[Objectives]In order to improve the tractor ride comfort and performance in our country,tractor front axle hydro-pneumatic spring was studied. [Methods]Taking the CF700 tractor as the research object,the vibration differential equation of tractor front axle suspension system was established,and the three degrees of freedom vibration model of front axle suspension tractor were built up.Based on the requirement of CF700 tractor front axle suspension parameter,hydro-pneumatic spring with controllable stiffness...