An apparatus for retaining an upper pivoting body of a construction machine having a lower traveling body includes a protrusion on a lower surface of the upper pivoting body, a socket portion on an upper side of the lower traveling body that couples with the protrusion, an elastic member on a lower side of the socket portion that elastically supports the socket portion, a first tapered member on a lower side of the elastic member to support the elastic member, a lower surface of the first tapered member having a sloping surface, and a second tapered member on a lower side of the first tapered member. The upper surface of the second tapered member has a sloping surface that makes sliding contact with the first tapered member. The second tapered member lifts the socket portion, through a horizontal movement, to be coupled with the protrusion or lowers the socket portion to be separated from the protrusion.

A hydraulic excavator (1) includes a wireless authentication device (52) performing wireless authentication with a portable key device (51) and a vehicle body controller (48) for starting an engine (15) based on authentication by the wireless authentication device (52) and an operation of a start switch (12). The wireless authentication device (52) transmits a request signal within an authenticable range and performs authentication when it receives an ID code for authentication replied from the portable key device (51) based on the transmitted request signal. The vehicle body controller (48) prohibits driving of a hydraulic actuator (5E, 5F, 5G, 5H, 2E, 2F, 3A) when the portable key device (51) is outside of the authenticable range even if a gate lock lever (13) has been switched to an unlock position.

A hydraulic system of a construction machine includes: control valves interposed between a main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a brake for a slewing motor; and a second solenoid proportional valve connected to a brake release port of the brake by a secondary pressure line and connected to an auxiliary pump by a primary pressure line. A switching valve including a pilot port connected to the secondary pressure line by a pilot line is interposed between the auxiliary pump and the first solenoid proportional valves.

A hydraulic system of a construction machine includes: control valves interposed between a main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a brake for a slewing motor; and a second solenoid proportional valve connected to a brake release port of the brake by a secondary pressure line and connected to an auxiliary pump by a primary pressure line. A switching valve including a pilot port connected to the secondary pressure line by a pilot line is interposed between the auxiliary pump and the first solenoid proportional valves.

Provided is a slewing-type working machine including: a slewing motor; a capacity control device; a slewing control device operated by a slewing instruction operation to allow hydraulic fluid to be supplied from a hydraulic pump to the slewing motor; a slewing parking brake; a brake switching device; a brake release instruction unit which inputs a brake release instruction to the brake switching device so as to make the brake switching device switch the slewing parking brake to a brake releasing state after allowing hydraulic fluid to be supplied to the slewing motor; and a capacity limiting unit that limits the capacity of the slewing motor controlled by the capacity control device to a predetermined brake-release capacity value or less until a brake release point and allows the capacity to increase after the brake release point.

An electric motor includes a rotor having a rotary shaft rotating around a vertically extending axis and a rotor core fixed to an outer peripheral surface of the rotary shaft, a stator surrounding the rotor core from an outer peripheral side, a lower bottom portion as a partition wall partitioning a first space where the rotor and the stator are disposed and a lubricating oil is supplied from an outside, a storage portion configured to store the lubricating oil supplied into the first space, a brake mechanism as a drive unit discharging the lubricating oil inside the storage portion into the first space, and sliding portions into each of which the lubricating oil discharged from the inside of the storage portion is introduced.

Provided is a parking brake apparatus installable on a work machine. The parking brake apparatus includes: a parking brake switchable between a braking state of braking the turning of an upper turning body and a braking release state; a brake operation device to which a braking operation and a braking release operation for switching the parking brake to the braking state and the braking release state, respectively, is applied by an operator; and a braking control unit. The braking control unit judges whether or not a turning judgment requirement for judging whether or not the upper turning body is performing a turning motion is satisfied, and performs a braking operation invalidation control to invalidate the braking operation applied to the brake operation device when judging the turning motion is being performed.

To provide an identification system for a work machine which is capable of preventing a setting error, the identification system for a work machine includes: a main control unit to control the entirety of a work machine; and a plurality of power control units to control components of the work machine. The main control unit acquires information about the entire vehicle body of the work machine. Each of the power control units acquires different information about a state of one of the components from that acquired by the other power control units, on the basis of a installation site of the power control unit installed on the work machine. In addition, the power control unit sets a function of the power control unit on the basis of the information about the state and the information about the entire vehicle body.

Provided is a slewing-type working machine including: a slewing motor; a capacity control device; a slewing control device operated by a slewing instruction operation to allow hydraulic fluid to be supplied from a hydraulic pump to the slewing motor; a slewing parking brake; a brake switching device; a brake release instruction unit which inputs a brake release instruction to the brake switching device so as to make the brake switching device switch the slewing parking brake to a brake releasing state after allowing hydraulic fluid to be supplied to the slewing motor; and a capacity limiting unit that limits the capacity of the slewing motor controlled by the capacity control device to a predetermined brake-release capacity value or less until a brake release point and allows the capacity to increase after the brake release point.

A working machine includes a traveling device having a traveling frame, a turn base plate supported on the traveling frame and configured to turn around an axis extending in a vertical direction, the turn base plate having an opening portion through which the axis extends, and a swivel joint including an outer sleeve fixed to the turn base plate, and an inner shaft inserted to the opening portion and inserted to the outer sleeve so as to rotate about the axis, the inner shaft being configured to restrictively rotate with respect to the traveling frame. The outer sleeve has a flange portion fixed to the turn base plate on a periphery of the opening portion and covering the opening portion.