Patent attributes
A hydrostatic continuously variable transmission includes a swash plate type plunger hydraulic pump and a swash plate type plunger hydraulic motor connected via a hydraulic closed circuit, an inclined angle of a swash plate of the hydraulic motor is variably controlled for continuous shift control. A lock-up mechanism closes the hydraulic closed circuit to make lockup executed when the quantity of oil that flows from the hydraulic pump into the hydraulic motor decreases according to variable control over the inclined angle of the swash plate. The input rotation of the hydraulic pump and the output rotation of the hydraulic motor are substantially synchronous. The lock-up mechanism is operated when lockup control oil pressure is applied and closes the hydraulic closed circuit. A lockup control oil passage that supplies the lockup control oil pressure is provided with an opening opened and closed according to the inclination of the swash plate.
