PISTON ROD HAVING LUBRICANT PASSAGE FOR HYDRAULIC CYLINDER

摘要

PURPOSE: A piston rod having a lubricant passage is provided to always lubricate the piston rod and a seal unit by forming a third chamber communicated with a second chamber in the piston rod. CONSTITUTION: In a hydraulic cylinder(300), a second chamber(103) in a housing(100) is filled with lubricating oil for lubricating the outer circumference of a piston rod(200). A third chamber(201) is formed in the piston rod, and is communicated with the second chamber to replenish the second chamber with lubricating oil or contain the lubricating oil in the second chamber.