Method of hydraulically controlling speed change in automatic transmission for vehicle

Abstract

Abstract PURPOSE:To prevent the occurrence of speed change shock by controlling the supply of oil pressure to a frictional engaging element for selecting a rotary element so that the change ratio of rotational speed in the rotary element during the speed change in a transmission follows up a desired value. CONSTITUTION:A speed change gear 22 is constituted from a labyniyo type planet gear mechanism 36 in which a front sun gear 44 is connected to an input shaft 20 through a kick-down drum 52 and a front clutch 24. Oil pressure is supplied to a kick-down servo piston 30 such that the change ratio in rotational speed of the kick-down drum during speed change follows up that in a desired rotational speed. Thus, satisfactory speed change is achieved without excessive speed change shock and slip of a frictional engaging element.

Inventors

• 👤 Takeo Hiramatsu
• 👤 平松　健男
• 👤 Yuuichi Tanaka
• 👤 田中　祐市

Bibliographic Details