, a lubricating oil for use in the engine and an operating oil of the HST (24) are commonized. After being cooled, the common oil is fed from the side of the engine (13) to the HST (24). Such arrangement suppresses the drop in viscosity of the common oil and prevents the drop in efficiency and the occurrence of seizing on the side of the HST (24).

Abstract: An HMT apparatus (T) is mounted on a vehicle (A). In the HMT apparatus (T), input rotational force from an engine (13) is once divided into two systems which are then transmitted by an MT device (23) and by an HST device (24) respectively and are re-synthesized for transfer toward wheels (12) and (16). The HMT apparatus (T) is disposed on the vehicle-body right side of the engine (13) which is sideways-mounted on a vehicle body (1), and its input and output shafts (25) and (26) are disposed in parallel with a crank shaft (13a) of the engine (13) and are disposed to run parallel with each other. The input shaft (25) is coupled directly to the crank shaft (13a) and an input gear (27) of the MT device (23) is mounted on the input shaft (25), and a hydraulic piston pump (30) of the HST device (24) is connected to the right side end of the input shaft (25).