Patent ID: 7941998

Claim:
A hydrostatic continuously variable transmission configured by connecting a swash plate type plunger hydraulic pump and a swash plate type plunger hydraulic motor via a hydraulic closed circuit and configured to enable variably controlling of an inclined angle of a swash plate of at least either of the hydraulic pump and the hydraulic motor, shifting the input revolution speed of the hydraulic pump and acquiring the output revolution speed of the hydraulic motor, the hydrostatic continuously variable transmission comprising: a lock-up mechanism that closes the hydraulic closed circuit to make lockup executed when the quantity of oil that flows from the hydraulic pump into the hydraulic motor via the hydraulic closed circuit decreases according to a variable control over the inclined angle of the swash plate and the input rotation of the hydraulic pump and the output rotation of the hydraulic motor are substantially synchronous; wherein the lock-up mechanism is configured to enable being operated when lockup control oil pressure is applied and closing the hydraulic closed circuit, said lock-up mechanism includes a motor eccentric member rockably attached on an end of a motor casing, said motor eccentric member being in the shape of a ring with a motor side cam ring being arranged on an inside face of said ring; and a lockup control oil passage for supplying the lockup control oil pressure is provided with an opening opened and closed according to the inclination of the swash plate and is formed to enable closing of the opening when an inclined angle of the swash plate is in the vicinity of a lock-up angle at which the input rotation of the hydraulic pump and the output rotation of the hydraulic motor are substantially synchronous.