JPS6435151A - Safety device for transmission - Google Patents

Abstract

PURPOSE:To prevent occurrence of serious accident by using another circuit separate from speed change control circuit, installing a circuit which provides forced response of electric command and clutch double engagement sensing to the neutral, and thereby taking effective measure to electrical or mechanical troubles. CONSTITUTION:Six speed change clutches H, L, 1, 2, 3, R are oil-hydraulically controlled by pressure control valves 21-26 independently from one another, and an auto speed change controller 40 to control them by electric commands calculates signals from a shift level 41, engine number of revolutions, throttling amount sensors 32, 36, etc., and the calculations are given out. Separately from this automatic speed change circuit an abnormality sensing circuit 60 senses eventual double engagement of clutch on the basis of the outputs from pressure sensors 51-56 for clutch pressures, and if the case is such, a relay 90 shuts off power supply to the controller 40 from a battery 80. This constitutes an effective measure for electrical and mechanical troubles, and serious accident can be prevented certainly.