WORKING OIL FOR HYDRAULIC SHOCK ABSORBER, AND HYDRAULIC SHOCK ABSORBER

摘要

[Problem] To provide a working oil for shock absorbers which is inhibited from affecting rubber materials. [Solution] A working oil which comes into contact with a rubber material, characterized by comprising a polyalkylene glycol and one or more base oils selected from among fatty acid diesters, poly(α-olefin)s, and the lubricating oils classified as GIII by American Petroleum Institute (API). With this working oil, it is possible to reduce the degree of swelling of rubber materials such as sealing materials and hence use conventional rubber materials as they are.