文档介绍：Available online at hanism
and
Machine Theory
Mechanism and Machine Theory 43 (2008) 909–917
ate/mechmt
On the kinematics and ics of mechanical seals, rotors,
and wobbling bodies
Itzhak Green *
ia Institute of Technology, . Woodruff School of Mechanical Engineering, Atlanta, GA 30332-0405, United States
Received 5 January 2007; received in revised form 12 June 2007; accepted 12 June 2007
Available online 6 August 2007
Abstract
Mechanical seals, rotors, and wobbling bodies whirl about a point and are characterized by a kinematical constraint
that prevents them from having integral motion with respect to the axis of whirl. A valid kinematical model is a prerequi-
site to subsequent dynamic analyses. Three previous works have suggested distinctly different kinematical models for the
same problem. The analysis herein presents yet another kinematical model that preserves (actually enforces) the proper
kinematical constraint. Interestingly, it is found that although no integral rotation is allowed about the axis of whirl,
the wobbling body possesses a sustained nonzero angular velocity about that axis. The derivation is done for any finite
nutation angle and only final results are being degenerated to small tilt angles. The e reaffirms the results of a pre-
vious work. For this time-invariant problem the notion of virtual velocity and virtual power emerges,