| 摘要 |
PROBLEM TO BE SOLVED: To prevent seizure caused by the shortage of lubricating oil by making the lubricating oil sufficiently spread over a surface on which a swing bush and a piston are brought into slide-contact with each other.SOLUTION: A swing bush (45) is arranged in a portion of a piston (40) which a blade (35) penetrates. A bush-side oil supply hole (46) is formed in the swing bush (45). One end of the bush-side oil supply hole (46) is opened on a slide-contact surface on the blade (35) side, and the other end is opened on a slide-contact surface on the piston (40) side. A blade-side oil supply hole (36) is formed in the blade (35). One end of the blade-side oil supply hole (36) communicates with an oil passage (16), and the other end is opened on a slide-contact surface on the swing bush (45) side and communicates with the bush-side oil supply hole (46). |
