Komatsu Corporation

Hideki Kado

Sadao Nunotani

Seita Hayashi

Mitsuru Arai

Mitsuru Oshiro

Yuuichi Yamamoto

Koichi Morita

A forward/backward switching control apparatus for a hydraulic drive vehicle that includes the following structures. A variable displacement type hydraulic pump driven by an engine for discharging pressure oil in both directions. An electromagnetic pump inclination angle control mechanism making the discharge displacement of the variable displacement type hydraulic pump variable and for causing the same to discharge in both directions. An electric control outputting signals to run the hydraulic drive vehicle forward, backward and forward/backward. A control device outputting, when the electric control is switched forward/backward to output the forward/backward signal and when the time for switching the forward/backward signal is not longer than a preset time, a first modulate signal for delaying the return times from the forward position to the neutral position and from the backward position to the neutral position to the electromagnetic pump inclination angle control mechanism.

Forward/backward switching control apparatus for hydraulic drive vehicle, and control method therefor

Travel drive apparatus for hydraulic drive work vehicles and control therefor

A travel drive apparatus for a hydraulic drive work vehicle and control method therefor, the apparatus including: a travel hydraulic pump driven by the power of an engine; a hydraulic motor that receives discharged oil from the travel hydraulic pump and causes the vehicle to travel; a travel changeover valve that receives the discharged oil from the travel hydraulic pump, supplies the discharged oil to the hydraulic motor and discharges return oil from the hydraulic motor to a tank, in which the travel drive apparatus comprises; an accelerator for controlling an engine rotational speed; an operation unit for selecting vehicle forward travel, stop, and reverse travel; the travel changeover valve being adapted for receiving signals from the operation unit, switching the discharge oil supplied from the travel hydraulic pump to the hydraulic motor, and controlling vehicle forward travel, stop and reverse travel; a relief valve that regulates pressure for controlling the hydraulic motor when the vehicle has decelerated, positioned between the travel changeover valve and the hydraulic motor; and a pressurizing unit for raising the set pressure at the relief valve controlling the hydraulic motor when the engine rotational speed is increased, while switching the vehicle from forward travel to reverse travel, or from reverse travel to forward travel, so that the work vehicle may switch over from forward to reverse travel; or vice versa, while exhibiting good acceleration performance.

Travel drive apparatus for hydraulic drive work vehicle and control method therefor

Backpressure control circuit for hydraulic drive device

Counter balance valve

Hydraulic braking apparatus having two safety valves

Swash plate angle changing apparatus for a piston pump/motor of swash

Growing community of inventors

Oyama, Japan

Hideki Kado