Hydraulic gear machines (HGM) are a type of machines applied in the hydraulic drive and control systems where gears are the main unit both in terms of the design and operation principle. HGMs are utilized for converting mechanical energy into hydraulic energy or vice versa. In the former case, the machines are pumps, and in the latter, hydraulic motors._x000D_ The author has been dealing with HGMs for over 40 years, first individually, and for the last several years, as a mem...
