星型空压机曲柄连杆机构动力学特性分析

Dynamic characteristic analysis of crank connecting rod mechanism in star-type air compressor

[目的]相对于其他类型的空压机,往复式空压机能够获取更高压力的压缩空气,因而曲柄连杆机构的受力较大。[方法]对比分析3种结构形式的星型往复式空压机惯性力和力矩的特点,得出该型空压机对惯性力有良好的自平衡能力,能在一定程度上减小惯性力矩。建立曲柄连杆机构虚拟样机,将推导的活塞受力构造SPLINE曲线加载到活塞质心,分别将曲轴和连杆柔性化,并将基于IMPACT函数的接触碰撞力模型嵌入到ADAMS虚拟样机中。[结果]动力学仿真结果表明:该型空压机能够自平衡二阶惯性力,曲轴相对于连杆更趋近于柔性体,间隙运动副的存在会抑制某些频率点的振动,但会大大拓宽激振频带。[结论]该分析结果可为空压机的设计提供参考。

[Objectives]Compared with other types of air compressor,reciprocating compressors can obtain compressed air with a higher pressure,exerting more stress on the crank connecting rod mechanism.[Methods]This paper analyzes the inertia force and torque characteristics of the three structural forms of the star-type reciprocating air compressor.It then concludes that the air compressor has a good self-balance ability of inertial force while also reducing inertial torque to a certain extent at the same time.A virtual prototype of a crank connecting rod mechanism is built.The derivation of the force on the piston is acquired in order to construct a SPLINE curve,which is loaded on the centroid of the piston.With a flexible crankshaft,the contact force model of the IMPACT function is added between the crank pin and connecting rod.[Results]The dynamic simulation results show that the air compressor can self-balance second-order inertial force.Clearance will decrease the vibration of the air compressor to a certain extent,but will greatly broaden the excitation frequency band.[Conclusions]The findings of this paper can provide valuable references for the design of air compressors.