Shock absorber and hydraulic oil for shock absorber

Abstract

This shock absorber includes: a bottomed cylindrical cylinder; an oil seal member containing acrylonitrile-butadiene rubber at an opening of the cylinder; and a hydraulic oil sealed within the cylinder, in which the hydraulic oil contains a base oil and an additive added to the base oil, and the base oil contains a first fluid having a first viscosity and being a plant-derived fat and oil in which the number of molecules of polyunsaturated fatty acid groups contained in the total triglyceride content is greater than the number of molecules of monounsaturated fatty acid groups, and a second fluid having a second viscosity lower than the first viscosity and containing a fatty acid ester.

Dependencies are inferred from the claim text.