Patent ID: 11927205
Assignee: KOMATSU LTD.
Field: Civil engineering (Other fields)
Classification: CPC F  E | IPC E  F

Claim 3:
4. The hydraulic system according to claim 3, further comprising:
an arm excavation first pilot oil passage that applies a pilot pressure to one end part of the arm first direction switching valve when an arm operation lever is subjected to an excavating operation to extend and operate the arm hydraulic cylinder;
an arm excavation second pilot oil passage that applies a pilot pressure to one end part of the arm second direction switching valve when the arm operation lever is subjected to the excavating operation; and
an arm pressure reducing valve interposed in the arm excavation second pilot oil passage,
wherein the arm second direction switching valve blocks the arm second bottom oil passage and the arm second rod oil passage, respectively, when being disposed at a neutral position, and
the controller decompresses the arm excavation second pilot oil passage by the arm pressure reducing valve when the force acting on the piston from the rod chamber exceeds the force acting on the piston from the bottom chamber.