| 摘要 |
PURPOSE:To reduce a feeling of physical disorder at the time of switching and allow a safe operation even in the case where a worker forgets the last steering mode by providing a control unit for giving a priority to front wheel steering mode at the time of artificially switching control mode from automatic steering mode to manual steering mode. CONSTITUTION:The front wheels and rear wheels of an agricultural tractor are formed in such a manner as to be capable of being steered independently or interlockingly, and front wheel steering mode, rear wheel steering mode and front and rear wheel reversed phase steering mode can be switched by the combination of ON and OFF of respective solenoids 53, 38 of electromagnetic valves of front and rear wheel steering systems. Namely, in automatic steering mode, the steering mode is transferred to the front and rear wheel reversed phase steering mode when a working machine rise detecting sensor 84 detects the rise of a working machine and to the rear wheel steering mode when the reverse is detected by a reverse detecting sensor 85. In manual steering mode, the steering mode set by a worker is executed, but just after the control mode is switched to the manual steering mode by an automatic-manual change-over switch 83, the steering mode is trolled by a control part 74 in such a manner that a priority is given to the front wheel steering mode. |
