Abstract: A control valve is provided for construction equipment having a holding valve which prevents the natural lowering of an operation apparatus due to the dead weight of the operation apparatus when an actuator is in a neutral position. The control valve includes a valve body, a spool, a holding valve, a control valve, and a pilot pressure control valve. The control valve can save manufacturing cost as well as allow better use of space for construction equipment.

Abstract: Disclosed is a flow control valve for a construction equipment for controlling the amount of oil supplied to a hydraulic actuator from a hydraulic pump.

Abstract: A control valve is provided for construction equipment having a holding valve which prevents the natural lowering of an operation apparatus due to the dead weight of the operation apparatus when an actuator is in a neutral position.

Abstract: Disclosed is a hydraulic system for performing land preparation works by means of a simultaneous boom-up and arm-in operation.

Abstract: Disclosed is a flow control valve for a construction equipment for controlling the amount of oil supplied to a hydraulic actuator from a hydraulic pump.

Abstract: A pressure control valve for a construction machine is disclosed, which prevents self-weight descent of a working device due to leakage of hydraulic fluid in a neutral position of the working device.

Abstract: Disclosed is a flow control valve for construction equipment capable of effectively operating travelling and working apparatuses when the construction equipment performs complex work by operating the working apparatus while travelling.

Abstract: Disclosed is a hydraulic circuit for a pipe layer, in which the generation of hydraulic shock in equipment is prevented when an operating device or a moving device is finely operated during combined work in a pipe-laying operation mode.

Abstract: A pressure control valve for a construction machine is disclosed, which prevents self-weight descent of a working device due to leakage of hydraulic fluid in a neutral position of the working device.

Abstract: A flow control valve for a construction machine is provided, which can constantly control a flow rate of hydraulic fluid supplied to a hydraulic actuator through a flow control spool in a spool. The flow control valve for a construction machine, having a valve body in which a supply passage communicating with a pump passage and actuator ports connected to a hydraulic actuator are formed, and a spool installed in the valve body to be shifted, includes a flow control spool shifted in the spool to variably control a cross-sectional area of a passage connected to the one actuator port if a flow rate of the hydraulic fluid that flows through the supply passage is higher than a set flow rate, a first passage formed on the spool to communicate with the supply passage and a second passage formed on the spool to communication with the one actuator port and having a cross-sectional area that is varied depending on the shifting of the flow control spool.

Abstract: Disclosed is a hydraulic system for performing land preparation works by means of a simultaneous boom-up and arm-in operation.

Abstract: A travel control system is disclosed for preventing off-course travel of equipment due to the overloading of a working piece such as a boom during a complex operation involving vehicle travel and simultaneous driving of the working piece.

Abstract: A pressure control valve is provided, which includes a stopper having a flow path for preventing damping that is provided in a contact portion that is adjacent to an inner flow path of a main piston so that hydraulic fluid in the main piston is smoothly drained through a gap between stopper contact surfaces.

Abstract: Disclosed is a hydraulic circuit for a pipe layer, in which the generation of hydraulic shock in equipment is prevented when an operating device or a moving device is finely operated during combined work in a pipe-laying operation mode.

Abstract: The present invention relates to a holding valve that is used for a hydraulic circuit for controlling a working device actuator of construction equipment, and to a holding valve for construction equipment in which a double nut and a sleeve are removed such that an assembling efficiency is improved and the cost is reduced, and further, the abnormal assembling of a piston can be prevented.

Abstract: A flow control valve for a construction machine is provided, which can constantly control a flow rate of hydraulic fluid supplied to a hydraulic actuator through a flow control spool in a spool. The flow control valve for a construction machine, having a valve body in which a supply passage communicating with a pump passage and actuator ports connected to a hydraulic actuator are formed, and a spool installed in the valve body to be shifted, includes a flow control spool shifted in the spool to variably control a cross-sectional area of a passage connected to the one actuator port if a flow rate of the hydraulic fluid that flows through the supply passage is higher than a set flow rate, a first passage formed on the spool to communicate with the supply passage and a second passage formed on the spool to communication with the one actuator port and having a cross-sectional area that is varied depending on the shifting of the flow control spool.

Abstract: A pressure control valve is provided, which includes a stopper having a flow path for preventing damping that is provided in a contact portion that is adjacent to an inner flow path of a main piston so that hydraulic fluid in the main piston is smoothly drained through a gap between stopper contact surfaces.

Abstract: A pressure control valve is provided, which can variably control the set pressure of the pressure control valve through manipulation of a signal pressure generation device in an operator's seat or the like.