Turning control system for a hydro-mechanical transmission

摘要

A turning control system for a hydro-mechanical transmission of a vehicle including a mechanical transmission having a plurality of speed range change-over clutches, a pair of output shafts connected to the mechanical transmission, and pairs of hydraulic pumps and motors, each motor being operatively connected to the mechanical transmission. A turning of the vehicle is effected by changing displacement volume of one of the hydraulic pumps relative to the other pump to thereby change number of revolutions of one output shaft relative to the other output shaft. The turning control system includes a plurality of fluid pressure detection switches for detecting one of speed range change-over clutches currently engaged, a pair of motor speed detectors for detecting hydraulic motor speeds, an engine speed detector for detecting engine speed and a steering angle detector for detecting steering angle. Signals from the above recited switches and detectors are fed into an arithmetic unit where current value of radius of turning is compared with optimum radius of turning corresponding to the current steering angle stored therein and a turning signal is generated therefrom. A pair of adders are provided for sending out signals to actuators of the hydraulic pumps. The signals from the adders are such ones which will gradually approximate the turning signal to zero whereby optimum radius of turning corresponding to vehicle speed can be obtained automatically.