汽缸頭螺栓鎖緊技術之研究

The study of fastener technology for cylinder bolts

池勇達(Yung-Ta Chih)

指導教授 ： 黃國修

國立臺北科技大學/機電學院/車輛工程系所/碩士(2013年)

摘要

螺栓連接由於結構簡單、拆裝容易而且可以獲得很大的鎖緊力量，因此從微 小的機械零件到巨大的建築結構，長久以來被廣泛的應用於各種領域，而一般常 用的扭矩控制方法，由於受到螺栓座面與螺紋摩擦力不穩定的影響，鎖緊力產生 的偏差範圍較大，因此螺栓容易發生鬆弛和疲勞斷裂的失效情況。
本研究以汽車引擎之汽缸頭螺栓(Cylinder Head Bolt)為例，先以螺栓鎖緊時的應力與變形理論為基礎，藉由分析汽缸頭螺栓在鎖緊過程中鎖緊扭矩(Fastening Torque)與鎖緊力(Clamping Force)的關係，以找出影響鎖緊精度的關鍵因素，從實際生產過程常用的鎖緊控制方法中評估其優、缺點，將原有的螺栓鎖緊條件做當的修正，再以實驗方法驗證所提理論的有效性，使螺栓鎖緊的條件與精度控制 方法更適合應用於生產與維修作業的螺栓鎖緊技術。
實驗結果顯示，扭矩控制法因螺栓及汽缸體螺孔的製造誤差，鎖緊結果較為離散不易掌控，而扭矩角度控制法具有鎖緊力平均而穩定的優點，實驗也證明了 螺栓鎖緊規範，除了依據軸力需求與螺栓特性外，應從人體工學的角度進行設計，若螺栓鎖緊的起始扭矩及旋轉角度經過完整的測試發展而將螺栓鎖緊至塑性 域範圍，不但可以提高作業性，同時可以獲得精度高且穩定的鎖緊力。

實驗結果顯示，扭矩控制法因螺栓及汽缸體螺孔的製造誤差，鎖緊結果較為離散不易掌控，而扭矩角度控制法具有鎖緊力平均而穩定的優點，實驗也證明了 螺栓鎖緊規範，除了依據軸力需求與螺栓特性外，應從人體工學的角度進行設計，若螺栓鎖緊的起始扭矩及旋轉角度經過完整的測試發展而將螺栓鎖緊至塑性 域範圍，不但可以提高作業性，同時可以獲得精度高且穩定的鎖緊力。

關鍵字

汽缸頭螺栓 ； 鎖緊扭矩 ； 鎖緊力

並列摘要

As can be seen in micro mechanisms and colossal buildings, bolt joints are broadly used in various fields due to the simplicity of their design, easy application, and in the mean time provide sufficient clamping force. However, affected by the uncertainty of the bolt surface condition and the friction of coefficient on the thread, conventional torque control approaches often yield large clamping force variation and in consequence result in bolt loosening and fatigue failure.
In this research, we studied the cylinder head bolts under fastening condition based on the stress and distortion theory. Through the analysis of the correlation between the bolt fastening torque and clamping force, we discovered the crucial elements that determine the clamping accuracy. The known field techniques in bolt tightening are also evaluated and enhanced. Collaborated with experimental results, we provided improved bolt fastening condition in real field applications.
The result shows, with torque control approach, the clamping force may deviate due to the inherited bolt and cylinder block manufacturing error; however, the twist angle control approach gives more averaged clamping force. This result also verified that apart from the requirements defined in the norms, ergonomics must also be considered. With thorough development in the initial torque and twist angle studies, we can ensure the bolts be applied in the plastic deformation range and achieve precise and stable clamping force.

並列關鍵字

Cylinder Head Bolt ； Fastening Torque ； Clamping Force

參考文獻

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