| 摘要: | 螺旋傘齒輪因具有較高的接觸率、較高的齒面承載能力以及平順傳動性能，為常應用在具有軸交角的機械傳動元件。而使用粉末冶金模造法進行加工的螺旋傘齒輪，則可以具有大量生產、低成本的優點，符合各種中、小型傳動設備的使用需求，如電動、園藝等傳動齒輪箱。
本研究之目的，係針對應用粉末冶金製造方式的螺旋傘齒輪，提出一套完整的受載齒面分析方法，以能分析所設計的修整型齒輪，以了解組裝誤差以及偏心誤差對於接觸過程以及傳動誤差的影響，以及齒輪對在嚙合過程的負載特性。
為了避免螺旋傘齒輪脫模時產生干涉現象，在本論文中螺旋傘齒輪齒面使用球面漸開線齒廓沿軸線等角度旋轉方式產生，並對小齒輪齒面進行雙隆起修整，以改善接觸狀況。在文中亦發展出螺旋傘齒輪脫模的分析模式，以確保是否可以脫模，並能決定所對應合適的脫模旋轉角度。
本論文根據球面漸開線之法線幾何特性發展出無負載狀態下的齒面接觸分析模型，可簡化齒面嚙合接觸點位置之求解。此方法同樣適用於具組裝誤差與偏心誤差狀況下的螺旋傘齒輪對之接觸特性，即接觸點在齒面位置之變化以及傳動誤差。
同時發展齒輪對嚙合之受載齒面接觸分析模式，係使用影響係數法為基礎，將齒面接觸、齒面彎曲、軸彎曲以及軸扭轉等變形影響同時納入，以得到嚙合齒對受載應力分佈、受載傳動誤差以及負載分配結果。
本論文中設計出一組螺旋傘齒輪對，其設計符合業者之設計要求，供割草機使用，並經分析確認可脫模。再以無負載齒面接觸分析，探討各主要組裝誤差的影響，分析結果發現偏位誤差最為敏感，其次為小齒輪軸向誤差與大齒輪軸向誤差，而角度誤差對於接觸點幾乎不影響。此螺旋傘齒輪對之傳動誤差曲線近似拋物線，不同的組裝誤差對此影響不大；而齒輪偏心量的傳動誤差是由單一齒對之拋物線型傳動誤差曲線所組合成的類似正弦變化曲線，且整體振幅遠大於單一齒對拋物線曲線振幅。
使用本論文發展之受載齒面接觸分析模型分析所設計螺旋傘齒輪，結果發現組裝誤差量過大時，接觸開始以及結束位置仍會產生輕微邊緣應力接觸；而組裝誤差主要影響接觸齒對起點與終點的角度，對於受載傳動誤差曲線影響較低。同時在本論文中也探討因為使用懸臂樑支撐，螺旋傘齒輪在左、右齒面接觸狀況下的接觸斑差異，分析結果顯示在合適的修整下，齒輪左、右齒面的接觸特性差異可降到最小。
;Spiral bevel gears which have high contact ratio, high load capacity, and smooth transmission are usually used on augular transmission. the powder metallurgy modify spiral bevel gears , are cheap and can be mass-produced, suitalbe for small and medium sized equipment, like electrical tools and gardening tools.
The purpose of this study is designing powder metallurgy modify spiral bevel gear and building analysis method for it,so the influences of assembly errors, the influences eccentric errors and the load characteristics in contact process can be confirmed.
To avoid interference happen between gear and model, the spiral bevel gear is desgin by axis-rotating spherical involute. The pinion is modified to improve the contact stress. Also, developing the mold stripping anaylsis method can find the mold stripping angle.
The tooth contact anaylsis (TCA) of spiral spherical involute bevel gear, is based on characteristics of normal vectors, can simplify the solving procedure. This method can ues on the gear pair with assemble errors and eccentric errors, finds contact variety on tooth surface and transmission error.
The load tooth contact analysis (LTCA) is based on influnce coefficinet method, included tooth contact, tooth bending, shaft bending, and shaft twist, to determine tooth contact stree, load transmission error, and load sharing.
In this study, a spiral bevel gear pair is desgined by the requirement of cooperation vendor, and confirm it can strip. In addition, the gear pairs use TCA to find the influences of assembly errors. The result show the contact position of the tooth pair due to the offer errors caues is the most sensitive, the next is due to mounting distance of the gear and the pinion. The shaft angles error slightly affects the conatact position. The curve of transmission error is parabolic curve, even gear pairs have assembly errors. But the curve of transmission error of the tooth pair wiht eccentric error is similar to sine curve combined by parabolic curves. The amplitude of sine curve is greater than the amplitude single parabolic curve.
The LTCA result of gear pairs show that large assembly errors cause concentrated contact stress still occurs nearby the contcat begin position and the conatcat end position. The assembly errors sightly affect the LTE curve, and affect the contact begin angle and the contact end angle. Because of the gear pairs support by cantilever beam , the contact stress on right tooth side need to compare with left tooth side. The result show that the appropriate modify make the contact stress on both side almost same. |
