| 摘要 |
PURPOSE:To surely avoid unwilling acceleration in an automatic speed controller for an automobile, by equipping a driver circuit forming a power source circuit of servo valve and two-way valve with an individual switch means. CONSTITUTION:Under an automatic running control condition, in which self holding of a relay 11 switches contacts 11A, 11B to flow an electric current in a two-way valve 7 and servo amplifier 6 in case of occurrence of welding in either one of the contact 11A or 11B, a welding detector circuit 19 detects the welding by brake operation to keep holding output of a terminal C to positive voltage. This causes a transistor 20 to turn on while 15 to turn off simultaneously a transistor 18 to turn on through a diode 22 while 10 to turn off, and the relay 11 is urged to the reset direction, then the contact 11B is reset to return the two-way valve 7 to the atmospheric pressure feed side for welding of the contact 11A, while the contact 11A is reset to release self holding for welding of the contact 11B. Further short-circuit of the transistor 15, welding of a switch 3, etc. can similarly avoid unwilling acceleration. |
