A shovel includes an undercarriage, an upper swing structure swingably mounted on the undercarriage, an object detector provided on the upper swing structure, and a hardware processor configured to automatically braking a drive part of the shovel according to a predetermined braking pattern, in accordance with a distance between the shovel and an object, the distance being detected by the object detector.

A drive control system includes an electric motor, a capacitor, a revolution sensor, a driving device, and a control device. The driving device causes the capacitor to supply electric power to the electric motor to operate the electric motor and causes the capacitor to store the electric power, generated by the electric motor, to brake a turning body. The driving device configured as above is driven by driving electric power supplied from the capacitor. When a charging stop condition is satisfied, the control device stops the driving electric power supplied from the capacitor to the driving device. The charging stop condition is a condition that a turning speed detected by the revolution sensor is a predetermined speed or less while the turning body is decelerating.

A hydraulic device includes: a first block having internal teeth; a second block configured to rotate relative to the first block; an oscillatory rotating body having external teeth smaller in number than the internal teeth, being provided inside the first block such that it is oscillatorily rotatable, and having an inner circumferential portion; a rotation restricting shaft extending from the inner circumferential portion of the oscillatory rotating body in a direction intersecting a radial direction and coupling the oscillatory rotating body and the second block such that they are not allowed to rotate relative to each other while allowing the oscillatory rotating body to oscillatorily rotate; a first friction plate configured to rotate together with the oscillatory rotating body; a second friction plate restricted from rotating by the second or first block; and a press mechanism configured to press the first and second friction plates against each other.

Provided is a hydraulic drive apparatus for a construction machine capable of achieving both of cavitation prevention and improvement of regeneration efficiency. The apparatus includes a regenerative motor configured to regenerate energy of hydraulic fluid discharged from a slewing motor, a first regeneration tank line for returning regeneration discharge fluid from the regenerative motor to a tank through a back pressure valve which is provided in a makeup line, a second regeneration tank line for returning the regeneration discharge fluid directly to the tank so as to bypass the back pressure valve, a regeneration-tank-line selector valve, and a regeneration-tank-line-selection control section configured to shift the regeneration-tank-line selector valve to pass the regeneration discharge fluid through the first regeneration tank line during slewing deceleration and otherwise through the second regeneration tank line.

A hydraulic brake mechanism for use in hydraulic systems to provide braking of a hydraulic motor is disclosed. The brake mechanism provides proper braking under a range of operating conditions, including (1) the start of flow from the pump to the brake and motor and braking is not desired; (2) operating conditions in which constant flow is provided from the pump to the brake and motor and braking is not desired; (3) operating conditions in which abrupt decreases of flow from the pump to the brake and the motor occur, for example where flow is reduced due to being drawn by another work element or hydraulic load, but under which a reduced supply flow is still present and braking is not desired; and (4) operating conditions in which the hydraulic flow from the pump to the brake mechanism and the motor is shut off completely and braking is desired.

A working machine includes a lower body, a turning body, a turning manipulating member which turns the turning body, a hydraulic motor which rotationally drives the turning body, a brake device which brakes the hydraulic motor, amain hydraulic source which supplies hydraulic oil to the hydraulic motor, and a direction control valve which controls a flow direction of the hydraulic oil according to the manipulated variable of the turning manipulating member, in which in a state where the hydraulic motor is braked by the brake device based on a manipulation of a brake manipulating member, when the turning manipulation is performed by the turning manipulating member, a brake applied to the hydraulic motor by the brake device is released with respect to turning in an indication direction indicated by the turning manipulation such that the turning body turns in the indication direction.

A shovel includes a swing hydraulic motor configured to swing a rotating structure, a swing drive hydraulic circuit configured to drive the swing hydraulic motor, an assist hydraulic motor connected to an engine and configured to be supplied with hydraulic oil discharged from the swing drive hydraulic circuit, and a controller configured to control the driving of the shovel. The controller is configured to detect the load condition of the engine, and control the supply of the hydraulic oil to the assist hydraulic motor at the time of deceleration of the swing hydraulic motor, based on the detected load condition.

A rotation drive apparatus for rotating an upper rotary body of a construction machine, the rotation drive apparatus eliminating, while achieving a fundamental goal of stopping a rotation when an emergency stop operation is performed, wasteful stopping by a parking brake. The apparatus includes: an emergency stop switch; a rotation control section which performs control to stop a rotating motor when the emergency stop operation is applied to the emergency stop switch; and a timer which activates the parking brake when a set period of time has elapsed after the emergency stop operation is performed. Preferably, the rotation control section detects a failure of an inverter and causes the parking brake to perform a braking operation before the elapse of the set period of time when the failure is detected.

A shovel includes a lower running body and an upper turning body that is turnably provided on the lower running body. An engine is mounted on the upper turning body. A hydraulic pump is driven by the engine to discharge an operating oil. A hydraulic actuator is mounted on the upper turning body. A control device controls operations of the shovel. An entering object detection device detects a position of an entering object in a monitoring area of said shovel and outputs a detection signal indicating the detection position of said entering object. The control device supplies, after a determination of an entry of the entering object into the monitoring area, the operating oil from the hydraulic pump to the hydraulic actuator.

A turning control apparatus includes a turning body and a hydraulic motor to turn the turning body. A high-pressure relief circuit relieves hydraulic pressure of a first hydraulic line at a first relief pressure, the first hydraulic line supplying an operating oil to drive the hydraulic motor. A hunting reduction circuit relieves a hydraulic pressure of a second hydraulic line at a pressure lower than the first relief pressure, the second hydraulic line being connected to a deceleration-side hydraulic port from which the operating oil is discharged when the hydraulic motor is being driven. The hunting reduction circuit connected to the deceleration-side hydraulic port is caused to open before an operation lever to operate turning of the turning body returns to a neutral position.