求翻译：液压传动的基本原理是在密闭的容器内，利用有压力的油液作为工作介质来实现能量转换和传递动力的。其中的液体称为工作介质，一般为矿物油，它的作用和机械传动中的皮带、链条和齿轮等传动元件相类似。是什么意思？

Fundamentals of hydraulic drive is in a closed container, using oil as a working medium pressure to achieve energy conversion and transmission power. Liquids which are called medium, typically a mineral oil, its role and mechanical drive belt, chain and gear, and other components are similar.