外文翻譯---機械零件的強度-資料下載頁
2025-05-12 09:25本頁面
【導讀】承受的應力要大得多，以確保安全與可靠性。要保證機械零件在使用過程中不。力與強度聯(lián)系起來，以確保其安全。這些試驗應該采用與所設(shè)計的零件有著相同的熱處理，載荷完全相同的情況下進行。該進行彎曲載荷的試驗。這些種類的試驗可以提供非常有用和精確的數(shù)據(jù)?？梢愿嬖V工程師應該使用的安全系數(shù)和對于給定使用壽命時的可靠性。夠大的產(chǎn)量，則在設(shè)計前收集這樣廣泛的數(shù)據(jù)所花費的費用是值得的。具有較高的可靠性。在設(shè)計時安排一個完善的試驗程序會被認為是合理的。成很快地完成設(shè)計，以至于沒有足夠的時間進行試驗。需要采用分析的方法來弄清楚不能令人滿意的原因和應該如何進行改進。我們將主要對后三種類型進行討論。這就是說，設(shè)計人員通常只能利用。身的延伸性而具有很好的承受超載荷的能力。軸安裝在軸承中，通過齒輪、皮帶輪、凸輪和離合器等零件傳遞動力。止支承軸承受力過大。彎曲變形不應該超過英寸?？紤]疲勞現(xiàn)象的安全系數(shù)。減少到最低程度。
【正文】 s above 5 in. shaft are forged and machined to size. Plastic shafts are widely used for light load applications. One advantage of using plastic is safety in electrical applications, since plastic is a poor conductor of electricity. Components such as gear and pulleys are mounted on shafts by means of key. The design of the key and the corresponding keyway in the shaft must be properly evaluated. For example, stress concentrations occur in shafts due to keyways, and the material removed to form the keyway further weakens the shaft. If shafts are run at critical speeds, severe vibrations can occur which can seriously damage a machine. It is important to know the magnitude of these difference between the operating speed and the critical speed should be at least 20 percent. Another important aspect of shaft design is the method of directly conneoting one shaft to another. This is acplished by devices such as rigid and flexible couplings. A coupling is a device for connecting the ends of adjacent shafts. In machine construction, couplings are used to effect a semipermanent connection between adjacent rotating shafts. The connection is permanent in the sense that it is not meant to be broken during the useful life of the machine, but it can be broken and 外文資料 9 restored in an emergency or when worn parts are replaced. There are several types of shaft couplings, their characteristics depend on the purpose for which they are used. If an exceptionally long shaft is required in a manufacturing plant or a propeller shaft on a ship, it is made in sections that are coupled together with rigid couplings. A mon type of rigid coupling consists of two mating radial flanges (disks) that are attached by keydriven hubs to the ends of adjacent shaft sections and bolted together through the flanges to form a rigid connection. Alignment of the connected shafts is usually effected by means of a rabbet joint on the face of the flanges. Inconnecting shafts belonging to separate devices (such as an electric motor and a gearbox), precise aligning of the shafts is difficult and a flexible coupling is used. This coupling connects the shafts in such a way as to minimize the harmful effects of shaft misalignment. Flexible couplings also permit the shafts to deflect under their separate systems of loads and to move freely (float) in the axial direction without interfering with one another. Flexible couplings can also serve to reduce the intensity of shock loads and vibrations transmitted from one shaft to another.
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