Hitachi Construction Machinery Co., Ltd.

Gen Yasuda

Toichi Hirata

Hiroshi Watanabe

Yukio Aoyagi

Kenji Kakizawa

Genroku Sugiyama

Yasuo Tanaka

Kazunori Nakamura

Koji Fujita

Yusuke Kajita

Eiki Izumi

Yoichi Kowatari

Masami Ochiai

Yusaku Nozawa

Takenori Hiroki

Yasushi Arai

Hiroshi Onoue

Sotaro Tanaka

Shigetaka Nakamura

Hironori Itou

Yoshinori Ohwada

Hisashi Tago

Hideyo Kato

Ryou Takaichi

Akihide Yamazaki

Takayuki Yamakawa

Kazuyoshi Narita

Kazuhiko Otsubo

Tomohiko Yasudi

Saimon Otaka

A reduction in measurement accuracy of a concentration sensor is minimized. An exhaust gas purifying device of a work machine includes a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage. The exhaust gas purifying device of a work machine includes: a storage unit that stores the reducing agent; a concentration sensor that has a sensing part placed within the storage unit to detect a concentration of the reducing agent; an air-bubble removal device that injects the reducing agent toward the sensing part; and a reducing agent pump that supplies the reducing agent in the storage unit to the air-bubble removal device.

Exhaust gas purifying device of work machine

A pump control apparatus for a hydraulic work machine includes: a rotation speed setting device that sets a target rotation speed for an engine; a rotation speed control device that controls an engine rotation speed so as to adjust the engine rotation speed to the target rotation speed; a first variable hydraulic pump used to drive a work hydraulic actuator, driven by the engine; a second variable hydraulic pump used to drive a cooling fan, driven by the engine; and a pump control device that controls an output flow rate of the first variable hydraulic pump and an output flow rate of the second variable hydraulic pump so as to ensure that a sum of an intake torque of the first variable hydraulic pump and an intake torque of the second variable hydraulic pump does not exceed an engine output torque determined in advance based upon the target rotation speed. The pump control device a) controls the output flow rate of the second variable hydraulic pump based upon the target rotation speed and a target output flow rate of the second variable hydraulic pump assuring a required cooling air volume at the cooling fan; and b) regulates the intake torque of the first variable hydraulic pump by calculating the intake torque of the second variable hydraulic pump and subtracting the intake torque of the second variable hydraulic pump from the engine output torque determined in advance based upon the target rotation speed.

Pump control apparatus for hydraulic work machine, pump control method and construction machine

To permit a precise and easy adjustment of a pump absorption torque of a main pump in accordance with environmental conditions when a sub-pump different in characteristics from the main pump is connected to a prime mover. A main controllerincludes a processor means for setting the level of an absorption torque of a cooling fan pumpat a maximum absorption torque in use, a processor means for incrementing an adjustment target absorption torque for a main pumpat a slow rate from a sufficiently small pump absorption torque, and a processor means for repeating loading of a load factor signal and the increment of the adjustment target absorption torque as long as 'NO' is determined by a fourth determination means, and a processor means for storing the adjustment target absorption torque as an adjustment value when 'YES' has been determined by the fourth determination means.

Pump torque controller of hydraulic working machine

The present invention includes: a displacement altering unit for generating a displacement control pressure corresponding to a displacement control signal; an input unit for inputting a target displacement; a pressure calculating unit for calculating a displacement control pressure corresponding to the target displacement based upon predetermined reference characteristics of the displacement altering unit; a pressure detecting unit for detecting a pressure corresponding to the displacement control pressure; a signal calculating unit for calculating a displacement control signal corresponding to the input target displacement; and a correcting unit for correcting the displacement control signal calculated by the signal calculating unit based upon the displacement control pressure having been calculated by the pressure calculating unit and the measured pressure detected by the pressure detecting unit.

Displacement control signal correction method, displacement control device, construction machine and displacement control signal correction program

A machine body controllerA includes a modification control unitAb for computing a torque modification value based on detected signals from environment sensorstoand modifies a maximum absorption torque of a hydraulic pump controlled by a basic control unitAa. An engine controllerB includes a modification control unitBb for computing an injection modification value based on detected the signals from the environment sensorstoand modifies a fuel injection state of a fuel injection devicecontrolled by a basic control unitBa. The controllersA,B further include computation element altering unitsA communication controllerC downloads alteration data obtained from an external terminalto the computation element altering unitswhereby corresponding computation elements contained in the modification control unitsAb,Bb are altered. As a result, it is possible in any environments to approprately modify the maximum absorption torque of the hydraulic pump and the fuel injection state of the injection device, and to sufficiently develop the performance of a construction machine.

Signal processing system for construction machine

A hydraulic drive system for a supersized hydraulic working machine such as a hydraulic excavator includes hydraulic pumps connected to main lines through a delivery line and a supply line. Branch portions from the main line include flow control valves for allowing a hydraulic fluid to flow from the hydraulic pumps toward hydraulic cylinders. A hydraulic reservoir is connected to the main lines through a reservoir line and a drain line. Other branch portions for the drain line include flow control valves for allowing a hydraulic fluid to flow from the hydraulic cylinders toward the hydraulic reservoir. A line branched for the delivery line includes a bypass valve for supplying the hydraulic fluid delivered from the hydraulic pumps to the supply line at a desired flow rate and returning the remaining hydraulic fluid to the hydraulic reservoir.

Hydraulique drive device

A pump failure alarm system which is provided in a hydraulic working machine comprising hydraulic pumps driven by a prime mover, delivery lines joining with one another into one common delivery line on the downstream side, check valves provided in the delivery lines upstream of a point where the delivery lines join with one another, a hydraulic cylinder driven by a hydraulic fluid introduced through the common delivery line, and a hydraulic reservoir. The pump failure alarm system comprises pressure sensors for detecting respective delivery pressures of the hydraulic pumps, bypass lines having one ends connected to the delivery lines at points upstream of the check valves and the other ends connected to the hydraulic reservoir, solenoid switching valves for opening and closing the associated bypass lines, an alarm display unit for giving an alarm in correspondence to each of the hydraulic pumps, and a controller.

Pump failure alarm system for hydraulic working machine

Hydraulic drive system for construction machine

Hydraulic drive system with pressure compensating valve

Hydraulic drive system for construction machines

Growing community of inventors

Tsuchiura, Japan

Gen Yasuda