摘要:
A hydraulic system for a loader backhoe work machine (10) in which a power unit (14) has a limited output and the pressure relief (100) for the hydraulic actuation system is at a first level for the loader function in which the machine is moved on the ground and a second higher pressure relief for when the backhoe function is being performed.
摘要:
A construction machine includes: a swing structure (20); hydraulic and electric motors (25) mechanically coupled to each other; a hydraulic pump (41) that supplies hydraulic fluid to the hydraulic motor; swing control lever (72) that instructs the swing structure to make a swing motion; and a control device (80) that controls at least either a delivery flow rate of the hydraulic pump or an output torque of the electric motor in such a manner that meter-out and meter-in pressures of the hydraulic motor that is run together with the electric motor approach each other when the demanded torque necessary for the swing motion of the swing structure instructed by the swing control lever can be produced by the electric motor alone.
摘要:
A hydraulic system (28) is provided for a mobile machine (10) having a lift arm (13) attached to a bucket (14) and a transmission (20). The hydraulic system may have a hydraulic actuator (24) configured to move the lift arm and bucket. The hydraulic system may further have an accumulator (56) configured to store pressurized fluid and an accumulator valve (58) configured to control fluid flow between the accumulator and the hydraulic actuator, for a ride control mode of operation configured to cushion movement of the bucket. The hydraulic system may also have a lift arm sensor (66) associated with the mobile machine and configured to generate an angle signal indicative of an angle of the lift arm and a speed sensor (68) associated with the mobile machine and configured to generate a speed signal indicative of the speed of the mobile machine. The hydraulic system may further have a controller (64) in communication with the accumulator valve, the lift arm sensor, the speed sensor, and the transmission. The controller may be configured to receive the speed signal, determine a gear setting of the transmission, and receive the angle signal. The controller may also be configured to selectively activate and deactivate the ride control mode of operation based on the speed of the mobile machine and the angle of the lift arm when the gear setting of the transmission is below a minimum gear setpoint.
摘要:
A construction machine includes: a swing structure (20); hydraulic and electric motors (25) mechanically coupled to each other; a hydraulic pump (41) that supplies hydraulic fluid to the hydraulic motor; swing control lever (72) that instructs the swing structure to make a swing motion; and a control device (80) that controls at least either a delivery flow rate of the hydraulic pump or an output torque of the electric motor in such a manner that meter-out and meter-in pressures of the hydraulic motor that is run together with the electric motor approach each other when the demanded torque necessary for the swing motion of the swing structure instructed by the swing control lever can be produced by the electric motor alone.
摘要:
Provided are an apparatus and a method for variably controlling spool displacement of a construction machine, which are capable of improving regeneration efficiency of the construction machine, and improving a fuel efficiency characteristic of the construction machine by reducing pressure loss in the operating mode by adjusting the quantity of spool displacement in a regeneration mode when a current pressure of a main pump is less than a predetermined operating pressure, and determining whether the construction machine is in an operating mode or the regeneration mode in real time according to an operating angle of a joystick and the current pressure of the main pump when the current pressure of the main pump is greater than or equal to the predetermined operating pressure to variably change the quantity of spool displacement in the operating mode.
摘要:
A hydraulic control system is provided in which hydraulic oil discharged from a variable displacement hydraulic pump is controlled and supplied to a hydraulic actuator by a closed center control valve activated based on operation input from an operation device, thereby controlling activation of the hydraulic actuator. With the pump displacement detected by pump displacement detecting means and the pump output pressure detected by pump output pressure detecting means being used as feedback input and the characteristic value determined by the operation input and the feedback input being used as a target value of a control loop, variable displacement control is performed by a controller provided with a horsepower control loop, a pressure control loop, a flow rate control loop, and a minimum pressure holding loop that feed back a calculated value based on the feedback input or the feedback input itself. The controller is provided with a selector that selects any of the plurality of loops in correspondence with the operation input and the feedback input, so that one loop out of the plurality of loops is selected by the selector and variable displacement control of the hydraulic pump is performed based on the control value from the selected loop.