Thegear motorhas a rotarymotionby usingan inverseto that ofthehydraulicpumptechnique.Gearmotorsare as fast asthoseaxial pistonand are widely usedbecause theyare cheap.
Theorbitrolenginesrun onoilandare mainly used forassisteddirectionscars, othervehicles andalsorecentsystemshydraulichitchesmoderntractors.