Abstract: Provided is a construction machine capable of detecting a stuck-open state of a surplus flow control valve in real time during operation without involving a reduction in the operational speed.

Abstract: A braking distance control device employed for an electrically driven work vehicle includes a safety vehicle speed calculation unit that calculates a safety vehicle speed at which a braking distance provided by use of an electric brake device becomes less than or equal to a threshold value, based on gradient information, payload information, road surface friction information, vehicle speed information, and a braking torque characteristic of electric motors: a critical vehicle speed for deceleration calculation unit that calculates a critical vehicle speed for deceleration at which deceleration provided by use of the electric brake device becomes less than or equal to a threshold value; and an operation judgment unit 14 that judges a setting of notification, based on pedal operation amounts.

Abstract: A right front housing cover is arranged in the right side of a working mechanism, and a first control valve is arranged in a front portion side of a valve accommodation room that is covered with the right front housing cover. Further, a signal control valve block is arranged in the back side of the first control valve and in the upper side of the first control valve, and a solenoid valve is arranged in the back side of the signal control valve block. A front surface plate forming part of the right front housing cover has a lower side is inclined in an oblique downward direction toward the forward side, and is arranged along a virtual line that extends in an oblique downward direction through a front end portion of the first control valve and a front end portion of the signal control valve block.

Abstract: A mount structure for a control valve unit is provided to permit selective mounting of a small first control valve unit or a large second control valve unit on bodies of construction machines of different models the same family without incurring an increase in the number of kinds of parts or components. The control valve unit may be a small first control valve unit or a large second control valve unit. The mount structure is constructed such that upon mounting the first or second control valve unit on a bracket on which the first or second control valve unit may be selectively mounted, a barycentric position of the bracket with the first control valve unit mounted thereon and a barycentric position of the bracket with the second control valve unit mounted thereon are located on an imaginary line connecting paired hanging-member fixing portions of the bracket.

Abstract: A hydraulic drive system comprises directional flow control valves (10a-f) for selectively supplying a hydraulic fluid from a first hydraulic pump (1a, 1b), inflow control valves (201-203) disposed respectively in branch lines (150A-C) branched from a supply line (100) for supplying a hydraulic fluid delivered from a second hydraulic pump (3a, 3b) to rod pushing-side chambers (5aA, 5bA, 6A, 7A) of hydraulic cylinders, a bypass flow control valve (204) disposed in a line (104) connecting the supply line (100) and a reservoir (2), and a controller (31) for computing control variables corresponding to operation command signals from control levers (32, 33) and controlling the inflow control valves (201-203) and the bypass flow control valve (204) 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.