通用小型汽油机平衡计算与振动激振力分析

摘要

通用小型汽油机的振动大小对整机可靠性及噪声有一定的影响.笔者以168F汽油机为研究样机,分析了通用小型汽油机曲柄连杆机构和气缸布置的结构设计特点,对往复惯性力采用过量平衡法的不同曲轴过量平衡量及对整机振动的激振力进行了计算,分析了气缸斜置角度、曲轴过量平衡量和曲轴平衡块的尺寸公差对汽油机的激振力大小的影响,得出小型汽油机的最优平衡量及减小振动激振力变化的方法与措施,控制曲轴平衡块的制造精度能有效地减少批量生产中汽油机的振动变化.%The vibration of a utility small gasoline engine affects its reliability and noise level. Taking 168F gasoline engine as a sample, the design characteristics of crank connecting link and cylinder laying are analyzed , various over-balancing counterweights applied on reciprocating inertia force and the exciting force of engine vibration are calculated. The influences of tilting angle of cylinder, over-balancing counterweight, and the size tolerance of counterweight on the exciting force for gasoline engine are analyzed. The optimal counterweight for small gasoline engine and the measurements of reducing the variety of vibration exciting force are put forward. Production precision control of crankshaft counterweight can reduce the variety of vibration of gasoline engines of volume production.