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Sổ tay tiêu chuẩn thiết kế máy P42

Tham khảo tài liệu 'sổ tay tiêu chuẩn thiết kế máy p42', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 35 HELICAL GEARS Raymond J. Drago P.E. Senior Engineer Advanced Power Train Technology Boeing Vertol Company Philadelphia Pennsylvania 35.1 INTRODUCTION 35.1 35.2 TYPES 35.2 35.3 ADVANTAGES 35.2 35.4 GEOMETRY 35.5 35.5 LOAD RATING 35.8 REFERENCES 35.57 The following is quoted from the Foreword of Ref. 35.1 This AGMA Standard and related publications are based on typical or average data conditions or applications. The standards are subject to continual improvement revision or withdrawal as dictated by increased experience. Any person who refers to AGMA technical publications should be sure that he has the latest information available from the Association on the subject matter. Tables or other self-supporting sections may be quoted or extracted in their entirety. Credit line should read Extracted from ANSI AGMA 2001-B88 Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth with the permission of the publisher American Gear Manufacturers Association 1500 King Street Alexandria Virginia 22314. This reference is cited because numerous American Gear Manufacturer s Association AGMA tables and figures are used in this chapter. In each case the appropriate publication is noted in a footnote or figure caption. 35.1 INTRODUCTION Helical gearing in which the teeth are cut at an angle with respect to the axis of rotation is a later development than spur gearing and has the advantage that the action is smoother and tends to be quieter. In addition the load transmitted may be somewhat larger or the life of the gears may be greater for the same loading than with an equivalent pair of spur gears. Helical gears produce an end thrust along the axis of the shafts in addition to the separating and tangential driving loads of spur gears. Where suitable means can be provided to take this thrust such as thrust collars or ball or tapered-roller bearings it is no great disadvantage. Conceptually helical gears may be thought of as stepped spur .