A hydraulic system includes a first and a second rotating hydraulic machine, the first and second hydraulic machine being arranged to provide a torque via a common output shaft; a first valve arrangement for providing a differential hydraulic pressure level over the first hydraulic machine by using two sources of hydraulic fluid having different hydraulic pressure levels, a second valve arrangement for providing a differential hydraulic pressure level over the second hydraulic machine by using two sources of hydraulic fluid having different hydraulic pressure levels; and a control unit configured to control the first valve arrangement and the second valve arrangement such that different discrete levels of torque are provided via the output shaft of the hydraulic system. A hydraulic system for providing different discrete levels of torque using one hydraulic machine and a plurality of differential pressure levels, and a method for controlling a hydraulic system, are also provided.

A shovel includes a lower traveling body, an upper swiveling body that is rotatably mounted on the lower traveling body, and a controller configured to perform straight facing control by which an actuator is operated to cause the upper swiveling body to face a target construction surface straight, based on information related to the target construction surface and information related to a direction of the upper swiveling body.

A mobile apparatus includes a main frame, an operating arm connected to the main frame, drive means configured to drive displacing means of the mobile apparatus, such as one or more wheels or tracks, drive means configured to drive the operating arm and a control system, connected to operating instruments for a driver, for controlling the drive means. The drive means for the displacing means includes an electric motor such that the drive of the displacing means is substantially electrical.

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 pressure medium cylinder (1) for moving a toothed bar (3), comprising a toothed bar (3) on at least one side of which is formed a toothing (4). Inside the toothed bar (3), a cavity (6, 6a, 6b) is formed, extending to at least one end (7a, 7b) of the toothed bar. The pressure medium cylinder (1) further comprises a longitudinal structure (8, 8a, 8b), the longitudinal structure (8, 8a, 8b) and the toothed bar (3) being adapted movably in relation to each other, and the longitudinal structure (8, 8a, 8b) is adapted at least partly inside said cavity (6, 6a, 6b). The toothed bar (3) and longitudinal structure (8, 8a, 8b) are adapted in a sealed manner in relation to each other so that the toothed bar and the longitudinal structure are movable in relation to each other by the effect of a pressure medium.

A pump that supplies hydraulic oil to a boom cylinder and a turning hydraulic motor; a regenerative hydraulic motor is coupled to the pump and to which the hydraulic oil discharged from the boom cylinder at a time of boom lowering and/or the hydraulic oil discharged from the turning hydraulic motor at a time of turning deceleration is/are led; an engine drives the pump; an alternator mounted to the engine and operable to rotate an output shaft of the engine when electric power is supplied to the alternator; an electrical storage device connected to the alternator; a power converter interposed between the alternator and the electrical storage device; and a controller that switches the power converter to either a servo-on state or a servo-off state and that controls the power converter either in a charging mode or in a discharging mode when switching the power converter to the servo-on state.

A pivot control apparatus of construction equipment is provided for reaching a desired swing angle by controlling the brake torque of a swing motor during a loading operation using an excavator, along with a control method therefor. The swing control apparatus of construction equipment according to one embodiment of the present invention includes first and second hydraulic pumps and a pilot pump; a boom cylinder, an arm cylinder, and a bucket cylinder which are driven by the hydraulic fluid of the first and second hydraulic pumps; an operation apparatus control valve for controlling the hydraulic fluid which is supplied from the first and second hydraulic pumps to the boom cylinder, the arm cylinder and the bucket cylinder; a swing motor Which is driven by the hydraulic fluid of any one of the first and second hydraulic pumps to swing an upper swinging, body; a swing control valve; a swing operation lever, a direction control valve which applies a pilot pressure to the swing control valve according to the swing operation lever or a semi-automatic swing mode selection; electronic proportional variable relief valves capable of variably adjusting the relief setup pressure of the swing motor; and a controller which, when a semi-automatic swing mode is selected and the operation apparatus is actuated at the time of swing return, applies an electric signal to the variable relief valve at the outlet side, from among the electronic proportional variable relief valves, so as to increase or decrease the relief setup pressure.

The present invention includes: a base carrier; a revolving superstructure provided above the base carrier in a manner capable of revolving; a boom bracket supported by the revolving superstructure in a horizontally rotatable manner; a work machine supported by the boom bracket in a vertically rotatable manner; a first position detecting device that detects a horizontal position of the boom bracket with respect to the revolving superstructure; a second position detecting device that detects a vertical position of the work machine with respect to the revolving superstructure; and an arithmetic unit that calculates a position of a working end of the work machine based on the results of detection by those position detecting devices.

At least some embodiments of the present disclosure are directed to distributed pump architectures used in control systems for multifunctional machines. In some cases, a control system for a multifunctional machine includes three or more control circuits. At least two of the control circuits each has a hydraulic fluid pump and each of the pumps is controlled by a different control circuit. At least two of the hydraulic fluid pump have different flow rates.

An excavator includes at least one gyro sensor for sensing the incline of equipment; a swing motor for rotating an upper body of the excavator; a first pressure sensor for sensing an operating pressure value applied to the swing motor; a swing joystick for driving the swing motor; a second pressure sensor for sensing a manipulation value inputted into the swing joystick; and a controller, wherein the controller receives pieces of information sensed by the gym sensors, the first pressure sensor, and the second pressure sensor, and detects the operating pressure value of the swing motor, sensed through the first pressure sensor, so as to notify a worker of the time at which lubricating oil is added if a maximum manipulation value is inputted into the swing joystick for a minimum measuring time or more in a swing friction force measurement mode.