【摘要】 采用凸轮和杠杆机构作为控制装置,以完全机械—液压方式,不需电的转换,研究设计了一种液压起重机角反馈自动调压系统。系统利用凸轮机构作为吊臂角位移信号输入和转换的环节,将输入量吊臂变幅角度α转换为与之相对应的系统压力p1所要求的先导式溢流阀导阀调压弹簧的预压缩量Xt2。采用杠杆机构作为比例环节以实现线位移的放大以及相互作用力的匹配,从而控制Xt2以实现吊机系统压力p1随吊臂变幅角度α的自动连续调节。系统的核心部分是一个专用先导式溢流阀,它起到根据控制信号调节系统压力p1的作用,实现机—液的转换。先导式溢流阀采用差压式结构,提高了其在低压范围的调压稳定性,并可获得较好的启闭性能,从而实现了用1根调压弹簧在吊机工作压力3~17 MPa(本例)范围内进行连续调压。液压起重机角反馈自动调压系统设计的关键在于通过理论计算预先确定先导式溢流阀调定压力p1与先导阀调压弹簧预压缩量Xt2的函数关系,作为控制系统设计的基础。实验结果表明,采用液压起重机角反馈自动调压系统可以较好地解决液压起重机施工过程可能出现的过载问题。更多还原

【Abstract】 An angle feedback pressure self-regulating system was studied and designed in a complete mechanical and hydraulic way without electric converting.A cam mechanism was used to input and convert the signal of the crane-arm’s angle changing.The input signal,i.e.the radius-changing angle α of the crane arm is converted into the length reduction X_t2 of the pilot relief valve’s pressure regulating spring by the cam mechanism,which corresponds with the pressure p₁ of the crane’s hydraulic system.The lever is designed as a proportional and amplifying part in order to coordinate the transmitted force and control the length reduction X_t2 and then accordingly control the pressure p₁ continuously.The pilot valve’s type is in the difference-pressure form.It can improve the pressure regulating stability in the lower pressure range and realize the function of regulating the pressure of the hydraulic system at the range from 3 MPa to 17 MPa only with the same one spring of the pilot valve.To get the analytic function formula about the two variables,i.e.the regulated pressure p₁ and the length reduction X_t2 in advance is the most important step in design.The results show that the angle feedback pressure self-regulating system for hydraulic crane can effectively solve the problem of angle feedback pressur self-regulating of hydraulic cranes.更多还原