| 摘要 |
PURPOSE:To perform light steering operation by on/off actuating a control valve that opens and closes a bypass which connects the right and left chambers of a power cylinder to each other using the pump hydraulic pressure and installing a variable throttle in the bypass. CONSTITUTION:A control valve 23 is arranged in a bypass 20 that connects the right and left chambers 15a and 15b of a power cylinder 15 to each other. A pair of valve bodies 21 and 22 are provided in the hole 28 of the mainframe 27 of the control valve 23 so as to be slided freely while they are energized toward both ends by means of a spring 30. A hydraulic pressure signal path that is connected to the side of a tank 12 is connected to the low pressure chamber 32 between both valve bodies 21 and 22. Besides, the said bypass 20 is connected to the high pressure chambers 33a and 33b at the outward ends of the respective valve bodies 21 and 22. Besides, the respective valve bodies 21 and 22 form annular grooves 35 and 36 that are connected to the high pressure chambers 33a and 33b by means of paths 21b and 22b and both grooves 35 and 36 are connected together using a connection path 37. A variable throttle 25 that is controlled by a controller 24 is provided in the connection path 37. |
