Hitachi Construction Machinery Co., Ltd.

Masami Higaki

Tetsuji Tanaka

Eiichi Sakai

Hidenobu Tsukada

Hideo Nakayama

Hirofumi Ouchi

An automatic transmission device for a wheel loader includes: a shift mechanism; a work detection device that detects that the wheel loader is performing an excavation work; and a shift control device that executes control so as to downshift a speed stage at the shift mechanism if the work detection device detects that the wheel loader is performing the excavation work.

Automatic transmission device for wheel loader and wheel loader

A clutch control device includes: a plurality of hydraulic clutches built into a transmission; a clutch switching pattern storage device in which a plurality of clutch switching patterns, each defining engage/release changeover timing with which the plurality of hydraulic clutches are engaged/released are stored in correspondence to individual speed change patterns adopted by the transmission; a clutch switching pattern selection device that selects a clutch switching pattern stored in the clutch switching pattern storage device in correspondence to a speed change pattern for the transmission at a time of speed change; and a hydraulic control device that executes hydraulic control for the plurality of hydraulic clutches in correspondence to the clutch switching pattern selected by the clutch switching pattern selection device.

Clutch control device and clutch control method

A shift control device for a work vehicle that has a stepped automatic transmission includes: a control device that controls an engine rotation rate at the work vehicle and the stepped automatic transmission; a forward/reverse switchover member that outputs a forward/reverse switchover command for the work vehicle; and an operation quantity detection device that detects an accelerator pedal operation quantity in the work vehicle is operated. As the forward/reverse switchover command is output via the forward/reverse switchover member, the control device executes forward/reverse switchover control for the stepped automatic transmission and also controls the engine rotation rate so as to decrease the engine rotation rate gradually to a target lower limit value selected to ensure that a reverse rotation of a turbine runner at a torque converter in the work vehicle does not occur.

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Ryugasaki, Japan

Masami Higaki