| 主权项 |
1. A speed change control system having a constant speed mode for causing a vehicle to travel at a constant speed, comprising:
a stepless speed change device for steplessly speed-changing a rotational power from an engine and outputting the speed-changed power; a speed change control section for setting a speed change value of the stepless speed change device; a speed change operational tool for providing the speed change control section with a speed change command; a constant speed travel operational device for providing the speed change control section with a changing command for changing a constant speed mode speed change value which is a speed change value at the time of the constant speed mode, a shifting command for shifting to the constant speed mode, and a departing command for departing from the constant speed mode; a storage section for storing the constant speed mode speed change value set by the constant speed travel operational device; and a constant speed travel management section for causing the speed change control section to execute the constant speed mode with using the constant speed mode speed change value retrieved from the storage section, based on the shifting command from the constant speed travel operational device, wherein the constant speed travel operational device is constituted of a single constant speed travel operational instrument, and the constant speed travel operational instrument has a changing operational position for providing the speed change control section with the changing command by a predetermined speed change value unit, a shifting operational position for providing the speed change control section with the shifting command, and a departing operational position for providing the speed change control section with the departing command, and wherein the constant speed travel operational instrument is capable of operational displacements in one direction and in the other direction, across and relative to a neutral position as a reference point to which the instrument is urgedly maintained, a terminal end operational displacement position in the one direction is the shifting operational position, a terminal end operational displacement position in the other direction is the departing operational position, and a unit operational displacement position to the terminal operational displacement positions in the one direction and the other direction is the changing operational position. |
