【正文】 又充實的畢業(yè)設(shè)計中度過，讓我受益匪淺。 畢業(yè)設(shè)計讓我對以前的知識又有了一次完整而系統(tǒng)的復(fù)習(xí)，并且通過閱讀一些畢業(yè)設(shè)計相關(guān)書籍，也讓我學(xué)習(xí)到了很多有用的知識，對現(xiàn)在的機械知識進行了補充，同時也了解了很多將來工作中需要的知識，學(xué)會了如何正確的去使用一些資料、技術(shù)手冊，問我以后在工作中進步打下了結(jié)實的基礎(chǔ)。 在畢業(yè)設(shè)計中隊機械制造的工藝工序設(shè)計，夾具設(shè)計、 CAD制圖進行了一次復(fù)習(xí)、實踐。 在這次畢業(yè)設(shè)計中我也能明顯的感覺出自己的不足，設(shè)計中還存在這很多的錯誤和缺陷，在這里懇請各位老師、同學(xué)指導(dǎo)改正。 34 致謝 為期兩個半月的畢業(yè)設(shè)計不知不覺已經(jīng)到了結(jié)束的時候，這次畢業(yè)設(shè)計是我在大學(xué)之中所接觸到的最難，也是最復(fù)雜的一次設(shè)計，然而還能順利完成，這是各位老師的功勞。在這里謹向大學(xué)四年里辛勤教導(dǎo)我的老師致以崇高的謝意！特別是要感謝彭銳濤老師對我無微不至的關(guān)懷和教導(dǎo)。 本文所研究的內(nèi)容是在彭老師的細心指導(dǎo)下完成，也正是彭老師以其豐富的實踐經(jīng)驗、深厚的專業(yè)知識為本課題的設(shè)計提供了許多有效的指導(dǎo)和理論依據(jù)，才能使本課題得以圓滿完成和論文的順利結(jié)束，更重要的是彭老師待人的和藹、工作治學(xué)的嚴謹讓我受益匪淺，不僅讓我在學(xué)習(xí)上進步，也 讓我學(xué)會了應(yīng)該用怎樣的態(tài)度對待工作，在此再次向彭老師表示深深的謝意。 同時還要感謝和我一起進行畢業(yè)設(shè)計工作的同學(xué)，在畢業(yè)設(shè)計工程中大家相互幫助、支持。這幾個月中為我解決了很多問題，并督促我讓我不至于放松。 感謝那些平時給予我指導(dǎo)和幫助的老師、同學(xué)。 謝謝！ 35 附錄清單 a 中心距 α 折合系數(shù) b 齒輪寬度 aρ 頂圓齒形曲徑 d 軸的直徑 0a 齒輪嚙合角 h 軸肩高度 aε 斷面重合度 I 傳動比 ag 端面嚙合長度 K 載荷系數(shù) ah * 齒頂高系數(shù) L 軸的長度 C* 齒輪頂隙系數(shù) m 齒輪模數(shù) tζ 扭轉(zhuǎn)切應(yīng)力 n 軸的轉(zhuǎn)速 ψ 嚙合損失系數(shù) on 行星輪數(shù)目 Na 盈利循環(huán)系數(shù) t 總運轉(zhuǎn)時間 T 轉(zhuǎn)矩 W 軸的抗彎截面系數(shù) X 齒輪變位系數(shù) P 軸傳遞的功率 Z 齒數(shù) η 傳動功率 d 齒輪分度圓直徑 gd 齒輪基圓直徑 d’ 齒輪節(jié)圓直徑 gd 齒輪基圓直徑 d’ 齒輪節(jié)圓直徑 ad 齒頂圓直徑 fd 齒根圓直徑 1δ 孔距相對偏差 36 文獻翻譯 Blade pitch mechanism As a rule, large wind turbines have rotors equipped with blade pitch control. The mechanism required for this must basically fulfil two tasks. The primary task is to adjust the blade pitch angle for controlling the power and speed of the rotor. A pitching range of around 20 to 25 degrees is enough for this purpose. But apart from this main function, there is a second task which has considerable influence on the design of t he blade pitch mechanism. To brake the rotor aerodynamically, it must be possible to pitch the rotor blade to the feathered position. This increases the pitching range to approximately 90. The implementation of the blade pitch mechanics offers the designer possibilities for design creativity scarcely rivaled by any other system. The model implemented are accordingly variety can be attained if the “blade pitch mechanism ”system is broken down into its main ponents. Rotor blade bearing The prerequisite for implementing blade pitching is the ability to turn the rotor blades around their longitudinal axis. Even though the necessary angle of rotation and the rotating speeds are relatively small, the rotor blade are almost exclusively supported by roller bearing at the blade root. In some earlier turbines,only the outer blade area was adjusted(Chapt,531, .18).In this case the bearing and the blade pitch drive must be relocated into the outer blade area. This poses additional design problems with respect to spatial conditions and weight at an awkward place in the outer blade section. Blade pitching driving The main distinguishing feature of blade pitching systems is the type of drive. Hydraulic drives are still in the majority in older wind turbines but an alternative are electrical motors and these are increasingly found in more recent turbines. The reasons are the extended control possibility and precision of the newer electronically controlled pitching motors, and the avoidance of the leakage problem experienced with hydraulic units. Actuator elements The design of the actuating elements depends on the selected drive units, on the one hand, and, on the other hand, on the arrangement of the blade pitch drive in the space of the nacelle or of the rotor hub. Hydraulic actuating elements at the same time. If pitching drives other than direct actuators are used, it bees necessary to effect the movement on the rotor blades via mechanical actuating elements. This job can be handled by pitching shafts, toothed gearing or any conceivable linkage mechanism. Power supply The blade pitching drive must be supplied with power. In most cases, the power supply system of the blade pitching system is housed in a fixed position within the nacelle. In the case of electrical systems, installation of the blade pitch motor or actuator in the rotating rotor hub require the electric current to be transmitted into the hub via a slipring, whilst hydraulic systems require a rotary leadthrough of the supply line. If, apart from the power supply, the pitching system is also installed in a fixed position in the nacelle, the connection to the rotating hub can be implemented with mechanical parts. This can be done by means 37 of connecting rods or rotary shafts passing through a hollow rotor shaft. These designs have the advantage that all parts of the blade pitching system requiring frequent maintenance are housed in the nacelle. Emergency blade pitching system Wind turbines with blade pitch control can generally only brake the rotor by pitching the rotor blade to the feathered position. If the rotor lose all its load suddenly, say when the generator loses synchronization, pitching the rotor blades to the feathered position must be done rapidly to prevent rotor runway. Reliable operation of the blade pitch mechanism. Thus, most turbines have an additional emergency drive system for blade pitching which operates more or less independently of the normal blade pitching system. Enumerating the main ponents of the blade pitch mechanism show that this is a plex system. It involves both the rotor and the mechanical drive train. The blade pitch system is therefore one of the systemdetermining