Variable-regeneration directional control valve for construction vehicles

A variable-regeneration directional control valve used in a hydraulic circuit of a construction vehicle, comprising a regeneration passage connected between a return passage and a tank passage, a check valve provided on said regeneration passage for preventing the reverse flow of fluid from a supply passage to the return passage through said regeneration passage, a regeneration switching spool movably arranged in a valve block between said regeneration passage and said tank passage in order to control a cross-sectional area of the fluid passage inside the control valve, said spool linearly moving in the valve block by the relation between a self pressure inside a supply line and an opposite pressure caused by elasticity of a valve spring, thus controlling the amount of regenerated fluid, further comprising:

• means for linearly moving in said control valve in response to an outside control signal and appropriately changing the opposite pressure caused by elasticity of the valve spring and thereby controlling a regeneration canceling pressure, said means being provided an end tip of said valve spring determining a switching pressure of said spool.