Kawasaki Jukogyo Kabushiki Kaisha

Jun Umekawa

Akihiro Kondo

Hideyasu Muraoka

Yousuke Kataoka

A hydraulic pump performance deterioration detection system according to one embodiment includes: a variable displacement hydraulic pump that supplies a hydraulic liquid to a hydraulic actuator to move the hydraulic actuator; a regulator that changes a displacement of the hydraulic pump in accordance with a command current; and control circuitry that feeds the command current to the regulator. When the hydraulic actuator is not moving, in a state where a switching valve located on a passage through which the hydraulic liquid delivered from the hydraulic pump flows is switched to a closed position and the hydraulic pump is being driven at a predetermined rotation speed, the control circuitry determines whether or not performance of the hydraulic pump has deteriorated based on a current value of the command current and a delivery pressure of the hydraulic pump measured by a pressure sensor.

Hydraulic pump performance deterioration detection system

A hydraulic pump performance deterioration detection system according to one embodiment includes: a hydraulic pump that is driven by a prime mover and that supplies a hydraulic liquid to a hydraulic actuator to move the hydraulic actuator; a switching valve located on a passage through which the hydraulic liquid delivered from the hydraulic pump flows, the switching valve being switchable between an open position and a closed position; and control circuitry configured to change a rotation speed of the prime mover. When the hydraulic actuator is not moving, in a state where the switching valve is switched to the closed position, the control circuitry determines whether or not performance of the hydraulic pump has deteriorated based on the rotation speed of the prime mover and a delivery pressure of the hydraulic pump measured by a pressure sensor.

A hydraulic drive system includes a hydraulic pump, a boom-dedicated control valve, a turning-dedicated control valve, a boom-dedicated operation unit, a turning-dedicated operation unit, and a driving control unit. If an operating amount of the turning-dedicated operating portion where a concurrent operation is performed and a single operation is performed are the same, the driving control unit adjusts a turning driving command, that an opening area between the hydraulic pump and a turning motor where the concurrent operation is performed is less than the opening area between the hydraulic pump and the turning motor where the single operation is performed, the concurrent operation wherein the turning operation command is outputted from the turning-dedicated operation unit and a boom operation command is outputted from the boom-dedicated operation unit, the single operation wherein the turning operation command is outputted, but the boom operation command is not outputted from the boom-dedicated operation unit.

Hydraulic drive system

A hydraulic actuator; a control valve that controls supply and discharge of hydraulic oil to and from the hydraulic actuator; a pilot operation valve connected to the operation valve by a pair of pilot lines; a proportional solenoid pressure-reducing valve provided on at least one of the pair of pilot lines; an operation detector that outputs an operation amount signal in accordance with an inclination angle of an operating lever of the pilot operation valve; and a controller that controls the proportional solenoid pressure-reducing valve such that, from immediately after a change amount per unit time in the operation amount signal outputted from the operation detector has decreased by a threshold value or more, a pilot port pressure of the control valve gradually decreases to zero due to communication of a secondary pressure port and a tank port of the proportional solenoid pressure-reducing valve with each other.

Growing community of inventors

Akashi, Japan

Jun Umekawa