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US 10,480,546 B2Granted
Hydraulic cylinder
AssigneeSMC Corporation
InventorsHiroyuki Okuhira, Kenji Imai, Tatsunori Yanase
Life of this patent
Estimating the term…
Abstract
A piston rod and a rod cover which constitute this hydraulic cylinder are configured from aluminum or an aluminum alloy. An alumite coating film is formed on at least a part of the inner wall surface of the rod cover that constitutes a rod insertion hole, and a diamond-like carbon coating film is formed on the outer wall surface of the piston rod, said diamond-like carbon coating film being in sliding contact with the alumite coating film.
Claims2
A fluid pressure cylinder comprising:
- a cylinder main body in which a cylinder hole is formed;
- a piston disposed in the cylinder hole and which is displaced along an axial direction under an action of a working fluid;
- a piston rod connected to the piston;
- and
- a rod cover in which a rod insertion hole is formed through which the piston rod is inserted;
- wherein the piston rod and the rod cover are constituted from aluminum or an aluminum alloy;
- an alumite film or a diamond-like carbon film is formed on at least a portion of an inner wall surface of the rod cover constituting the rod insertion hole;
- in the case that the alumite film is formed on the inner wall surface of the rod cover, a diamond-like carbon film that slides in contact with the alumite film is formed on an outer wall surface of the piston rod, whereas in the case that the diamond-like carbon film is formed on the inner wall surface of the rod cover, an alumite film that slides in contact with the diamond-like carbon film is formed on the outer wall surface of the piston rod;
- an annular groove provided in the inner wall surface of the rod cover;
- a rod packing provided in a portion of the annular groove;
- and
- a lubricant provided in another portion of the annular groove, said another portion of the groove not having the rod packing, whereby said another portion of the groove comprises a lubricant accommodating groove wherein a length of the lubricant accommodating groove in the axial direction is between ⅕ and ⅘ of a length of the alumite film that slides in contact with the diamond-like carbon film,
- wherein said another portion of the annular groove is located at a side of the rod packing which is opposite the piston along the axial direction.
10 more elements
Dependencies are inferred from the claim text.