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Frontiers of Mechanical Engineering

Front Mech Eng    2012, Vol. 7 Issue (1) : 5-15     https://doi.org/10.1007/s11465-012-0310-y
RESEARCH ARTICLE |
On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate cam mechanism
Hui Ching FAN, Hong Sen YAN()
Department of Mechanical Engineering, Cheng Kung University, Tainan 70101, China
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Abstract

Without modifying the cam contour, a cam mechanism with a variable input speed trajectory offers an alternative solution to flexibly achieve kinematic and dynamic characteristics, and then decrease the follower’s residual vibration. Firstly, the speed trajectory of cam is derived by employing Bezier curve, and motion continuity conditions are investigated. Then the motion characteristics between the plate cam and its roller follower are derived. To analyze the residual vibration, a single degree of freedom dynamic model of the elastic cam-follower system is introduced. Based on the motion equation derived from the dynamic model, the residual vibration of the follower is yielded. The design procedure to improve the kinematic and dynamic motion characteristics is presented and two design examples with discussions are provided. Finally, the simulations of the kinematic and dynamic models by ADAMS are carried out and verified that the design models as well as the performances of the mechanism are feasible.

Keywords cam mechanism      variable input speed      kinematic design      dynamic design      optimal design     
Corresponding Authors: YAN Hong Sen,Email:hsyan@mail.ncku.edu.tw   
Issue Date: 05 March 2012
 Cite this article:   
Hui Ching FAN,Hong Sen YAN. On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate cam mechanism[J]. Front Mech Eng, 2012, 7(1): 5-15.
 URL:  
http://journal.hep.com.cn/fme/EN/10.1007/s11465-012-0310-y
http://journal.hep.com.cn/fme/EN/Y2012/V7/I1/5
Fig.1  Dynamic model of an elastic cam-follower system
Fig.2  Force analysis of the dynamic model
SectionCam rotate angleFollower stroke/mmStroke time/s
Rise□= 120°250.057
Dwell 1□= 60°00.029
Fall□= 120°-250.057
Dwell 2□= 60°00.029
Tab.1  Plate cam profile
ItemsSpecifications
Return spring ratio Kr2.79 N/mm
Equivalent spring ratio of the follower Kf1.553×106 N/mm
Equivalent mass of the follower m0118.8725 kg
Damping ratio ξ0.1
Tab.2  Dynamic model parameters
Fig.3  Motion characteristics (Example 1). (a) Cam; (b) follower and output mass
Fig.4  Residual vibration amplitude of the output mass (Example 1)
Fig.5  Motion Characteristics (Example 2). (a) Cam; (b) follower and output mass
Fig.6  Residual vibration amplitude of the output mass (Example 2)
Fig.7  Adams simulation
Fig.8  Simulation result of the cam motion characteristics (Example 2)
Fig.9  Simulation result of the follower motion characteristics (Example 2)
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