| 摘要 |
PURPOSE:To make a steering function maintainable to perfection even when anything unusual happens, by comparing the controlled flow of a solenoid valve's opening controlling hydraulic fluid flow with the desired controlled flow and, when its difference goes beyond the specified value of flow, discriminating it as trouble whereby operating a sub-control circuit. CONSTITUTION:When an ignition switch 28 is closed, opening in a solenoid valve 30 is throttled in proportion to an increase in a car speed to be detected at a car speed detection device 33 by a control circuit 32 and thereby a feed quantity to a power steering mechanism 4 is decreased. At this time, the output of a pulse/voltage conversion circuit 101 to be set according to the car speed is compared with the output of detection resistance 107 detecting an electric current of the solenoid valve 30 by a discriminator circuit 112, and when trouble is discriminated there, a transistor 106 is turned to OFF and a main control circuit 110 is cut off, while an alarm lamp 108 is lighted. On the other hand, a transistor 105 is turned to ON and the current regulated by a resistor 104 of a sub-control circuit 111 is fed to the solenoid valve 30. |
