| 摘要 |
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. The hydraulic circuit includes a variable displacement hydraulic pump, an option device connected to the hydraulic pump, a first spool, installed in a flow path between the hydraulic pump and the option device, for being shifted in response to a pilot signal pressure applied from an outside to control a flow rate applied from the hydraulic pump to the option device, a poppet, operatively installed in a flow path between the hydraulic pump and the first spool, for supplying hydraulic fluid to the option device when the first spool is shifted, a piston resiliently urged in a back pressure chamber of the poppet, and a second spool for being shifted by a pressure difference between pressures of the hydraulic fluid before and after the hydraulic fluid passes through the first spool, and controlling the flow rate applied to the back pressure chamber of the poppet via a through-path communicating with the back pressure chamber when the second spool is shifted.
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