Tham khảo tài liệu 'sổ tay tiêu chuẩn thiết kế máy p47', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 40 CAM MECHANISMS Andrzej A. Ol dzki Warsaw Technical University Poland SUMMARY I CAM MECHANISM TYPES CHARACTERISTICS AND MOTIONS I BASIC CAM MOTIONS LAYOUT AND DESIGN MANUFACTURING CONSIDERATIONS FORCE AND TORQUE ANALYSIS CONTACT STRESS AND WEAR PROGRAMMING REFERENCES SUMMARY This chapter addresses the design of cam systems in which flexibility is not a consideration. Flexible high-speed cam systems are too involved for handbook presentation. Therefore only two generic families of motion trigonometric and polynomial are discussed. This covers most of the practical problems. The rules concerning the reciprocating motion of a follower can be adapted to angular motion as well as to three-dimensional cams. Some material concerns circular-arc cams which are still used in some fine mechanisms. In Sec. the equations necessary in establishing basic parameters of the cam are given and the important problem of accuracy is discussed. Force and torque analysis return springs and contact stresses are briefly presented in Secs. and respectively. The chapter closes with the logic associated with cam design to assist in creating a computer-aided cam design program. CAM MECHANISM TYPES CHARACTERISTICS AND MOTIONS Cam-and-follower mechanisms as linkages can be divided into two basic groups 1. Planar cam mechanisms 2. Spatial cam mechanisms In a planar cam mechanism all the points of the moving links describe paths in parallel planes. In a spatial mechanism that requirement is not fulfilled. The design of mechanisms in the two groups has much in common. Thus the fundamentals of planar cam mechanism design can be easily applied to spatial cam mechanisms which 1 Prepared while the author was Visiting Professor of Mechanical Engineering Iowa State University Ames Iowa. STANDARD HANDBOOK OF MACHINE DESIGN a FIGURE a Planar cam mechanism of the internal-combustion-engine .
