Hydraulic oil composition

Abstract

A hydraulic oil composition obtained by blending a base oil having a sulfur content of less than 0.03% by mass, a content of saturates of 90% by mass or above, a viscosity index of 80 or above and an absolute viscosity at 40 DEG C of 1 to 1000mPa s with (A) 1 to 20% by mass of a polymethacrylate-type viscosity index improver having a weight-average molecular weight of 10,000 to 50,000, (B) 0.005 to 5% by mass of an acid amide, (C) 0.005 to 5% by mass of (c-1) a specific hydrogenphosphate ester and / or (c-2) a specific hydrogenphosphite ester and (D) 0.005 to 5% by mass of at least one member selected from among polyhydric alcohol esters, alkanolamines, olefin sulfides, and thiocarbamates. The hydraulic oil composition exerts satisfactory and well-balanced properties essential to hydraulic oil which include energy saving, heat stability (sludge resistance), prevention of wear and scuffing, water shedding, and friction reduction in sliding parts.

Description

Technical field [0001] The present invention relates to a hydraulic working oil composition, and more specifically, to a hydraulic working oil composition, which has good energy saving properties, thermal stability (sludge resistance), abrasion resistance, and seizure resistance (anti-seize It is suitable for hydraulic machinery, work machinery, industrial machinery and so on. Background technique [0002] Hydraulic working oil is a power transmission fluid used in the power transmission, force control, buffering and other actions of hydraulic systems such as hydraulic equipment or devices, and can also serve as a lubrication function for sliding parts. [0003] There are metal-metal or metal-rubber (resin) sliding parts in pumps, control valves, hydraulic cylinders, etc. in the hydraulic circuit. The hydraulic working oil used in such a hydraulic circuit is required to have good friction characteristics such as wear resistance, seizure resistance, and friction reduction propertie...

AI Technical Summary

Problems solved by technology

[0011] However, even these hydraulic oils cannot be said to have sufficient friction characteristics such as sludge resistance (sludge suppression) and wear resistance.

[0012] Therefore, the present situation is that there is no hydraulic working oil that satisfies the required energy saving properties, thermal stability (sludge resistance), wear resistance, and seizure resistance (seizure resistance) in a balanced manner. , and further water separation properties and friction reduction of sliding parts, etc.

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