无换向架链条抽油机轨迹链条受力分析

Force analysis of path chain on chain drive pumping unit without reverse rack

无换向架链条抽油机的链条承受的总拉力为悬点载荷与平衡重的差值加连杆对链条的水平分力在链条上形成的附加拉力之和，受力状况优于普通链条抽油机，且能得到控制。链条承受的附加拉力与连杆长度和偏心距有关，当两者取适当值时，通过调节装置可使链条上既不会产生过大的附加拉力，又可使链条始终处于张紧状态，避免反向冲击和脱链，减少抽油机工作时的振动和噪音，提高工作寿命。经现场试用，效果良好。

The force conditions of the chain on a chain drive pumping unit without reverse rack are much more favorable than that on conventional chain drive pumping units,and can be well controlled.The additional pulling force on the chain has relation to the length and the eccentricity of the pitman.By selecting proper pitman length and eccentricity and by means of an adjusting device,excessive additional pulling force on the chain can be avoided,while necessary tension of the chain can be assured throughout the operation to avoid reverse impact and chain slip.