Patent ID: 8147376
Filing Date: 2012-04-03
Classification: F16H,Y10T

Abstract:
1. A construction vehicle comprising: an input shaft to which rotation from an engine is inputted; a first speed-change shaft and a second speed-change shaft to which rotation from the input shaft is inputted; an output shaft to which rotation from the first speed-change shaft and the second speed-change shaft is inputted; a clutch mechanism configured and arranged to switch between a transmitting state and a non-transmitting state of rotation from the input shaft to the first speed-change shaft, and to switch between a transmitting state and a non-transmitting state of rotation from the input shaft to the second speed-change shaft; a first transmission mechanism configured and arranged to shift rotational speed of the first speed-change shaft between a plurality of speeds that belongs to a first group of speeds, and to transmit the rotation to the output shaft, the first transmission mechanism having a plurality of speed-change gears that corresponds to the plurality of speeds belonging to the first group; a second transmission mechanism configured and arranged to shift rotational speed of the second speed-change shaft between a plurality of speeds that belongs to a second group of speeds, and to transmit the rotation to the output shaft, the second transmission mechanism having a plurality of speed-change gears that corresponds to the plurality of speeds belonging to the second group; a first coupling mechanism configured and arranged to switch between a coupling state and a non-coupling state between the first speed-change shaft and a selected one of the speed-change gears of the first transmission mechanism by selectively engaging with a clutch gear provided to the selected one of the speed-change gears of the first transmission mechanism; a second coupling mechanism configured and arranged to switch between a coupling state and a non-coupling state between the second speed-change shaft and a selected one of the speed-change gears of the second transmission mechanism by selectively engaging with a clutch gear provided to the selected one of the speed-change gears of the second transmission mechanism; a vehicle speed detecting section configured and arranged to detect a vehicle speed; and a control unit configured to control the clutch mechanism, the first and second transmission mechanisms, and the first and second coupling mechanisms to shift gears from a current speed of one of the first and second groups to a target speed of the other of the first and second groups by performing a pre-shifting control to couple a target speed-change gear corresponding to the target speed with a target speed-change shaft, which is one of the first and second speed-change shafts in the non-transmitting state of rotation from the input shaft, in a state in which coupling is established between a current speed-change gear corresponding to the current speed and a current speed-change shaft, which is the other of the first and second speed-change shafts in the transmitting state of rotation from the input shaft, and then disabling transmission of rotation between the current speed-change shaft and the input shaft and enabling transmission of rotation between the target speed-change shaft and the input shaft, the control unit being configured to perform pre-shift auxiliary control prior to the pre-shifting control to input the rotation of the input shaft to the target speed-change shaft in a state in which the target speed-change shaft is not coupled to the plurality of speed-change gears, when the vehicle speed detected by the vehicle speed detector is zero.