In a work machine including a controller (500) configured to calculate respective target velocities of a hydraulic cylinder (5) for moving a plurality of work point candidates (8a and 8b) set to a work device along an optionally set target surface (60) on the basis of positional data of the target surface, posture data of the work device (15), and operation data of an operation lever (1), and control the velocity of the hydraulic cylinder (5) according to one of a plurality of the calculated target velocities, the controller calculates a candidate point velocity (VTab or VTba) occurring in a case where each of the plurality of work point candidates is moved at the corresponding target velocity (VTa or VTb) and occurring at a remaining work point candidate, selects a velocity at which an entry into the target surface is least likely from among the plurality of candidate point velocities, and controls the hydraulic cylinder according to the target velocity of the work point candidate associated with the selected candidate point velocity.

A transmission system includes a transmission assembly having clutches to transmit power from an input shaft to an output shaft at a plurality of gear ratios. A traction motor drives the input shaft and propels the work vehicle, while a controller controls operation of the transmission assembly and the traction motor. A hydraulic circuit controls actuation of the clutches responsive to commands from the controller. The hydraulic circuit includes a hydraulic pump driven by the traction motor, an accumulator connected to the hydraulic pump and that holds hydraulic fluid therein under pressure, and an unloading valve positioned in a secondary fluid path running from an outlet of the hydraulic pump to a sump. The unloading valve operates in a closed state to direct hydraulic fluid from the hydraulic pump to the accumulator and operates in an open state to direct hydraulic fluid from the hydraulic pump to the sump.

A working machine includes a switching valve to switch between a first state and a second state, the first state allowing a revolving speed of a traveling motor to be a first speed, the second state allowing the revolving speed of the traveling motor to be a second speed, and a controller device to reduce the revolving speed of the prime mover in either acceleration to switch from the first state to the second state or deceleration to switch from the second state to the first state. The controller device associates a return timing with a switch timing in either the acceleration or deceleration, the return timing allowing an actual revolving speed of a prime mover to start returning toward a first target revolving speed after the actual revolving speed is reduced, the switch timing allowing the switching valve to switch to either an acceleration side or a deceleration side.

There is provided a work machine that can avoid an unintended movement of a blade. A crawler dozer includes a controller. The controller controls EPC valves. A left tilt cylinder and a right tilt cylinder are asymmetrically attached to a blade. The EPC valves control direction and flow rate of supply of hydraulic oil to the right tilt cylinder. The EPC valves control direction and flow rate of supply of the hydraulic oil to the left tilt cylinder. The controller controls the EPC valves and the EPC valves to extend or contract the left tilt cylinder and the right tilt cylinder at different rates.

An apparatus for installing a land anchor of a foundation in an earthen surface includes an articulated arm assembly including a first linear actuator and a drill configured to releasably couple to a helical member, and a control system coupled to the articulated arm assembly and configured to operate the first linear actuator in a free-floating mode configured to maintain an installation angle between the drill and the earthen surface as the helical member is drilled into the earthen surface.

A method for operating a drive system for a work machine is described. A first electric motor is associated with a travel drive of the drive system and a second electric motor is associated with a work drive of the drive system. An electric energy store for operating the first and the second electric motors is associated with the travel drive and the work drive. The method includes operating the first electric motor in generator mode to produce braking power of the travel drive, electric power being produced in the generator mode. The method further includes supplying, completely or partly to the energy store and/or to the second electric motor depending on a state of the energy store, the electric power.

A hydraulic system of a construction machine includes: a pump that supplies hydraulic oil to a hydraulic actuator; a control valve on a center bypass line extending from the pump to a tank, the control valve including a bypass passage; an unloading valve on the center bypass line downstream of the control valve; and a controller that controls the unloading valve. The control valve is configured such that an opening area of the bypass passage is greater than an opening area of the unloading valve while an operation signal outputted from an operation device increases from a predetermined value to a first setting value, and such that the opening area of the bypass passage is less than or equal to ¼ of a maximum opening area of the bypass passage when the operation signal is greater than or equal to a second setting value greater than the first setting value.

A hydraulic circuit of a construction machine includes: a first pump line that connects a delivery port of a pump to a pump port of a first direction-switching valve; a second pump line that is branched off from the first pump line and is connected to a pump port of a second direction-switching valve; and a priority valve provided on the second pump line. The priority valve is configured to: fully open the second pump line when a pressure difference between a delivery pressure of the pump and a load pressure of a first actuator is greater than a setting value; and decrease an opening degree of the second pump line in accordance with decrease in the pressure difference when the pressure difference is less than the setting value.

A hydraulic system controller is disclosed. The hydraulic system controller may determine a maximum active circuit pressure of a set of active hydraulic circuits of the hydraulic system, wherein the hydraulic system includes a hydraulic pump to cause fluid to flow throughout the set of active hydraulic circuits; determine a circuit pressure of a hydraulic circuit of the hydraulic system; determine, based on a hydraulic flow command for the hydraulic circuit and the circuit pressure, a desired circuit delta-pressure for the hydraulic circuit; determine, based on the desired circuit delta-pressure and a pressure difference between the maximum active circuit pressure and the circuit pressure, a circuit valve setting for a circuit valve of the hydraulic circuit; and cause a control device to set a position of the circuit valve according to the circuit valve setting.

Each of left and right direction switching valves includes: a pump port connected to a pump; a first compensation port connected to an upstream side of a corresponding pressure compensation valve; a second compensation port connected to a downstream side of the corresponding pressure compensation valve; a pair of supply/discharge ports connected to a corresponding travel motor; and a communication port. The communication ports of the left and right direction switching valves are connected by a communication line. When a spool shifts from a neutral position by the travel operation device, the pump port communicates with the first compensation port and the second compensation port communicates with one of the supply/discharge ports and the communication port. Each direction switching valve is configured wherein a degree of communication between the second compensation port and communication port increases in a shifting amount of the spool from the neutral position.