桑塔纳轿车采用的是顶置凸轮轴式液压挺杆 ,其结构及工作原理如图1所示 ,凸轮的驱动力通过液压挺杆直接传递给气门 ,使气门的开闭更及时。这种结构具有工作噪音小、不需检查与调整气门脚间隙等优点 ,工作可靠。但随着汽车行驶里程的增加 ,气门挺杆会因机械磨损或挺杆内腔进入空 Santana used overhead camshaft hydraulic tappet, its structure and working principle shown in Figure 1, the driving force of the cam through the hydraulic tappet directly to the valve, the valve opening and closing more timely. This structure has the advantages of low noise, no need to check and adjust the valve clearance, etc., work reliably. However, with the increase of car mileage, the valve tappet due to mechanical wear or tappet cavity into the empty