JPS6430951A - Planetary gear type automatic continuously variable transmission - Google Patents

Abstract

PURPOSE:To control a transmission to automatically correspond to a running condition by transmitting output torque from a prime mover to an output shaft through the first and second planetary gear mechanisms while detecting the output torque by a torque sensor and variably controlling the resistance of a ring gear. CONSTITUTION:Rotary driving power of an engine 1 is transmitted to an output shaft 7 via the first planetary gear train 2, having a movable ring gear 9, and the second planetary gear train 3, having a fixed ring gear 13, from an input shaft 6. While detecting output torque to the input shaft 6 by a torque sensor 18, an actuator 24 is driven through a control circuit 5 and a control mechanism 4 in accordance with a level of the detected output torque, and the speed of an oil hydraulic pump 20 is controlled by opening and closing an oil valve 19. By the constitution thus described, also a speed of the ring gear 9 is controlled through a worm wheel 15, that is, the ring gear 9 stops standing still, when the valve 19 is completely closed, and integrally rotates with a carrier 8 by the action of a one-way clutch 11, when the valve 19 is fully opened, and a speed change of 1:1/5 can be attained. In this way, optimum torque- rotary speed is automatically obtained in accordance with a running condition.