雷射紋理技術應用於活塞環表面之活塞摩擦特性探討

Investigation of the Friction Behavior of the Piston Ring Surface using Laser Surface Texturing

蕭亦夆(Hsiao I-Feng)

指導教授 ： 張金龍

國立屏東科技大學/工學院/車輛工程系所/碩士(2018年)

https://doi.org/10.6346/THE.NPUST.VE.014.2018.E07

摘要

本研究主要以光纖雷射為加工方式來對汽缸套件表面進行所謂的雷射表面紋理加工，此技術不僅可達成降低燃油損耗、減少汽缸套件間的摩擦與磨耗，並且在製程上無噪音與低粉塵而對環境影響較為友善而大量降低環境的污染。因此在實作方面將使用50W光纖雷射雕刻機建立技術本位層面，然後發展雷射表面紋理技術於車輛金屬材料上，對不鏽鋼410進行雷射表面紋理最佳參數搭配之探討。整個研究主要於實驗分析並考量各種加工參數，如刻痕幾何形狀(凹痕)、雷射功率、掃描頻率、掃描速度及曲面加工的控制等來探討雷射表面紋理結果。然後，再藉由自行簡易設計的摩擦試驗衝擊平台的運用，進行撞擊實驗，了解不同雕刻參數對摩擦特性之差異，之後再將不同參數進行搭配來找出最佳參數之組合，並應用田口方法分析找出何種參數對影響摩擦之特性最為顯著。從實驗結果得知，幾何紋理圖案的變化會影響摩擦效果，而比較了4種不同之紋理，其中的子彈紋理以其流體力學的流線造型特性，其滑行距離優於其他紋理，擁有較佳的潤滑效果，證實子彈型具有較低的摩擦阻力；以子彈造型為紋理基礎圖案時，隨著雕刻深度增加，撞擊力道越大，其機油潤滑作用越佳，可有效提升滑行距離並減少摩擦阻力，但持續增加深度則無明顯改善磨潤之效果；關於幾何紋理圖案大小對摩擦力的影響分析，實驗結果顯示改變紋理圖案的大小會小幅影響滑行距離，推論若試棒上雕刻的單個紋理圖案越小，整體紋理表面積擁有越多的接觸表面，使機油流動性增加，會小幅減少摩擦力，但在固定面積範圍的條件下，其接觸面積多寡並不會大幅影響摩擦力；若以子彈造型為紋理基礎圖案，隨著大幅度紋理面積的增加，活塞滑行距離增長，但若持續將紋理面積增加，其滑行距離反而下降，由實驗證明了過度的紋理面積比例無益於提升滑行距離；再對子彈形紋理圖案之間距進行實驗，結果顯示，適度調整紋理中圖案與圖案之間的軸向、徑向間距，皆能有效提升滑行距離，證實了適當的調整間距對減少摩擦阻力是一個重要因素；至於子彈紋理流線型方向的配置對於摩擦力的影響程度，實驗結果顯示紋理方向前後(←→)的紋理比其他之紋理方向來的好，其滑行距離最佳，由實驗證實了若採用方向前後擺放的紋理，有利於降低阻力；此外改變紋理位置亦會影響滑行距離，由實驗可知雕刻於前方位置提升滑行距離的效果比其他參數來得顯著，證實了改變雕刻紋理之位置亦會影響機油潤滑作用；最後使用一次一因子實驗法將參數進行搭配，從結果可以得知改善後的雕刻紋理參數組合，大幅提升了滑行距離。再將各個參數搭配組合應用田口方法並進行實驗後，可得出在選擇流線型子彈紋理加上紋理採前後方向的條件下，影響滑行距離之最明顯參數為幾何紋理之徑向間距。接著，從本研究可以得出若在活塞環之表面選擇子彈型紋理、適當的雕刻深度、適當的紋理圖案大小、適當之面積範圍、紋理擺放採前後方向及調整適當之間距並雕刻於前方位置將可有效降低活塞與汽缸之間的摩擦阻力。

關鍵字

光纖雷射 ； 雷射表面紋理 ； 汽缸套件 ； 摩擦特性

並列摘要

This research project is to investigate the laser surface texturing (LST) technique for cylinder-piston ring using fiber laser. This technique not only can achieve the object of reduction for fuel consumption, the friction and wear between cylinder and piston ring, but also can lower the environmental impact because of low noise and dust. In addition, the laser beam can provide flexibly a variety of patterns on work piece surface. Hence, this study will use the 50W fiber laser with scanning optic to build up the laser texturing technique basis, and apply this technique to investigate the optimal processing parameters for vehicle materials, such as stainless steel. The research project emphasizes the experimental analysis and the processing parameters include material, surface roughness, engraving shape (line or dimple), laser power, scanning frequency, scanning velocity, scanning direction, control of surface process. All of them will be investigated for the results of laser surface texturing. Then, the simply impact platform was designed to meet the test for friction behavior to conduct the impact test, and to understand the difference of the friction characteristics of different engraving parameters, and then to match the different parameters to find the best combination of parameters, and using the Taguchi method to find out which parameters having the most significant effect on the friction. The experimental results show that the change of the geometric texture pattern will affect the friction effect. After comparing the four textures, the bullet - shaped texture is superior to other textures and has better lubrication effect. When the bullet shape is used as the texture base pattern, as the engraving depth increasing with the impact force increasing, and the lubricating effect of the oil is better, which can effectively improve the sliding distance and reduce the frictional resistance, but the continuous increasing of the depth does not significantly improving the grinding effect. With regard to the influence of geometric texture pattern size on friction, the experimental results show that changing the size of the texture pattern will affect the sliding distance slightly. It is inferred that the smaller the single texture pattern engraved on the test bar, the more contact surface the overall texture surface has. Increased fluidity of the oil will reduce the friction slightly, but under the condition of a fixed area, the contact area will not greatly affect the friction. If the bullet shape is used as the texture base pattern, the sliding distance of the piston increases with the increase of the large-scale texture area. However, if the texture area is continuously increased, the sliding distance will decrease instead. It is proved by experiments that the excessive texture area ratio is not conducive to the lifting of the sliding distance. Experiments on the distance between the bullet-shaped texture patterns show that the axial and radial spacing between the pattern and the pattern in the texture can be appropriately adjusted to effectively improve the sliding distance. It is confirmed that proper adjustment of the spacing is an important factor in reducing frictional resistance. As for the degree of influence of the configuration of the streamline direction of the bullet texture on the frictional force, the experimental results show that the texture called front-back direction (←→) is better than the other direction textures, and the sliding distance is the best. It is confirmed by experiments that if the texture is placed front-back the direction, it is beneficial to reduce the resistance. In addition, changing the position of the texture will also affect the sliding distance. It is known from experiments that the effect of engraving in the front position to increase the sliding distance is more significant than other parameters. It is confirmed that changing the position of the engraving texture will also affect the lubrication of the oil. Finally, a one-factor experimental method is used to match the parameters. From the results, the improved engraving texture parameter combination can be known, and the sliding distance is greatly improved. After applying the parameters of the Taguchi method and combining the experiments, it can be concluded that under the condition of selecting the streamlined bullet texture plus the texture of the front-back direction mining, the most obvious parameter affecting the sliding distance is the radial spacing of the geometric texture. Then, from this study, it can be concluded that if the bullet-shaped texture is selected on the surface of the piston ring, the appropriate engraving depth, the appropriate texture pattern size, the appropriate area range, the front and rear of the texture placement, and the proper spacing and engraving in front The position will effectively reduce the frictional resistance between the piston and the cylinder.

並列關鍵字

fiber laser ； laser surface texturing (LST) ； cylinder-piston ring ； friction behavior

參考文獻

1. Yamakiri, H., Sasaki, S., Kurita, T., Kasashima, N.: “Effects of laser surface texturing on friction behavior of silicon nitride under lubrication with water,” Tribology International 44, p.579-584, 2011.

2. Grabon, W., Koszela, W., Pawlus, P., Ochwat, S.: “Improving tribological behavior of piston ring-cylinder liner friction pair by liner surface texturing,” Tribology International 61, p.102-108, 2013.

3. Vladescu, S. C., Olver, A. V., Pegg, I. G., Reddyhoff, T.: “The effects of surface texture in reciprocating contacts-An experimental study,” Tribology International 82, p.28-42, 2015.

4. Fu, Y. H., Lu, H. C., Hua, X. J., Yin, B. F., Tao, G. N.：“Theoretical analysis on lubrication and wear-resisting of honed cylinder liner,” Transactions of CSICE, Vol.24, No.6, p.559-564, 2006.

5. Hua, X., Sun, J., Zhang, P., Ge, H., Fu, Y., Jia, J., Yin, B.: “Research on discriminating partition laser surface micro-texturing technology of engine cylinder,” Tribology International 98, p.190-196, 2016.