This paper presents the kinematic model and offers a rigorous analysis and description of the kinematics of planar harmonic drives. In order to reflect the fundamental kinematic principle of harmonic drives, the flexspline of a harmonic drive is assumed to be a ring without a cup. A tooth on the flexspline is a rigid body, and the motion of the tooth is fully governed by the wave generator and the nominal transmission ratio of the harmonic drive. The proposed model depicts the flexspline tooth and the wave generator as a cam-follower mechanism, with the follower executing a combined translating and oscillating motion. With the rigid tooth motion obtained, the conjugate condition between the flexspline and the circular spline is determined, from which the conjugate tooth profile can be derived. In this paper, the motion is governed by geometry, and the flexibility of the flexspline only serves as a spring to maintain the contact between the cam and the follower. For any wave generator and any transmission ratio, the explicit expression of the conjugate condition is presented. For a given circular or flexspline tooth profile, the exact conjugate tooth profile can be obtained. The phenomenon of twice engagement is discussed for the first time.
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e-mail: donghm@dlut.edu.cn
e-mail: kting@tntech.edu
e-mail: dlunwang@dlut.edu.cn
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January 2011
Research Papers
Kinematic Fundamentals of Planar Harmonic Drives
Huimin Dong,
Huimin Dong
Associate Professor
School of Mechanical Engineering,
e-mail: donghm@dlut.edu.cn
Dalian University of Technology
, Dalian 116024, P.R. China
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Kwun-Lon Ting,
Kwun-Lon Ting
Professor
Center for Manufacturing Research,
e-mail: kting@tntech.edu
Tennessee Technological University
, Cookeville, TN 38505
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Delun Wang
Delun Wang
Professor
School of Mechanical Engineering,
e-mail: dlunwang@dlut.edu.cn
Dalian University of Technology
, Dalian 116024, P.R. China
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Huimin Dong
Associate Professor
School of Mechanical Engineering,
Dalian University of Technology
, Dalian 116024, P.R. Chinae-mail: donghm@dlut.edu.cn
Kwun-Lon Ting
Professor
Center for Manufacturing Research,
Tennessee Technological University
, Cookeville, TN 38505e-mail: kting@tntech.edu
Delun Wang
Professor
School of Mechanical Engineering,
Dalian University of Technology
, Dalian 116024, P.R. Chinae-mail: dlunwang@dlut.edu.cn
J. Mech. Des. Jan 2011, 133(1): 011007 (8 pages)
Published Online: January 6, 2011
Article history
Received:
November 3, 2009
Revised:
October 22, 2010
Online:
January 6, 2011
Published:
January 6, 2011
Citation
Dong, H., Ting, K., and Wang, D. (January 6, 2011). "Kinematic Fundamentals of Planar Harmonic Drives." ASME. J. Mech. Des. January 2011; 133(1): 011007. https://doi.org/10.1115/1.4003140
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