VEGETABLE OIL-BASED HYDRAULIC FLUID AND TRANSMISSION FLUID

摘要

The invention relates to using vegetable oil having a natural viscosity index (VI) of greater or equal to 200 as a pressure medium in hydraulic systems and as a transmission fluid. The vegetable oil has a portion of monounsaturated fatty acids of at least 80%, a portion of double unsaturated fatty acids of 1-10% at maximum, and a portion of triple unsaturated fatty acids of less than 1%, preferably less than 0.1%. Part of the vegetable oil can be used in the form of an unsaturated ester of the vegetable oil. The vegetable oil can also contain an additive in a portion of 2-5% by weight selected from anti-oxidants, copper deactivators, anti-corrosion agents, wear protection agents and anti-foaming agents. The shear stability of the vegetable oil used according to the invention equals 0.7% or less, measured over 20 hours of use.