GETRIEBE FUER EIN FAHRZEUG MIT VIERRAD-ANTRIEB

摘要

A driving free distribution transmission for use with a vehicle with fourwheel drive. The vehicle has first and second drive shafts which are connected with the front and rear wheels, respectively. The transmission has a hydraulic clutch, a differential pump, a bias spring, and a selector valve. The clutch has outer and inner plates which are caused to frictionally engage with each other to transmit rotary power between the two drive shafts. The pump produces a hydraulic pressure corresponding to the difference between the rotating speeds of the drive shafts. The oil delivered by the pump is forced into a reservoir through a first passage in which a restrictor is formed. A second passage connects the pump with an oil chamber in the clutch. A third passage connects the oil chamber with the reservoir without via the restrictor. The spring always presses the outer and inner plates towards each other. When the difference between the speeds of the drive shafts is small, the selector valve closes the second passage and opens the third passage. When the difference is large, the valve opens the second passage and closes the third passage.