故障的分析、尺寸的決定以及凸輪的分析和應(yīng)用
前言介紹：
作為一名設(shè)計工程師有必要知道零件如何發(fā)生和為什么會發(fā)生故障，以便通過進行最低限度的維修以保證機器的可靠性。有時一次零件的故障或者失效可能是很嚴(yán)重的一件事情，比如，當(dāng)一輛汽車正在高速行駛的時候，突然汽車的輪胎發(fā)生爆炸等。另一方面，一個零件發(fā)生故障也可能只是一件微不足道的小事，只是給你造成了一點小麻煩。一個例子是在一個汽車?yán)鋮s系統(tǒng)里的暖氣裝置軟管的松動。后者發(fā)生的這次故障造成的結(jié)果通常只不過是一些暖氣裝置里冷卻劑的損失，是一種很容易被發(fā)現(xiàn)并且被改正的情況。
能夠被零件進行吸收的載荷是相當(dāng)重要的。一般說來，與靜載重相比較，有兩個相反方向的動載荷將會引起更大的問題，因此，疲勞強度必須被考慮。另一個關(guān)鍵是材料是可延展性的還是脆性的。例如，脆的材料被認(rèn)為在存在疲勞的地方是不能夠被使用的。

Applications Of Cams
INTRODUCTION
It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．
The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved．