| 摘要 |
PURPOSE:To prevent the rust formation of a piston rod by arranging a rustproof member made of the metal material having the larger ionization tendency than that of the material of a piston rod on the outer periphery of the piston rod. CONSTITUTION:When muddy water, etc., adheres on a piston rod 2, a small cell called local cell is formed, having the muddy water as electrolyte, and since a collar 4 which is constituted of zinc material has the larger ionization tendency than that of a piston rod 2 which is constituted of iron material, the electric potential is lowered, and the electric potential which is larger than the electric potential to be generated within the piston rod 2 is generated between the piston rod 2 and the collar 4. Accordingly, electrons flow to the high potential part of the piston rod 2 from the collar 4 having the lower potential, and rust is generated on the collar 4 which forms the low potential side. Accordingly, at the sacrifice of the collar 4, the rust formation of the piston rod 2 can be prevented. |
