Hitachi Construction Machinery Co., Ltd.

Kensuke Sato

Tsuyoshi Nakamura

Hiroyuki Azuma

Yasuo Okano

Kouji Ishikawa

Mitsuhiko Kanehama

Naoki Hagiwara

Takahiro Kobayashi

Hidenobu Tsukada

Kazunori Nakamura

Yusuke Kajita

Tsukasa Toyooka

Shohei Kamiya

Tsutomu Udagawa

Kazuhiro Shibamori

Eiji Egawa

Makoto Sugaya

Akira Nakayama

Kazuo Takiguchi

Masanori Ezawa

The purpose of the present invention is to provide a cooling fan control device for a construction machine, whereby the effects of heat caused by warm-up operation can be suppressed. This cooling fan control device is equipped with a control unit () that controls the rotational speed of a cooling fan () in accordance with a main pump discharge pressure (P) detected by a main pump discharge pressure sensor (), an engine cooling water temperature (Tw) detected by an engine cooling water temperature sensor (), a hydraulic oil temperature (To) detected by a hydraulic oil temperature sensor (), and an engine rotational speed (E) detected by an engine rotational speed sensor (). The cooling fan () is rotated at the rotational speed controlled by the control unit (), thereby sending the generated cooling air to an oil cooler () and a control valve ().

Cooling fan control device for construction machine

During boom-midair lowering operation in which a front work implementcan be turned under the self-weight of a boom, a hydraulic pump/motoris operated as a motor to operate a generator/electric motoras a generator. Power generation operation is performed by the hydraulic fluid discharged from a bottom-side chamberof a boom cylinderto recover positional energy. During jack-up in which the front work implementcannot be turned under the self-weight of the boom, the generator/electric motoris operated as an electric motor to operate the hydraulic pump/motoras a pump. The jack-up is performed by supplying the hydraulic fluid from the bottom-side chamberto rod-side chamberof the boom cylinderwithout supplying the hydraulic fluid from the main pumpto the rod-side chamberof the boom cylinder

Hydraulic drive system for construction machine

A relief pressure control system is provided with a controller for outputting, responsive to an adjustment signal output from a dial switch, a control signal to control a relief pressure of a variable solenoid relief valve, a display unit for displaying, responsive to display signals outputted from the controller, a relationship between a circuit pressure output from a pressure sensor and a pressure required by a hydraulic cylinder, and a control device constituting a start instruction unit for instructing a start of control of the variable solenoid relief valve. Stop valves are arranged in sections of main lines, which communicate a directional control valve and the hydraulic cylinder with each other, to open or close the section. The sections are located between positions on the main lines, where the variable solenoid relief valves are connected to the main lines, respectively, and the hydraulic cylinder.

Relief pressure control device for hydraulic work machine

A hydraulic drive device for a hydraulic excavator, includes: a first hydraulic pump; a first boom directional control valve and a second arm directional control valve which are connected in parallel to the first pump; a second hydraulic pump; and a second boom directional control valve and a first arm directional control valve which are connected in parallel to the second pump; wherein: the hydraulic drive device also includes: a third hydraulic pump; a third boom directional control valve connected to the third pump and controlling the flow of pressure oil supplied to a boom cylinder; and a third arm directional control valve connected in tandem with the third boom directional control valve and controlling the flow of pressure oil supplied to an arm cylinder.

Hydraulic drive device for working machine

To provide a construct ion machine in which the temperature of a battery and aqueous urea within an aqueous urea tank can be prevented from rising and high stability can be secured in the vehicle body. A small turning type hydraulic excavator () including: a counterweight () disposed at the rear of a turning upperstructure () provided with a front work machine () in the front thereof; an engine () disposed within an engine room () in front of the counterweight (); a heat exchanger () exchanging heat with the engine (); a fan () introducing outside air from an intake port () formed in the exterior of the engine room () into the engine room () to cool the heat exchanger (); a tail pipe () disposed on the exterior of the engine room (); an aqueous urea tank () storing aqueous urea that purifies the exhaust gas discharged from the engine (); and batteries () supplying electric power to the engine (), wherein: both the aqueous urea tank () and the batteries () are disposed on an upstream side of the heat exchanger () in a flow direction of the outside air.

Construction machine

On the right front side of a revolving frame () constituting an upper revolving structure (), an operating oil tank () and a fuel tank () are arranged. On the front side of this operating oil tank () and the fuel tank (), an equipment accommodating case () forming an accommodating space (A) inside is provided. In the accommodating space (A) in the equipment accommodating case (), a control valve unit () for controlling supply/discharge of the operating oil and a urea water tank () storing urea water for removing nitrogen oxides contained in an exhaust gas of the engine () are arranged together.

On a rear part side of a revolving frame () constituting an upper revolving structure (), a counterweight () holding weight balance with a working mechanism () is provided, and on the front side of the counterweight (), an engine () and an exhaust gas post-treatment device () for applying purification treatment to an exhaust gas of the engine () are provided. The exhaust gas post-treatment device () is configured by connecting a PM trapping filter device () and an NOx purifying device (), and the PM trapping filter device () is mounted on the engine (), while the NOx purifying device () is mounted on the counterweight (). When the counterweight () is to be removed from the revolving frame (), the NOx purifying device () is supported by a treatment device support bracket () mounted on the engine (). As a result, the counterweight () can be removed while the PM trapping filter device () and the NOx purifying device () are connected.

A hydraulic driving device for a working machine surely prevents behavior of a single rod double acting cylinder not intended by an operator when discharge pressure of a main pump is raised to raise exhaust gas temperature to temperature required for burning particulate matter. A selector valveinterposed between a spool valveand a rod chamber of a single rod double acting cylinderand a section (a filter regeneration time actuation valve, a vehicle body controller) controlling the selector valve, are provided. A switch control section prevents a flow of oil directed from the rod chamber of the cylinder toward the spool valve by actuating the selector valve by a poppet of the selector valve when a by-pass cut valveis controlled to increase a load of an engineto a degree exhaust gas temperature reaches temperature required for burning particulate matter.

Hydraulic driving device for working machine

A hydraulic drive device for a construction machine includes an engine stopping unit and a discharge rate control unit. The engine stopping unit stops the engine when a predetermined state of the construction machine has continued for a predetermined period of time. The discharge rate control unit controls a discharge rate control pressure being input to the regulator, when an exhaust emission control device performs regeneration control, or performs warm-up control, and the gate lock lever is in the open position.

Hydraulic drive device for construction machine

A hydraulic drive system realizes a jack-up operation without arrangement of a flow rate control valve and center bypass selector valve. The hydraulic drive system has first and second hydraulic pumps, first and second directional control valves for controlling boom cylinders, a third directional control valve for controlling the boom cylinders, and a third hydraulic pump for feeding pressure oil to the third directional control valve. A jack-up selector valve has a second select position where, when a pressure in bottom chambers of the boom cylinders is not higher than a predetermined pressure, feeding of pressure oil, which is delivered from the first hydraulic pump and second hydraulic pump, to rod chambers of the boom cylinders, is held permissible in association with switching of the second directional control valve and third directional control valve by a manipulation of a control device.

Hydraulic drive device for hydraulic working machine

A hydraulic drive system for a working machine provides improved safety during forced regeneration. Upon input of a forced regeneration command signal from a forced regeneration switch, a controller detects non-operated states of all hydraulic actuators such as an arm cylinder arranged on a hydraulic excavator based on a lock detection signal from a gate lock detection switch, and also an attitude of a front working mechanism. The attitude is proper from the standpoint of safety. The detection is based on an arm angle signal from an arm angle sensor, a bucket angle signal from a bucket angle sensor and a boom pressure signal from a boom pressure sensor. Taking the detection of the non-operated states and proper attitude as conditions, the controller outputs control signals to a boosting proportional solenoid valve and flow-rate controlling, proportional solenoid valve to make a forced regenerator conduct forced regeneration.

Hydraulic drive apparatus for construction equipment

A prime mover revolution speed control system for a hydraulic construction machine sets the revolution speed of the prime mover in accordance with the operating state invoked by an operating command and as a result of a determination of an excavation state so that that the revolution speed of the engine can be increased for a heavy load (speedup) in the excavation state. When the control lever is fully operated in the direction of arm crowding, the control leveris also operated, and first judgment conditions are all met to conclude that an excavation state has begun. During excavation work, when the control leveris subjected to a half or greater operation in the arm crowding direction, second judgment conditions are all met to conclude that the excavation state persists, and the speedup sequence is continued.

Prime mover revolution speed control system for hydraulic construction machine

Disclosed is a hydraulic drive system for a working machine, which enables to conduct forced regeneration continuously for a sufficient time. Based on an input of a lock detection signal Sfrom a gate lock detection switcha controllerdetects that a gate lock leverfor controlling a gate lock on/off valveis in a locked state, in other words, hydraulic actuators such as an arm cylinderarranged on a hydraulic excavatorare all in non-operated states. Upon an input of a forced regeneration command signal So from a forced regeneration switchin this detected state, control signals Cp,Cf are outputted to a boosting control valveand regulatorto make a forced regeneration means (an arm cylinder control valveand the regulator) conduct forced regeneration.

Hydraulic driving device for work machine

An exhaust gas treatment filter removes particulate matter from exhaust gas of a diesel engine. The particulate matter which accumulates on the filter is removed by a manual regeneration system that can simply be controlled. After a manual regeneration switchis shifted to an ON-position, a load control sectionkeeps at least one of the revolution speed N of an engine, the displacement volume q and discharge pressure P of a hydraulic pressure pumpat a corresponding first target value (N, q, or P) or second target value (N, q, or P) depending on a temperature of the cooling water in relation to a flame-out prevention temperature T. A regeneration control sectionstarts the compulsory regeneration after the manual regeneration switch has been shifted to the ON-position and when the cooling water temperature is equal to or higher than T

Working machine

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.

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Tsuchiura, Japan

Kensuke Sato