An automatic variable transmnission, and a hydraulic pressure control system for the same, have a structure which can be installed in both rear and front wheel drive vehicles. The transmission includes: a torque converter which is connected to an output shaft of an engine and which converts and transfers torque from the engine; an input shaft connected to the output shaft of the torque converter; first and second planetary gearsets which are located between the input shaft and an output shaft; a first clutch which selectively locks a sun gear of the second planetary gearset to the input shaft; a second clutch which selectively locks the input shaft to the planetary pinion gear carrier of the first planetary gearset; a third clutch for selectively connecting the input shaft with a sun gear of the first planetary gearset; a first brake for selectively restricting the rotation of the sun gear of the first planetary gearset; a second brake for restricting rotation of both the ring gear of the second planetary gearset and the planetary pinion gear carrier of the first planetary gearset; and a one-way clutch to limit the rotational direction of the ring gear of the second planetary gearset and the planetary pinion gear carrier of the first planetary gearset.
A hydraulic control system includes a pressure/damper clutch controller, a pressure reducer, and a shift controller. The shift controller includes a manual valve indexed with a driver-controlled select lever to supply hydraulic pressure to the hydraulic pressure controller, the hydraulic pressure distributor, and the friction elements. The hydraulic pressure distributor includes a low control valve for supplying L-range pressure to another valve as control pressure in the low L range such that control pressure of the third pressure control valve is supplied to the first brake, an N-R control valve for supplying reverse pressure to the first brake by reduced pressure supplied via the pressure control valve when shifting into the reverse R range, a line pressure control switch valve controlled by D-range pressure and hydraulic pressure supplied to a second clutch, a first fail-safe valve controlled by control pressure supplied from the low control valve and from the second pressure control valve, a second fail-safe valve controlled by reverse pressure, hydraulic pressure supplied to a fourth clutch, and hydraulic pressure supplied to the third clutch, and an engine brake control switch valve for supplying D-range pressure to the fourth clutch in the first and third speeds of the drive D range.
A hydraulic control system in which hydraulic pressure generated pressure generated by an oil pump is supplied to a pressure/damper clutch controller, a pressure reducer, and a shift controller, wherein the pressure reduced by the pressure reducer and the hydraulic pressure supplied as a result of port conversion of the sift controller are supplied to the hydraulic pressure controller, and hydraulic pressure controlled by the hydraulic pressure controller is supplied to a hydraulic pressure distributor and directly to some friction elements.
Disclosed is a snowmobile including a reduction drive system including planetary gears. In an alternate embodiment, a reversing unit is provided. In a further alternate embodiment, an offset is provided in the drive system.
