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Contributions to the elaboration and research on the kinematic planetary precessional transmissions

Author: Bodnariuc Ion
Degree:doctor of engineering
Speciality: 05.02.02 - Theory of machines and machine elements
Scientific adviser: Valeriu Dulgheru
doctor habilitat, professor, Technical University of Moldova
Institution: Technical University of Moldova
Scientific council: DH 31-05.02.02-27.03.08
Technical University of Moldova


The thesis was presented on the 12 March, 2010
Approved by NCAA on the 29 April, 2010


Adobe PDF document6.87 Mb / in romanian


The thesis comprises several compartments: an introduction, five parts, conclusions, references with 104 names and 8 annexes. The volume is 115 pages, including 109 figures and 10 tables. The main content of the thesis has been published in 17 scientific papers, including 6 papers written by one author, 4 papers in scientific journals and 4 patents.

It is necessary to carry out supplementary fundamental research in order to utilise on a large scale kinematical planetary precessional transmissions which are mechanical transmissions relatively complex in the kinematical aspect. This paper describes the results of theoretical and experimental research on the kinematical planetary precessional transmissions undertaken in the period 2000-2009. The performed analysis of the state-of-the-art in the field of planetary transmissions with multiple gearing, in general, and of the kinematical planetary precessional transmissions, in particular, demonstrated the need to study the power losses, to analyse the factors which contribute to these power losses, to elaborate the constructive-technological procedures for their decreasing.

The results of complex research (both analytical and CAE models) on the influence of the basic precessional gearing geometrical parameters (Z1, Z2, δ, θ, β) on the value and character of sliding speed variation, on the angular and linear acceleration of the teeth contact point in the boundaries of a precessional cycle, are important for the prognosis of kinematical planetary precessional transmissions behaviour at the design phase.

This paper describes the undertaken experimental research on the kinematical precessional transmissions with the purpose to determine the basic functional characteristics such as: mechanical efficiency, level of noise and vibrations, bearing capacity. The calculation methodology of kinematical planetary precessional reducers was elaborated and verified.

The utilisation of the measuring and data processing devices based on the LabView operational system and of the modern experimental stands allowed the verification of result correctness obtained theoretically and by numeric simulation, which fact ensures rapid optimisation of kinematical planetary precessional transmissions.

On the basis of theoretical and experimental research, complex modelling carried out by author a series of driving mechanisms were designed based on kinematical planetary precessional transmissions which can be utilised in various fields.

For future research it is proposed to analyse more thoroughly the gearing of kinematical planetary precessional transmissions with the purpose of its optimisation under the aspect of reducing power losses in the gearing and constructive and technological simplicity.