Komatsu Corporation

Michihiro Aida

Masaki Shiohara

Tetsuya Morimoto

Kazuhito Nishimaki

Osamu Kodama

Nobuhito Yasuta

Taku Matsuo

Takafumi Takenaka

Tomonao Nagamura

Noritoshi Takekuma

A multi-speed transmission includes: an input member; an output member; first to fourth planetary gear sets arranged in order in an axial direction from the input member toward the output member and each including a sun gear, a planetary carrier and a ring gear; first to third clutches; and first to third brakes. Each of the first to third clutches and the first to third brakes is operatively coupled to at least one planetary gear set of the planetary gear sets, and selectively engageable to produce a set of different gear ratios including at least ten forward gear ratios and at least two reverse gear ratios between the input member and the output member. The first clutch selectively couples the third sun gear of the third planetary gear set to the fourth planetary carrier of the fourth planetary gear set.

Multi-speed transmission

A motor grader is provided with an engine, front and rear travel wheels, a transmission, a work implement, a control unit, and a vehicle speed adjusting knob. The transmission has hydraulic clutches for switching between forward and reverse travel and for switching between speed stages. The transmission changes the speed of power from the engine, and transmits the power to either the front travel wheels and/or to the rear travel wheels. The work implement includes a blade for grading. During travel at a forward first speed, the control unit causes one of the hydraulic clutches of the transmission to operate as a braking clutch such that the motor grader travels at a very low speed. The vehicle speed adjusting knob is a member for setting the vehicle speed during very low-speed travel to an arbitrary speed.

Motor grader

A motor grader includes an engine, a torque converter, a drive wheel, an engine revolution detector, and a control unit. The torque converter, including a lock-up clutch, transmits driving force from the engine. The drive wheel is rotationally driven by the driving force from the engine. The engine revolution detector detects engine revolution. When the lock-up clutch is engaged, the control unit is configured to: maintain the engaged state of the lock-up clutch when the engine revolution is greater than a predetermined lock-up release revolution lower than a low idle revolution; and switch the lock-up clutch into a disengaged state when the engine revolution is less than or equal to the predetermined lock-up release revolution.

In a motor grader, when a cylinder hydraulic pressure detected by a cylinder-hydraulic-pressure-detecting section is less than a predetermined threshold value, a control section makes a determination that the motor grader is in a running state and uses a running-hydraulic-pressure waveform corresponding to the running state to control the hydraulic pressure supplied to a clutch. When the cylinder hydraulic pressure is greater than or equal to the threshold value, the control section makes a determination that the motor grader is in a working state and uses a working-hydraulic-pressure waveform corresponding to the working state to control the hydraulic pressure supplied to the clutch.

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Komatsu, Japan

Michihiro Aida