To provide a hydrostatic continuously variable transmission of a work vehicle for shortening idling, by quickly raising the oil temperature of oil flowing in an HST.
This hydrostatic continuously variable transmission has two sets of a pair of hydraulic pump 8 and hydraulic motor 7 mutually connected by a closed circuit, and continuously variably shifts rotation of the hydraulic motor 7, and is constituted to return drain oil from residual ports T1 and T2 to an oil tank 17 by cooling via an oil cooler 18, by directly returning the drain oil from a partial port T3 to the oil tank 17 in a plurality of drain ports T1, T2 and T3 of the hydraulic pump 8 draining the drain oil including leakage oil of the hydraulic pump 8. For example, the drain oil of directly returning to the oil tank 17 is drained from one drain port T3 of setting a discharge quantity of the drain oil among the plurality of drain ports T1, T2 and T3 more than a discharge quantity of the drain oil from the other drain ports T1 and T2.
COPYRIGHT: (C)2007,JPO&INPIT
ARITA HIROYUKI
OSHIMA AKIO
