FAIL-SAFE CONTROL DEVICE FOR CONTINUOUS VARIABLE TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To restrain an excessive increase in oil temp. caused by increase in an excessive line pressure during running operation of a vehicle by detecting failure of line pressure control means according to a line pressure command value of shift control means as well as the detection value of line pressure. SOLUTION: A shift controller of a continuously variable transmission 100 is provided with shift control means calculating a line pressure command value according to the operational condition of a vehicle, and according to the line pressure value line pressure control means 103 controls oil pressure from a hydraulic source and supplies the controlled pressure to a variable pulley. Fail- safe means 104 is also provided, and the means 104 supplies maximum oil pressure to the variable pulley when failure in the means 103 is detected. The failure thereof 103 is determined by failure determination means 106 according to the line pressure value detected by line pressure detection means 105 and the line pressure command value. At the time of failure the engine speed is reduced by engine control means.