Elements of machine design
Dexter Simpson Kimball
Paperback
(RareBooksClub.com, May 14, 2012)
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ...That portion of the rotating member which engages with the bearing is known as a journal. Journals are necessarily circular in all cross-sections, but their profile may be cylindrical, conical, spherical, or even more complex in form, as in the case of thrust bearings. (See Art. 105.) One or more of the following considerations affect the design of the bearing proper:--(a) Rigidity, in order that the alignment may not be seriously affected by deflection. (b) Strength, to resist rupture under the greatest loads. (c) Adjustment, to compensate for wear. (d) Formation and maintenance of an oil film. (e) Automatic adjustment, to insure alignment. (a and b). The inside diameter, or bore of the bearing, and also its length are fixed by the dimensions of the journal which engages with it; and the required strength and rigidity may be secured by a proper distribution of metal in accordance with the general principles discussed in Chapter III, and which apply to all forms of bearings, as far as strength and stiffness are concerned. Usually the question of strength does not enter into the design of the main part of the bearing. If, however, the cap A, Fig. 80, should be called upon to carry the load, as is often the case, its dimensions should, in general, be checked for strength, and its design should be such that stiffness is secured. The exact distribution of the pressure over a bearing is not known; but the assumption that the cap is a beam loaded at the centre and of a length equal to the distance between the cap bolts will give dimensions on the safe side for strength and deflection. The greatest bending moment and deflection for such beams are given in Case IX, Table 1. It is impossible to adjust the cap bolts so as to be sure that the load is uniformly distrib...