An operation control device for a working vehicle comprises a hydraulic actuator to drive the hydraulic working device, operating oil supply source for driving the hydraulic actuator, an operating oil supply control device that performs control to supply operating oil to the hydraulic actuator, an operating device to be operated to make the hydraulic actuator work and a working gain setting device that sets a gain of working speed of the hydraulic actuator corresponding to the operation of the operating device. The operating oil supply control device controls operating oil supply from the operating oil supply source to the hydraulic actuator based on the operation output signal from the operating device and the working speed gain set by the working gain setting device.

A hydraulic excavator (1) includes a controller (40) for generating, when the tip of a work implement (1A) is approaching a target surface (60) due to the pilot pressure output from an operating device (45a, 45b, 46a), a control signal for a boom cylinder (5) such that the tip of the work implement moves along the target surface and controlling the work implement (1A) by outputting the generated control signal to the flow control valve (15a) of the boom cylinder (5). The controller calculates the positional information of a finished shape (97) formed by the work implement, based on the topographic information input from a topographic measurement device (96) that measures the topography near the work machine and corrects the control signal based on the positional information of the finished shape such that the finished shape gets closer to the target surface.

A hydraulic system for a working machine, includes an operation member, an operation valve to change an output pressure of an operation fluid in accordance with operation of the operation member, a hydraulic device to be activated by the operation fluid outputted from the operation valve, a first fluid tube coupling the operation valve to the hydraulic device, and a bleed circuit connected to the first fluid tube and configured to output the operation fluid in the first fluid tube. The first fluid tube includes a first section fluid tube arranged in a section between the operation valve and a coupling portion coupling the first fluid tube to the bleed circuit, and a second section fluid tube arranged in a section between the coupling portion and the hydraulic device, the second section fluid tube having an inner diameter different from an inner diameter of the first section fluid tube.

A work vehicle includes a hydraulic actuator that changes an actual steering angle, an actual steering angle detecting part, an operating unit that performs a steering operation, a position adjusting control part that controls the position adjusting part based on the actual steering angle, and a steering control part that controls the hydraulic actuator. The operating unit includes a support part, a rotating part supported rotatably by the support part, an operating part supported rotatably by the support part or the rotating part, a biasing part that biases the operating part to a predetermined position with respect to the rotating part, a position adjusting part that adjusts a rotation angle of the rotating part with respect to the support part, and a rotation angle detecting part configured to detect the rotation angle of the operating part with respect to the support part or the rotating part.

Provided is a work machine capable of regenerating a return hydraulic fluid from a hydraulic actuator while preventing a drag loss of a regeneration hydraulic motor and a hydraulic pump from increasing and preventing the regeneration efficiency of the regeneration hydraulic motor from decreasing. A controller 100 computes a required regeneration hydraulic motor revolution speed from a displacement of a regeneration hydraulic motor 13 and a regeneration flow rate of the regeneration hydraulic motor, computes a required first hydraulic pump revolution speed from a displacement of a first hydraulic pump 15 and a target assist flow rate of the first hydraulic pump, and selects a greater one of the required regeneration hydraulic motor revolution speed and the required first hydraulic pump revolution speed as a target revolution speed of an electric motor 14.

In a vibration suppression control OFF state, a signal pressure supply control valve stops supplying a first signal pressure, a pressure-regulating valve is in first position where a supply/discharge port connects to a pump port, and an open/close signal pressure is not supplied to an open/close control valve, so an open/close valve is closed. When the OFF state switches to ON state, the signal pressure supply control valve allows supplying the first signal pressure, and the pressure-regulating valve is in second position where the supply/discharge port connects to a tank port, so the pressure of a pressure accumulator decreases. In the ON state, when the pressure of the pressure accumulator is equal to pressure of a pressure chamber, the pressure-regulating valve is in third position where the supply/discharge port is blocked, and the open/close signal pressure is supplied to the open/close control valve, so the open/close valve is opened.

A hydraulic excavator includes: a revolving frame; a work implement including a first actuator and a second actuator; a control valve; and a first pipe through which hydraulic oil flows between the control valve and each of the first actuator and the second actuator. The first pipe includes: a first conduit connected to the control valve; a second conduit and a third conduit that are connected to the first actuator and the second actuator, respectively; and a first branch portion at which the first conduit branches into the second conduit and the third conduit. A first region and a second region are on one side and the other side respectively with respect to the virtual straight line passing through a center of swing of the revolving frame. In the first region, a work implement is disposed. In the second region, the control valve and the first branch portion are disposed.

A wheel loader is provided that can reduce the traveling distance required for a raise and run operation, and reduce fuel consumption. A wheel loader 1 includes: an engine 3; a torque converter 41; a forward and reverse switch 62; a stepping amount sensor 610; an operation amount sensor 73; and a controller 5. The controller 5 determines whether a specific condition for specifying an operation of the lift arm 21 in an upper direction during forward travel of the vehicle body, on the basis of a forward and reverse switching signal, the stepping amount on the accelerator pedal 61, and a pilot pressure Ti pertaining to the lifting operation amount for the lift aim 21. When the specific condition is satisfied, the vehicle speed is limited by reducing the maximum rotational speed of the engine 3 in response to increase in the pilot pressure Ti.

An electromagnetic valve identification device configured to realize individual identification of an electromagnetic valve while suppressing an increase in manufacturing cost. The electromagnetic valve identification device is mounted on an industrial machine, such as a construction machine or an industrial vehicle, configured to move a hydraulic actuator to perform work. The electromagnetic valve identification device includes: an inductance measuring circuit configured to supply an alternating current to a solenoid of an electromagnetic valve of a hydraulic device, the hydraulic device being configured to supply pressure oil to the hydraulic actuator to operate the hydraulic actuator; a calculating portion configured to calculate an inductance of the solenoid based on the alternating current supplied to the solenoid by the inductance measuring circuit; and a storage portion configured to store the calculated inductance of the solenoid as individual identification information of the electromagnetic valve.

A work machine is provided. The work machine includes a changeover valve capable of disabling area limiting control by bypassing an area limiting control solenoid proportional valve disposed in a pilot line through which pilot pressure generated by a hydraulic pilot type operation device is guided to a directional control valve and the work machine can perform the area limiting control while ensuring response of a work implement. When a first fluid temperature T1 is higher than a first predetermined temperature Ta and a control changeover switch 66 specifies disabling of the area limiting control, a controller brings a plurality of changeover valves into a bypass position. When the first fluid temperature T1 is equal to or lower than the first predetermined temperature Ta, the controller brings the changeover valves into a communication position and places the solenoid proportional valves in a fully open position.