【導讀】此論文主要講述的是注塑機的設計，它是成型塑件的一種重要工藝裝備。一定形狀和尺寸的塑件制品。此設計為為一盒體的外殼。根據(jù)其技術要求和使用要求，選擇塑料種類為ABS，再根據(jù)塑料的形狀和生產(chǎn)批量，選擇SZ-300/160注塑成型機。拔力大，運動平穩(wěn)。此模采用一模一腔，一次分型脫出塑件。型芯和型腔采用冷卻水槽結(jié)構的冷卻系統(tǒng)，采用氣塞排氣，可有限避免缺陷。在確定模具結(jié)構方案后，繪制模具裝配圖，并進行計。最后繪制模具非標準零件圖，經(jīng)全面審核后投產(chǎn)制造。

　　

【正文】 =1215N 許用轉(zhuǎn)速驗算 載荷系數(shù) f1 1r1CP =150001485 =，查圖 f11= r22CP =150001485 =，查圖 f11= 載荷分布系數(shù) f2 r1a1FF =0，查圖 f21= r2a2FF =0，查圖 f22= 許用轉(zhuǎn)速 N N1=f11 f21 N0= 9500 N1=9576r/min N2=f12 f22 N0= 9500 N2=9576r/min 因為非磁滾筒主軸的轉(zhuǎn)速遠小于 N1和 N2，故滿足要求。 結(jié)論：所選滾動軸承能滿足壽命、靜載荷和許用轉(zhuǎn)速的要求，且各項指標潛力都很大， 故所選軸承滿足要求。 第五章 其他設計問題 29 第 五 章 其他設計問題 總結(jié) 30 總結(jié) 通過本次設計，我更加清醒的意識到：要在以后的工作學習中，不斷地用理論來指導實踐，用實踐來證明理論，不斷的探索學習，積累 經(jīng)驗。 參考文獻 31 參考文獻 [1]蔡春源 . 機電液設計手冊 . 機械工業(yè)出版社 東北大學出版社 [2]江耕華，胡啟松等 . 機械傳動手冊 . 煤炭工業(yè)出版社 [3]劉向民，劉樹貽，陽邦平 . 新型 CSLY 陶瓷高梯度磁選機在陶瓷原料除鐵中的應用 . 非金屬礦， 1999 第 22 卷第 1 期 [4]邱宣懷，郭可謙等 . 機械設計 . 高等教育出版社 [5]王先逵 . 機械制造工藝學 . 機械工業(yè)出版社 [6]吳宗澤 . 機械設計使用手冊 . 化學工業(yè)出版社 [7]楊宏柯譯 . 磁選機磁力的測定方法 . 選礦機械， 1981 年第 1 期 [8]戈志明 . 干式磁選及磁選機的設計參數(shù) . 選礦機械， 1982 年第 2 期 32 致謝 感謝機械工程學院的所有老師在四年來對我學習和生活上的幫助，謹向所有老師表示衷心的感謝！ 33 Investigation of causes of fan shaft failure M. Ristivojevic, R. Mitrovic and T. Lazovic Belgrade University, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia Abstract Energy efficiency of thermal power plants depends on the vital plant elements’ reliability levels. In order to preserve high level of energy efficiency, the vital elements’ operational capabil ity is continually monitored via observing the working temperature, vibration and noise levels. Yet, however, in spite of this, and usually due to inadequate maintenance, inadequate assembly, errors in the design or manufacturing processes, or due to accidents, abrupt failures of the plant’s vital elements can occur. An example for this is the volumetric destruction of the fresh air fan shaft due to melting of the shaft at the shaft’s stationary support. In addition to shaft destruction, the fan bearing and wheel blades have undergone destruction as well. This breakdown has occurred in the course of continual monitoring of the bearing service temperature and vibrations levels. Former studies, aimed at determining the breakdown causes, were based on the detailed examination of the damaged 34 elements’ materials and detailed analysis of the bearing setting arrangement. Considering the fact that the shaft stationary support was realized by means of a doublepressed joint, a thorough analysis has been made in this paper of the pressed joint operational capability in the boundary service conditions, in order to determine the extent to which the pressed joint participated in the breakdown. Keywords: Fan。 Shaft。 Ball bearing。 Pressed joint。 Temperature Article Outline 1. Introduction 2. Setting arrangement analysis in fixed shaft support 3. Bearing setting arrangement breakdown condition description 4. Doublepressed joint analysis vs. bearing setting operational capability 5. Conclusion References 1. Introduction Fresh air fan feeds fresh air into the thermal power plant boiler. The fan uses a highvoltage AC electric motor as the driving machine, to which it is connected by way of a flexible coupling. The fan consists of a prewheel, 13blade working wheel and a shaft. Fan shaft is embedded on two doublerow, selfadjusting barrelshaped bearings of the 22340 176。CC/W33 type, with steel 35 cages, fitted on four cast concrete foundations, made especially for this purpose. The shaft’s technical characteristics are presented in Fig. 1. Fig. 1. Fan shaft Bearings rotation operational frequencies at the shaft supports, placed in separate housings, are close to boundary values (operational frequency is 740 min?1, and the boundary one is 850 min?1, for the permanent greaselubrication solution). In order to pensate for errors in the bearing setting arrangement and in order to ensure the shaft’s axial movement due to thermal deformations, the outer bearing is axially movable and fitted next to the electric motor, while the inner bearing is axially immovable. In service conditions, proper fan operation is ensured by continual monitoring of the electric motor service temperature, as the driving machine, and of both bearings on the fan shaft. Due to high operating temperatures, the plant ponents’ cooling has been provided electric motor is air cooled, while the initial structural solution of water cooling was replaced by air cooling. Yet, however, in spite of the continual monitoring of the fresh air 36 fan assembly’s vital elements’ operational capability, a major breakdown occurred, . the volumetric shaft destruction. In order to establish the causes of the breakdown, a thorough examination of the quality of materials was undertaken (microstructure examining and determining the shaft material’s chemical and mechanical properties) [1] and design solution for the bearing setting arrangement was analyzed [2]. Literature [1] provides images of the breakdown status of the fixed support’s bearing assembly setting arrangement. Literature [2] provides proposed optional solutions, aimed at improving the actual structural design of the shaft setting arrangement at the immovable support. Bearing in mind that the bearing setting arrangement in the shaft’s fixed support is realized by means of a doublepressed joint: shaft– bushing and bushing– bearing inner ring, this paper depicts a thorough analysis of the pressed joints’ operational capability in the extreme service and design conditions. Based on the performed analysis, the contribution of the pressed joints to the fan shaft breakdown in thermal plants has been recognized. 2. Setting arrangement analysis in fixed shaft support T