PURPOSE: To perform the daily inspection of a variable relief valve by a rear wheel steering control device itself by feeding the maximum fluid pressure immediately after the start of an engine to perform the precheck steering of rear wheels, and judging the operating state of the variable relief valve on the basis of the actual steering angle and a steerable area corresponding to a steering wheel angle.
CONSTITUTION: In the precheck steering routine, when a rear wheel steering angle control valve 28 is changeover-operated to reach the maximum opening and even if oil pressure with the pressure value P1 is fed to a rear wheel power cylinder 6, rear wheels RW can be steered only up to 0.8°. The actual rear wheel steering angle is therefore put in a fixed area by a driving current I, but if the actual rear wheel steering angle is out of the fixed area when the driving current I is the maximum value IMAX, the generation of abnormality to a variable relief valve 48 can be judged. As a result, a controller 44 opens an unloader valve 42 and lights an alarm lamp 140. The rear wheel power cylinder 6 is put out of operation, and the rear wheels RW are kept in the rectilinear state.
| JP5151625 | Steering support device |
| JP2020164160 | AUTOMATIC TRAVEL FARM FIELD WORK VEHICLE |
TAKEO TAKESHI
TANAKA TADAO
