目前,顶杆发动机已广泛应用在125ml摩托车上,它采用凸轮轴下置方式,性能稳定。与链条机相比,顶杆机简化了气门传动机构,其气门传动系统中的曲轴正时齿轮带动正时凸轮齿轮上的凸包推动下摇臂,将动力经顶杆传动至上摇臂,取代了链条传动,这种方式大大地节约了发动机成本。正时凸轮齿轮和曲轴正时齿轮作为正时动力传递机构,在顶杆机工作中起着重要的作用,但也是故障的高发区,下面对正时凸轮齿轮和曲轴正时齿轮的故 At present, the mandril engine has been widely used in 125ml motorcycle, which uses camshaft under way, stable performance. Compared with the chain machine, the ejector lever simplifies the valve drive mechanism. The crank timing gear in the valve drive system drives the convex arm on the timing cam gear to push the lower swing arm, and the power is transmitted to the upper swing arm via the top rod. The chain drive, this way greatly saves engine costs. As the timing power transmission mechanism, the timing cam gear and the crankshaft timing gear play an important role in the jack-up machine operation, but they are also the high-incidence areas for the failure. Therefore, timing cam gears and crankshaft timing gears are described below