Hitachi Construction Machinery Co., Ltd.

Tsutomu Udagawa

Akira Nakayama

Masami Ochiai

Kazuo Takiguchi

Hidetoshi Satake

Tsukasa Toyooka

Shigeyuki Sakurai

Makoto Sugaya

Yukihito Suzuki

Kouji Ishikawa

Manabu Edamura

Hiroaki Tanaka

Eiji Egawa

Ryohei Yamashita

Yukihiko Sugiyama

Mitsuo Aihara

Junji Yamamoto

Teruo Igarashi

Toshimi Sakai

Kouji Funato

Kazuhisa Ishida

Shinya Imura

Shiho Izumi

Yasutaka Tsuruga

Kazunori Nakamura

Hidekazu Moriki

Tsuyoshi Nakamura

Kazuo Fujishima

Hidenobu Tsukada

Takashi Yagyu

Kensuke Sato

Takenori Hiroki

Mitsuo Sonoda

Manabu Sugiura

Yuichi Kunitomo

Koji Ishikawa

Katsumi Ueno

Takashi Yagyuu

Kensuke Satou

Atsushi Kanda

Hideo Sorata

Shinobu Higashi

A cost required to perform the diagnosis of the degradation such as a reduction in output power of an engine while engine degradation diagnosis accuracy is improved. To this end, a controller(engine diagnosing device) determines whether a hydraulic pumpis in a preset loaded state (an operation scene where a load torque of the hydraulic pumpis in a stable state) for acquiring diagnosis data of an engine, and validates a controlled variable related to a torque command value Ta of speed sensing control as the diagnosis data of the enginewhen it is determined that the hydraulic pumpis in the present loaded state, generates time history data using this validated controlled variable as a current feature variable, and enables this time history data to be displayed as trend data for engine diagnosis on a display device

Construction machine

There is provided a construction machine that is capable of measuring a minute leakage flow rate of a one-sided tilting variable displacement hydraulic pump. The construction machine includes a pressure sensor that detects a pressure of a hydraulic pump, a bleed-off adjusting device that is enabled to adjust a bleed-off flow rate of the hydraulic pump, and an input device that gives an instruction for measurement of a leakage flow rate of the hydraulic pump. The controller is configured to measure, when the controller determines that the operation device is in a non-operated state and when a measuring command is inputted from the input device, a pressure of the hydraulic pump while changing a control command value for the bleed-off adjusting device in a state in which a flow rate of the hydraulic pump is maintained, and calculate the leakage flow rate of the hydraulic pump on the basis of the control command value for the bleed-off adjusting device at the time that the pressure of the hydraulic pump is stabilized at a predetermined pressure.

A hydraulic work machine is provided in which left and right hydraulic motors are driven independently of each other by two hydraulic pumps and in which an anomaly of any of the left and right track devices can be detected with high accuracy. The hydraulic work machine includes a first pressure sensorconfigured to detect a first pump pressure that is a delivery pressure of a first hydraulic pumpand a second pressure sensorconfigured to detect a second pump pressure that is a delivery pressure of a second hydraulic pump. When a controllerdecides, from detection results of a travel operation detectorand work operation detectorsand, that a work implementis not operated but travel operation devicesandare operated and besides left and right track devicesandare straightly traveling, the controllercalculates an anomaly decision evaluation value based on a pressure difference value obtained by subtracting one from the other of the first pump pressure and the second pump pressure and decides, based on a result of comparison between the anomaly decision evaluation value and a predetermined decision reference value, that one of the left and right track devices has an anomaly.

Hydraulic work machine

To provide a hydraulic control system for a working machine with high fuel efficiency and higher versatility to be capable of being adapted to special work. The hydraulic control system for the working machine according to the present invention includes: a plurality of directional control valves (, . . . ), more than one of which is connected in parallel to each of a plurality of hydraulic pumps () to supply hydraulic oil from the hydraulic pump to each of the corresponding actuators (); operating devices () to which an operator inputs manipulated variables; a connection map () storing a precedence order for connection between a plurality of hydraulic pumps and a plurality of directional control valves; and a controller () controlling the connection conditions of the pumps and the actuators on the basis of the connection a&#xa5;map and operation signals.

Hydraulic control system for working machine

A work machine including a specific actuator that supplies hydraulic fluid from a plurality of hydraulic pumps includes: first and second hydraulic pumps communicating with a first hydraulic actuator; a first control valve returning hydraulic fluid delivered by the first hydraulic pump to a tank; and a load detection section that detects a load on the first hydraulic actuator. A control valve drive section drives the first control valve such that a communication area between the first hydraulic pump and the tank is enlarged corresponding to an increase in the load on the first hydraulic actuator; and a flow rate control section, during supply of the hydraulic fluid from the first and second hydraulic pumps to the first hydraulic actuator, controls to reduce a delivery flow rate of the first hydraulic pump corresponding to an increase in the load on the first hydraulic actuator.

Hydraulic control system for work machine

The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controllerincludes a target pump pressure setting unitwhich calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detectorA/B based on the operation amount signal and a pump flow rate upper limit setting unitwhich calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal. The tilt amount of the hydraulic pumpis controlled based on the target pump delivery pressure calculated by the target pump pressure setting unit, the pump flow rate upper limit calculated by the pump flow rate upper limit setting unit, and the delivery pressure of the hydraulic pumpdetected by a pressure detector

Hydraulic control device for work machine

In a hydraulic closed circuit system with hydraulic pumps which maintains a well-balanced flow rate by automatically controlling the flow rate, a first hydraulic pump is connected to a hydraulic cylinder device such that the hydraulic closed circuit is made, a second hydraulic pump is connected at one of paired delivery ports to a bottom side of the hydraulic cylinder device and at the other of the ports to a tank, and a prime mover drives the first and second hydraulic pumps and recovers motive power from these pumps. A pump capacity control unit detects a moving direction of the hydraulic cylinder device, and a pressure in a lower-thrust side of the device, and controls a capacity of the second hydraulic pump so that the flow rate during the extension/retraction of the hydraulic cylinder device becomes balanced between the first and second hydraulic pumps and the hydraulic cylinder device.

Hydraulic closed circuit system

There is provided a hydraulic excavator including a hydraulic pump () driven by an engine (), a boom cylinder () driven by hydraulic fluid delivered from the hydraulic pump (), a swing motor () driven electrically, an operating device (A) for operating the boom cylinder (), an operating device (B) for operating the swing motor (), and a vehicle body controller () which limits the power of the swing motor () in accordance with the operation amount of the operating device (A) when the two operating devices (A,B) are operated in combination. The power limit value of the swing motor () varies depending on the output of the engine (). This allows a good operational feeling to be retained in combined operation regardless of the operating state of the engine.

Work machine

To automatically prevent a reverse movement by inhibiting an excessive increase in an output torque of an electric motor. A means () calculates a target value for a rotation speed based on a command from a system (), a means () calculates a deviation between a detection value from a rotation speed sensor () and the target value, a means () calculates a first target torque in a direction that the deviation will be eliminated, and a means () calculates, based on a command from the system (), a second target torque in the same direction as the target value. A means () calculates a variation in a rotation angle of an electric motor () in a first range, and a means () calculates the same variation in a second range. A means () calculates, based on the variations from the means (), a third target torque in a direction that the rotation angle will return to a rotation angle before a predetermined time (t), and a means () limits the first target torque to one of the second and third target torques, said one target torque being in the same direction as the first target torque and being greater in absolute value. Substantially an entirety of the first range specifies a range for the variation in one direction, a remaining small range specifies a range for the variation in the other direction, substantially an entirety of the second range specifies a range for the variation in the other direction, and a remaining small range specifies a range for the variation in the one direction.

Rotation control device of working machine

A working machine swing control system is provided with an actual rotation speed sensor and a controller. The actual rotation speed sensor senses an actual rotation speed of a swing motor. The controller controls a drive torque of a drive unit, which drives the swing motor, such that a difference between a target rotation speed outputted from a swing control device and the actual rotation speed outputted from the actual rotation speed sensor is reduced to zero. The swing control system includes a correction device for correcting the target rotation speed outputted from the swing control device according to a work posture of working equipment and a work load on the working equipment.

Rotation control device for working machine

A travel control device for a work vehicle includes: a hydraulic pump; a plurality of hydraulic motors connected to the hydraulic pump in parallel through a closed-circuit connection, that drive different wheels with pressure oil delivered from the hydraulic pump; a slip detection device that detects a slip occurring at each of the wheels; and a flow control device that reduces, upon detection of a slip occurring at any of the wheels by the slip detection device, a quantity of pressure oil supplied to a hydraulic motor for driving the wheel at which the slip has been detected, among the plurality of hydraulic motors.

Travel control device for work vehicle and work vehicle

A travel drive system for a work vehicle includes: an HST drive device comprising a hydraulic pump driven by a prime mover and a hydraulic motor connected to the hydraulic pump by a closed circuit; an electric motor driven by using electric power generated by drive of the prime mover; a first drive wheel driven by the HST drive device; a second drive wheel driven by the electric motor; a vehicle speed detector that detects a vehicle speed; and a control unit that distributes output of the prime mover to the HST drive device and to the electric motor such that, as the vehicle speed detected by the vehicle speed detector increases, a proportion of a first power distributed to the HST drive device decreases and a proportion of a second power distributed to the electric motor increases.

Travel drive system for work vehicle, work vehicle, and travel drive method

A hydro-static transmission travel system for a working machine enables the working machine to travel over a range from low speed to high speed with a simplified circuit arrangement. By referring to a machine traveling speed (vehicle speed) based on a detected signal from a rotation sensor, a controller computes respective target tilting amounts of hydraulic motorsand controls the tilting amount for the hydraulic motors and a clutch. Depending on whether the traveling speed exceeds a setting speed as a reference boundary, the controller selectively switches over a drive mode between low-speed four-wheel drive, in which travel unitsare both driven, and high-speed two-wheel drive, in which the front-wheel side hydraulic motoris controlled to zero displacement and only the rear-wheel side travel unitis driven.

HST travel system for working machine

A hydraulic drive system comprises directional flow control valves (-) for selectively supplying a hydraulic fluid from a first hydraulic pump (), inflow control valves (-) disposed respectively in branch lines (A-C) branched from a supply line () for supplying a hydraulic fluid delivered from a second hydraulic pump () to rod pushing-side chambers (A,A,A,A) of hydraulic cylinders, a bypass flow control valve () disposed in a line () connecting the supply line () and a reservoir (), and a controller () for computing control variables corresponding to operation command signals from control levers () and controlling the inflow control valves (-) and the bypass flow control valve () in accordance with the computed control variables. Thus, the number of flow control valves and the length of piping required for their connection can be reduced, and a total pressure loss can be further reduced.

Hydraulic driving system of construction machinery

The control valve apparatus holds a seat valve member in a position seated on a valve seat to thereby prevent a backward flow even if the pressure in the inlet chamber side becomes lower than the pressure in the outlet chamber side. With a pilot control valve member is in a closed state, when the pressure in the inlet chamber is higher, a pressurized medium is introduced to the control pressure chamber via a first valve unit and is cut off from the outlet chamber by a second valve unit. When the pressure in the outlet chamber is higher, the pressurized medium is introduced to the control pressure chamber via the second valve unit and is cut off from the outlet chamber by the first valve unit.

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Tsukuba, Japan

Tsutomu Udagawa