AUTOMATIC GEAR SHIFT CONTROL DEVICE FOR VEHICLE

摘要

PURPOSE:To perform back up during failure of a car speed sensor without arranging a car speed sensor by performing switch control of the engaging state of an automatic transmission mechanism, based on an estimated car speed calculated from the engine speed and output torque. CONSTITUTION:An automatic transmission 70 provided with a torque converter 72 and an auxiliary transmission mechanism 74 is coupled to an engine 2. A valve body 76 having the automatic transmission 70 is provided at its interior with a first solenoid 78 being a gear speed varying means to switch the engaging state of the gear speed of the auxiliary transmission mechanism 74 and a second solenoid valve 80. An oil temperature sensor to detect an oil temperature in the automatic transmission 70 by the valve body 76 is positioned and a car speed sensor 84 operated through rotation of a rotary shaft is arranged in the automatic transmission 70. Thus, the auxiliary transmission mechanism 74 of the automatic transmission 70 is controlled by switching a shift position to the engaging state of a highest gear shift speed. This constitution prevents lowering of operation performance even in failure of the car speed sensor and reduces limit on a gear shift.