Abstract: A hydraulic control valve for heavy equipment is provided, which includes a valve body having a supply passage supplied with a hydraulic fluid from a hydraulic pump, ports for supplying the hydraulic fluid to an actuator or receiving the hydraulic fluid from the actuator, tank passages for returning the hydraulic fluid from the actuator to a hydraulic tank, and a first regeneration passage for supplying a part of the returned hydraulic fluid to the supply passage; a spool slidably installed in the valve body in accordance with supply of a pilot signal pressure from an exterior, and controlling flow of the hydraulic fluid supplied to the actuator from the supply passage during shifting; and a regeneration valve installed between the first regeneration passage and the tank passage, and including a piston moved by the hydraulic fluid from the hydraulic pump, a regeneration spool shifted by pressure fluctuation of the supply passage to variably adjust a flow rate of the hydraulic fluid discharged from the first r

Abstract: A pressure control valve is provided, which can variably control the set pressure of a relief valve in accordance with pilot signal pressure that is controlled in an operator's seat and so on when the set pressure of the relief valve required in a replaced working device is changed.

Abstract: A hydraulic circuit of an option device for an excavator is disclosed, which can constantly supply hydraulic fluid to an option device, such as a breaker and so on, selectively mounted on the excavator, irrespective of the size of a load occurring when the option device operates, and control respective flow rates required for various kinds of option devices. The hydraulic circuit includes a variable hydraulic pump, an option device, a first spool shifted to control hydraulic fluid fed to the option device, a poppet and a piston, an option spool shifted to control hydraulic fluid fed to the option device via the first spool, a second spool shifted to control hydraulic fluid fed to a back pressure chamber of the poppet, and a control means installed in the poppet and controlling hydraulic fluid passing through an orifice of the poppet when the piston and the poppet are pressed by the hydraulic fluid fed from the hydraulic pump, through the shifting of the second spool.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent an energy loss of a hydraulic system by automatically reducing revolution of an engine when a working device such as a boom is not driven. The hydraulic circuit includes first to third hydraulic pumps, first to third switching valves for controlling hydraulic fluid fed to working devices, a fourth switching valve for controlling hydraulic fluid fed to left and right traveling devices, a confluence switching valve for selectively supply the hydraulic fluid from the third hydraulic pump to either the working devices on the first hydraulic pump side or the working devices on the second hydraulic pump side, a signal line for traveling devices, signal lines for working devices, and a shuttle valve for selecting any one of the signal pressure formed in the signal line for the traveling devices and the signal pressure formed in the signal lines for the working devices.

Abstract: A straight traveling hydraulic circuit is disclosed, which, in the case of performing a combined operation in which working and traveling devices are simultaneously driven, can prevent a declination of equipment due to an overload of the working devices. A straight traveling valve is shifted to supply the hydraulic fluid from the first hydraulic pump to the left and right traveling motors and to supply the hydraulic fluid from the second hydraulic pump to the first and second working devices. A control valve connects inlet and outlet parts of the straight traveling valve, and is shifted, when the combined operation is performed, to intercept a supply of the hydraulic fluid from the second hydraulic pump to the traveling motor.

Abstract: A pressure control valve is provided, which can variably control the set pressure of a relief valve in accordance with pilot signal pressure that is controlled in an operator's seat and so on when the set pressure of the relief valve required in a replaced working device is changed.

Abstract: A hydraulic control valve for heavy equipment is provided, which includes a valve body having a supply passage supplied with a hydraulic fluid from a hydraulic pump, ports for supplying the hydraulic fluid to an actuator or receiving the hydraulic fluid from the actuator, tank passages for returning the hydraulic fluid from the actuator to a hydraulic tank, and a first regeneration passage for supplying a part of the returned hydraulic fluid to the supply passage; a spool slidably installed in the valve body in accordance with supply of a pilot signal pressure from an exterior, and controlling flow of the hydraulic fluid supplied to the actuator from the supply passage during shifting; and a regeneration valve installed between the first regeneration passage and the tank passage, and including a piston moved by the hydraulic fluid from the hydraulic pump, a regeneration spool shifted by pressure fluctuation of the supply passage to variably adjust a flow rate of the hydraulic fluid discharged from the first r

Abstract: A relief valve for heavy equipment is provided, which can prevent leakage of oil due to a secession of a guide that is released when pressure is set in order to re-set the set pressure of a relief valve for maintaining a set pressure of a hydraulic circuit, and can prevent damage of an O-ring mounted to seal a gap between contact surfaces.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent an energy loss of a hydraulic system by automatically reducing revolution of an engine when a working device such as a boom is not driven. The hydraulic circuit includes first to third hydraulic pumps, first to third switching valves for controlling hydraulic fluid fed to working devices, a fourth switching valve for controlling hydraulic fluid fed to left and right traveling devices, a confluence switching valve for selectively supply the hydraulic fluid from the third hydraulic pump to either the working devices on the first hydraulic pump side or the working devices on the second hydraulic pump side, a signal line for traveling devices, signal lines for working devices, and a shuttle valve for selecting any one of the signal pressure formed in the signal line for the traveling devices and the signal pressure formed in the signal lines for the working devices.

Abstract: Disclosed is a hydraulic circuit for an option device of heavy construction equipment which can facilitate manipulation of the option device such as a breaker and optionally control a flow rate by supplying hydraulic fluid from a hydraulic pump to the option device at a constant flow rate, regardless of the size of load produced on the option device.

Abstract: A hydraulic circuit of an option device for an excavator is disclosed, which can constantly supply hydraulic fluid to an option device, such as a breaker and so on, selectively mounted on the excavator, irrespective of the size of a load occurring when the option device operates, and control respective flow rates required for various kinds of option devices. The hydraulic circuit includes a variable hydraulic pump, an option device, a first spool shifted to control hydraulic fluid fed to the option device, a poppet and a piston, an option spool shifted to control hydraulic fluid fed to the option device via the first spool, a second spool shifted to control hydraulic fluid fed to a back pressure chamber of the poppet, and a control means installed in the poppet and controlling hydraulic fluid passing through an orifice of the poppet when the piston and the poppet are pressed by the hydraulic fluid fed from the hydraulic pump, through the shifting of the second spool.

Abstract: A straight traveling hydraulic circuit is disclosed, which, in the case of performing a combined operation in which working and traveling devices are simultaneously driven, can prevent a declination of equipment due to an overload of the working devices. The straight traveling hydraulic circuit includes first and second variable hydraulic pumps, a left traveling motor and a first working device connected to the first hydraulic pump, switching valves installed in a flow path of the first hydraulic pump, a right traveling motor and a second working device connected to the second hydraulic pump, switching valves installed in a flow path of the second hydraulic pump, a straight traveling valve installed in the flow path of the second hydraulic pump, and a control valve installed in a branch flow path branched from the flow path of the second hydraulic pump.

Abstract: The present invention A hydraulic control valve with a regeneration function, including a main body formed of a supply fluid passage to which pressurized fluid is supplied, at least one port, a tank fluid passage for discharging the pressurized fluid to an outside storage tank, and a first regeneration fluid passage; a spool movably installed inside the main body for controlling the flow of the pressurize fluid, and including a second generation fluid passage formed therein; and a regeneration valve for returning only part of the pressurized fluid of the first regeneration fluid passage to the tank fluid passage to maintain pressure of the first regeneration fluid passage at a designated value, and for supplying the pressurized fluid to the second regeneration fluid passage, and if the pressure of the supply fluid passage is higher than a predetermined pressure, changing the pressure of the first regeneration fluid passage in accordance with a change of the pressure of the supply fluid passage.

Abstract: Disclosed is a hydraulic control valve having a holding valve with improved response characteristics.

Abstract: The present invention is directed to controlling an operation oil supplied to an option apparatus without changing a design of a control valve assembly which controls an operation oil supplied to a traveling motor, etc. when additionally engaging an option apparatus to a small size excavator.

Abstract: Disclosed is a hydraulic circuit for an option device of heavy construction equipment which can facilitate manipulation of the option device such as a breaker and optionally control a flow rate by supplying hydraulic fluid from a hydraulic pump to the option device at a constant flow rate, regardless of the size of load produced on the option device.

Abstract: Disclosed is a variable regeneration valve of a heavy equipment in which hunting due to repeated motion of a spool does not occur in a regeneration valve that supplies a return flow of an actuator to a supply port during single operation of the actuator or its composite operation such as composite driving of arm in and swing, and a structure of the variable regeneration valve is simplified to improve process characteristics. The variable regeneration valve includes a hydraulic pump, an actuator connected with the hydraulic pump, a control valve controlling operation, stop, and direction of the actuator, a regeneration switching valve having a first piston, a switching spool, a first elastic member, and a second piston, a first damping orifice, and a second damping orifice.

Abstract: The present invention A hydraulic control valve with a regeneration function, including a main body formed of a supply fluid passage to which pressurized fluid is supplied, at least one port, a tank fluid passage for discharging the pressurized fluid to an outside storage tank, and a first regeneration fluid passage; a spool movably installed inside the main body for controlling the flow of the pressurize fluid, and including a second generation fluid passage formed therein; and a regeneration valve for returning only part of the pressurized fluid of the first regeneration fluid passage to the tank fluid passage to maintain pressure of the first regeneration fluid passage at a designated value, and for supplying the pressurized fluid to the second regeneration fluid passage, and if the pressure of the supply fluid passage is higher than a predetermined pressure, changing the pressure of the first regeneration fluid passage in accordance with a change of the pressure of the supply fluid passage.

Abstract: Disclosed is a hydraulic control valve having a holding valve with improved response characteristics.

Abstract: The present invention is directed to controlling an operation oil supplied to an option apparatus without changing a design of a control valve assembly which controls an operation oil supplied to a traveling motor, etc. when additionally engaging an option apparatus to a small size excavator.