To solve the problem of hunting phenomenon in which when operation is performed at pressure close to the preset pressure for switching between regenerating and regeneration cut, state is frequently changed over between the regenerating and the regeneration cut to make an arm unstable so that the operation can not be smoothly conducted.
A pressing piston 15 for moving a sub-spool 5 with pressure of a head side oil chamber H of a cylinder S is switched between the energizing state to the pressing piston side both with pilot pressure and the force of a spring 4 and the state of energizing to the pressing piston side only by the force of the spring 4 by a switching mechanism G, whereby a pressure difference is provided between the changing over pressure from the regenerative state to the regeneration cut state and the changing over pressure from the regeneration cut state to the regenerative state, and this pressure difference prevents frequent changing over between the regenerative state and the regeneration cut state.
JP2016205451 | FLUID PRESSURE CIRCUIT AND WORK MACHINE |
WO/2012/055234 | DRIVING AND ENERGY-RECYCLING SYSTEM FOR HYBRID POWER EQUIPMENT |
HIDA KAZUO
Next Patent: REGENERATION SELECTOR VALVE OF HYDRAULIC CYLINDER