| 摘要 |
<p>Load increase rate computation portion (21) computes a increase rate (²) of a load acting on a work vehicle 1 (Step S102). The transmission control portion (22) shifts a high-speed gear (second speed) down to a low-speed gear (first speed) with producing a lock-up state that a lock-up clutch (4a) is engaged when the load increase rate (²) is less than a load increase rate threshold (²c) in shifting the high-speed gear (second speed) down to the low-speed gear (first speed) (Steps S103, S105). Additionally, the transmission control portion (22) shifts the high-speed gear (second speed) down to the low-speed gear (first speed) with producing a torqcon state that the lock-up clutch (4a) is disengaged when the load increase rate (²) is equal to or greater than the load increase rate threshold (²c) in shifting the high-speed gear (second speed) down to the low-speed gear (first speed) (Steps S103, S104).</p> |
