Abstract: An efficient and quiet construction machine has a heat exchanger in which the air flowing out from an axial flow fan avoids collision with the engine. The axial flow fan includes a plurality of blade pieces, a fan ring which guides a flow of air to the axial flow fan, a heat exchanger which is disposed on an upstream side or a downstream side of the flow of air with respect to the axial flow fan, and a structure which is disposed on the downstream side of the flow of air with respect to the axial flow fan. The fan ring includes a suction-side rounded part which reduces a flow channel on a suction side and a discharge-side rounded part which expands the flow channel on a discharge side, and each of the blade pieces is inclined at a sweep forward angle from an axial center toward a rotation direction.

Abstract: 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.

Abstract: A mounting structure for an NOx reduction system for a construction machine is provided for relaxing restrictions on a space for the arrangement of the NOx reduction system. The mounting structure includes a urea-water SCR catalyst for reducing and purifying nitrogen oxides emitted from an engine, a urea water spray device for spraying urea water into an exhaust passage of the engine, a urea water feeder for feeding the urea water to the urea water spray device, a first urea-water tank and second urea-water tank for storing the urea water to be guided to the urea water feeder, and a controller for controlling drive of the urea water spray device and urea water feeder. A counterweight is provided with a cavity formed therein, the urea water feeder, first urea-water tank, second urea-water tank and controller are integrally arranged as an assembly arranged in the cavity of the counterweight.

Abstract: Disclosed is a working machine capable of preventing damage to a filter due to excessive accumulation of particulate matter (PM), even under a situation that requires, prior to compulsory regeneration of the filter, moving the machine to a place in which to perform the regeneration work. The working machine that includes an exhaust treatment device 4 having a filter 6 to trap the PM, a regeneration control section 31 for compulsorily regenerating the filter, and a regeneration instruction device 23 for instructing the regeneration control section 31 to start the compulsory regeneration. Further, when a deposition quantity estimating element determines that an actual PM deposition quantity has reached a deposition alarm level, an alarm device 12 notifies an operator that the time has come to start the movement of the working machine to the place of regeneration.

Abstract: An upstream cylinder (21) and a downstream cylinder (24) are fixedly mounted to a support member (19), and a filter cylinder (26) is provided mountably and dismountably between the cylinders (21) and (24). In consequence, only the filter cylinder (26) can be dismounted with the cylinders (21) and (24) left as they are on the support member (19), so that the maintenance operation of a particulate matter removing filter (28) can be performed easily. In addition, pressure conduits (32) and (33) and a pressure sensor (34) of a pressure detection unit (31) for detecting a clogged state of the particulate matter removing filter (28) are disposed at positions offset from a moving path (30) of the filter cylinder (26). In consequence, only the filter cylinder (26) can be easily mounted or dismounted without being obstructed by the pressure conduits (32) and (33) and the pressure sensor (34).

Abstract: 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.

Abstract: An upstream cylinder (21) and a downstream cylinder (24) are fixedly mounted to a support member (19), and a filter cylinder (26) is provided mountably and dismountably between the cylinders (21) and (24). In consequence, only the filter cylinder (26) can be dismounted with the cylinders (21) and (24) left as they are on the support member (19), so that the maintenance operation of a particulate matter removing filter (28) can be performed easily. In addition, pressure conduits (32) and (33) and a pressure sensor (34) of a pressure detection unit (31) for detecting a clogged state of the particulate matter removing filter (28) are disposed at positions offset from a moving path (30) of the filter cylinder (26). In consequence, only the filter cylinder (26) can be easily mounted or dismounted without being obstructed by the pressure conduits (32) and (33) and the pressure sensor (34).

Abstract: Disclosed is a working machine capable of preventing damage to a filter due to excessive accumulation of particulate matter (PM), even under a situation that requires, prior to compulsory regeneration of the filter, moving the machine to a place in which to perform the regeneration work. The working machine that includes an exhaust treatment device 4 having a filter 6 to trap the PM, a regeneration control section 31 for compulsorily regenerating the filter, and a regeneration instruction device 23 for instructing the regeneration control section 31 to start the compulsory regeneration. Further, when a deposition quantity estimating element determines that an actual PM deposition quantity has reached a deposition alarm level, an alarm device 12 notifies an operator that the time has come to start the movement of the working machine to the place of regeneration.

Abstract: [Problem] To provide a mounting structure for an NOx reduction system for a construction machine, said mounting structure being capable of relaxing restrictions on a space for the arrangement of the NOx reduction system.