HMT (The hydraulic and mechanical transmission) is a new type stepless transmission. Its construction and primary principle are analysed. The application on large crawler tractors and bulldozers have been introduced.

• 液压机械传动(HMT)是一种新型的无级变速装置。主要介绍了它的组成结构、基本原理以及国内外在大功率履带拖拉机、推土机上的应用与分析。