| 摘要 |
PROBLEM TO BE SOLVED: To provide a speed changing device of which the vehicle speed setting is easy, and the power transmitting efficiency is high, and which has less troubles due to an overrun of the machine body, or a rise in oil temperature during working. SOLUTION: In the power vehicle 1 with a toroidal-type transmission 8, a vehicle speed setting apparatus 7 for controlling the angle of a power roller 38 is provided. When the machine body receives a specified propelling force or higher for advancing the machine body while a ground working machine is lowered and brought into contact with the ground, the power vehicle 1 is switched to a 4-wheel driving state, and at the same time, the toroidal-type transmission 8 is switched to the vehicle speed reducing side. In addition, when the output of a horizontal control is generated to keep the ground working machine 85 being connected in a manner to be freely laterally rollable under a horizontal posture, the speed changing control to the toroidal-type transmission 8 is interrupted, and the speed changing control is made possible at the point when the horizontal output is stopped. When the oil temperature of a hydraulic oil flowing in/out to/from a hydraulic cylinder 40 for controlling the power roller 38 of the toroidal-type transmission 8 rises to a specified value or higher, the control output on the vehicle speed ascending side is temporarily stopped. COPYRIGHT: (C)2004,JPO&NCIPI |
