Patent ID: 6988362

Claim:
A hydrostatic stepless transmission, comprising: a hydraulic pump and a hydraulic motor, at least one of the hydraulic pump and motor being variable in displacement; a closed circuit for fluidly connecting the hydraulic pump and motor to each other therethrough, the closed circuit including a pair of oil passages between the hydraulic pump and motor, one of the oil passages being hydraulically higher-pressured and the other being hydraulically depressed when the hydraulic pump delivers oil to the hydraulic motor; a speed change operation device for changing output rotational speed of the hydraulic motor; and a leak valve interlocking with the speed change operation device, wherein the leak valve is connected to the closed circuit so that, when the speed change operation device is suddenly operated, the leak valve allows oil to leak from the higher-pressured oil passage to an area hydraulically pressured lower than the higher-pressured oil passage, and then stops oil leakage when operation of the speed change operation device is stopped.